General Chemistry 10th Edition by Darrell Ebbing – Test Bank A+

Description

1. The energy associated with the separation of two electrical charges is called _____.

A)	heat
B)	internal energy
C)	temperature
D)	kinetic energy
E)	potential energy

ANS: E PTS: 1 DIF: easy REF: 6.1

OBJ: Define energy, kinetic energy, potential energy, and internal energy.

TOP: thermochemistry | heats of reaction

1. The energy associated with the motion of a speeding bullet is called _____.

A)	heat
B)	internal energy
C)	temperature
D)	kinetic energy
E)	potential energy

ANS: D PTS: 1 DIF: easy REF: 6.1

OBJ: Define energy, kinetic energy, potential energy, and internal energy.

TOP: thermochemistry | heats of reaction

1. The air whipped up by a tornado possesses what type(s) of energy?

A)	potential energy only
B)	internal energy only
C)	kinetic energy only
D)	kinetic energy, potential energy, and internal energy
E)	kinetic energy and potential energy only

ANS: D PTS: 1 DIF: easy REF: 6.1

OBJ: Define energy, kinetic energy, potential energy, and internal energy.

TOP: thermochemistry | heats of reaction

1. The internal energy of a substance is defined as

A)	the potential energy of all particles which make up the substance.
B)	the kinetic energy of all particles which make up the substance.
C)	the sum of the potential and kinetic energy of all particles which make up the substance.
D)	the thermal energy of all particles which make up the substance.
E)	the chemical energy of all particles which make up the substance.

ANS: C PTS: 1 DIF: easy REF: 6.1

OBJ: Define energy, kinetic energy, potential energy, and internal energy.

TOP: thermochemistry | heats of reaction

1. What is the kinetic energy of a 2000-lb car traveling at 48 miles per hour? (1 lb = 0.4536 kg, 1 mi = 1.609 km)

A)	2.1 ´ 10–7 J
B)	1.0 ´ 106 J
C)	3.5 ´ 1019 J
D)	2.1 ´ 105 J
E)	3.1 ´ 10–8 J

ANS: D PTS: 1 DIF: easy REF: 6.1

OBJ: Calculate the kinetic energy of a moving object. (Example 6.1)

TOP: thermochemistry | heats of reaction KEY: energy | kinetic energy

MSC: general chemistry

1. Calculate DU of a gas for a process in which the gas absorbs 9 J of heat and does 25 J of work by expanding.

A)	16 J
B)	34 J
C)	–34 J
D)	0, because DU is a state function
E)	–16 J

ANS: E PTS: 1 DIF: easy REF: 6.2

OBJ: State the law of conservation of energy.

TOP: thermochemistry | heats of reaction KEY: energy | law of conservation of energy

MSC: general chemistry

1. Which of the following is an endothermic process?

A)	work is done by the system on the surroundings
B)	heat energy flows from the system to the surroundings
C)	work is done on the system by the surroundings
D)	heat energy is evolved by the system
E)	none of the above

ANS: C PTS: 1 DIF: moderate REF: 6.3

OBJ: Distinguish between an exothermic process and an endothermic process.

TOP: thermochemistry | heats of reaction

1. Which of the following does not result in a change in the internal energy of the system?

A)	work is done on the system
B)	work is done on the surroundings
C)	heat flows into the system
D)	heat flows to the surroundings
E)	none of the above

ANS: E PTS: 1 DIF: easy REF: 6.2

OBJ: Define work and heat. | Define the change in internal energy of a system.

TOP: thermochemistry | heats of reaction

1. Which of the following statements about heat is false?

A)	If heat flows into a system, the extra energy of the system appears in the form of internal energy.
B)	A hot object possesses more heat than a cold object.
C)	If the system and surroundings are in thermal equilibrium, there is no heat flow between them.
D)	A process in which heat flows out of a system is said to be exothermic.
E)	Heat is a form of energy flow.

ANS: B PTS: 1 DIF: easy REF: 6.2

OBJ: Define heat and heat of reaction. TOP: thermochemistry | heats of reaction

KEY: heat MSC: general chemistry

1. If q = –91 kJ for a certain process, that process

A)	requires a catalyst.
B)	is exothermic.
C)	occurs rapidly.
D)	is endothermic.
E)	cannot occur.

ANS: B PTS: 1 DIF: easy REF: 6.3

OBJ: Distinguish between an exothermic process and an endothermic process.

TOP: thermochemistry | heats of reaction KEY: heat | heat of reaction

MSC: general chemistry

1. If q = 28 kJ and w = 85 kJ for a certain process, that process

A)	requires a catalyst.
B)	is endothermic.
C)	occurs slowly.
D)	is exothermic.
E)	cannot occur.

ANS: B PTS: 1 DIF: easy to moderate

REF: 6.3

OBJ: Distinguish between an exothermic process and an endothermic process.

TOP: thermochemistry | heats of reaction

1. What is the change in internal energy of the system (DU) if 10 kJ of heat energy is absorbed by the system and 70 kJ of work is done by the system for a certain process?

A)	–60 kJ
B)	80 kJ
C)	10 kJ
D)	60 kJ
E)	–80 kJ

ANS: A PTS: 1 DIF: moderate REF: 6.2

OBJ: Express the first law of thermodynamics mathematically.

TOP: thermochemistry | heats of reaction

1. At constant pressure, the sign of q for the process CO₂(s) ® CO₂(g) is expected to be

A)	positive, and the process is exothermic.
B)	negative, and the process is exothermic.
C)	impossible to predict.
D)	positive, and the process is endothermic.
E)	negative, and the process is endothermic.

ANS: D PTS: 1 DIF: easy REF: 6.3

OBJ: Distinguish between an exothermic process and an endothermic process.

TOP: thermochemistry | heats of reaction KEY: heat | heat of reaction

MSC: general chemistry

1. At constant pressure, the sign of q for the process H₂O(l) ® H₂O(s) is expected to be

A)	positive, and the process is exothermic.
B)	negative, and the process is endothermic.
C)	impossible to predict.
D)	negative, and the process is exothermic.
E)	positive, and the process is endothermic.

ANS: D PTS: 1 DIF: easy REF: 6.2

OBJ: Distinguish between an exothermic process and an endothermic process.

TOP: thermochemistry | heats of reaction KEY: heat | heat of reaction

MSC: general chemistry

1. Which of the following statements is not true for an exothermic reaction?

A)	The products have a higher heat content than the reactants.
B)	The temperature of the reaction system increases.
C)	The temperature of the surroundings increases.
D)	Heat passes from the reaction system to the surroundings.
E)	The enthalpy change for the reaction is negative.

ANS: A PTS: 1 DIF: easy REF: 6.2

OBJ: Distinguish between an exothermic process and an endothermic process.

TOP: thermochemistry | heats of reaction KEY: enthalpy | enthalpy change

MSC: general chemistry

1. H₂ and F₂ react according to the following equation, forming HF.

H₂(g) + F₂(g) ® 2HF(g); DH° = –271 kJ

If H₂(g) and F₂(g) were mixed in a thermally insulated vessel, the reaction that occurred would be

A)	endothermic, and the temperature of the reaction system would fall.
B)	We could not tell unless the original and final temperatures were given.
C)	exothermic, and the temperature of the reaction system would fall.
D)	exothermic, and the temperature of the reaction system would rise.
E)	endothermic, and the temperature of the reaction system would rise.

ANS: D PTS: 1 DIF: easy REF: 6.3

OBJ: Distinguish between an exothermic process and an endothermic process.

TOP: thermochemistry | heats of reaction KEY: enthalpy | enthalpy of reaction

MSC: general chemistry

1. Which of the following statements is incorrect?

A)	Internal energy is a state function.
B)	The value of q is positive when heat flows into a system from the surroundings.
C)	The value of q is positive in an endothermic process.
D)	Heat flows from a system into the surroundings in an endothermic process.
E)	Enthalpy is a state function.

ANS: D PTS: 1 DIF: easy REF: 6.2

OBJ: Distinguish between an exothermic process and an endothermic process.

TOP: thermochemistry | heats of reaction KEY: heat MSC: general chemistry

1. Which of the following statements about enthalpy is false?

A)	Enthalpy is a state function.
B)	At constant pressure, the enthalpy change is equal to the heat absorbed or released.
C)	Enthalpy is an extensive property.
D)	The change in enthalpy of a process cannot be negative.
E)	The SI unit of enthalpy is J.

ANS: D PTS: 1 DIF: easy REF: 6.3

OBJ: Define enthalpy and enthalpy of reaction.

TOP: thermochemistry | heats of reaction KEY: enthalpy MSC: general chemistry

1. The phrase “the heat absorbed or released by a system undergoing a physical or chemical change at constant pressure” is

A)	the change in enthalpy of the system.
B)	the change in internal energy of the system.
C)	the definition of a state function.
D)	the temperature change of the system.
E)	a statement of Hess’s law.

ANS: A PTS: 1 DIF: easy REF: 6.3

OBJ: Explain how the terms enthalpy of reaction and heat of reaction are related.

TOP: thermochemistry | heats of reaction KEY: enthalpy | enthalpy change

MSC: general chemistry

1. Which of the following statements is true concerning the decomposition of liquid water to form hydrogen gas and oxygen gas?

2H₂O(l) ® 2H₂(g) + O₂(g)

A)	DH is greater than DU because the pressure is constant.
B)	DH is less than DU because of the pressure–volume work done by the gaseous products.
C)	DH is less than DU because the atmosphere does pressure–volume work on the gaseous products.
D)	DH equals DU because both are state functions.
E)	DH is greater than DU because of the pressure–volume work done by the gaseous products.

ANS: E PTS: 1 DIF: moderate REF: 6.3

OBJ: Explain how enthalpy and internal energy are related.

TOP: thermochemistry | heats of reaction KEY: enthalpy | enthalpy and internal energy

MSC: general chemistry

1. Under conditions of constant pressure, for which of the following reactions is the magnitude of pressure-volume work going to be greatest?

A)	BaO(s) + SO3(g) ® BaSO4(s)
B)	2NO(g) + O2(g) ® 2NO2(g)
C)	2H2O2(l) ® 2H2O(l) + O2(g)
D)	2KClO3(s) ® 2KCl(s) + 3O2(g)
E)	H2(g) + Cl2(g) ® 2HCl(g)

ANS: D PTS: 1 DIF: moderate REF: 6.3

OBJ: Describe pressure-volume work verbally and mathematically.

TOP: thermochemistry | heats of reaction

1. Under conditions of constant pressure, for which of the following reactions is the magnitude of pressure-volume work going to be smallest?

A)	BaO(s) + SO3(g) ® BaSO4(s)
B)	2NO(g) + O2(g) ® 2NO2(g)
C)	2H2O2(l) ® 2H2O(l) + O2(g)
D)	2KClO3(s) ® 2KCl(s) + 3O2(g)
E)	H2(g) + Cl2(g) ® 2HCl(g)

ANS: E PTS: 1 DIF: moderate REF: 6.3

OBJ: Describe pressure-volume work verbally and mathematically.

TOP: thermochemistry | heats of reaction

1. Which of the following sentences accurately describes the thermochemical equation given below?

2Ag(s) + F₂(g) ® 2AgF(s); DH = –409.2 kJ

A)	If 2 mol of silver metal react with 1 mol of fluorine gas at constant volume, 2 mol of solid sodium fluoride is produced and 409.2 kJ of heat is consumed.
B)	If 2 atoms of silver metal react with 1 molecule of fluorine gas at constant pressure, 2 formula units of solid sodium fluoride are produced and 409.2 kJ of heat is released.
C)	If 2 atoms of silver metal react with 1 molecule of fluorine gas at constant pressure, 2 formula units of solid sodium fluoride are produced and 409.2 kJ of heat is consumed.
D)	If 2 mol of silver metal react with 1 mol of fluorine gas at constant pressure, 2 mol of solid sodium fluoride is produced and 409.2 kJ of heat is consumed.
E)	If 2 mol of silver metal react with 1 mol of fluorine gas at constant pressure, 2 mol of solid sodium fluoride is produced and 409.2 kJ of heat is released.

ANS: E PTS: 1 DIF: easy REF: 6.4

OBJ: Write a thermochemical equation given pertinent information. (Example 6.2)

TOP: thermochemistry | heats of reaction KEY: thermochemical equation

MSC: general chemistry

1. Which of the following statements is incorrect concerning the thermochemical equation below?

2SO₃(g) ® 2SO₂(g) + O₂(g); DH° = 198 kJ

A)	The enthalpy of the reactants exceeds that of the products.
B)	The reaction is endothermic.
C)	For the reaction 2SO2(g) + O2(g) ® 2SO3(g), DH° = –198 kJ.
D)	The external pressure is 1 atm.
E)	For every mole of SO3(g) consumed, 99 kJ of heat at constant pressure is consumed as well.

ANS: A PTS: 1 DIF: easy REF: 6.4

OBJ: Write a thermochemical equation given pertinent information. (Example 6.2)

TOP: thermochemistry | heats of reaction KEY: thermochemical equation

MSC: general chemistry

1. In a certain experiment, 0.1000 mol of hydrogen gas reacted with 0.1000 mol of solid iodine at a constant 1 atm pressure, producing 0.2000 mol of solid hydrogen iodide and absorbing 5.272 kJ of heat in the process. Which of the following thermochemical equations correctly describes this experiment?

A)	H2(g) + I2(s) ® 2HI(s); DH° = –52.72 kJ
B)	H2(g) + I2(s) ® 2HI(s); DH° = 5.272 kJ
C)	H2(g) + I2(s) ® 2HI(s); DH° = –5.272 kJ
D)	H2(g) + I2(s) ® 2HI(s); DH° = 10.54 kJ
E)	H2(g) + I2(s) ® 2HI(s); DH° = 52.72 kJ

ANS: E PTS: 1 DIF: difficult REF: 6.4

OBJ: Write a thermochemical equation given pertinent information. (Example 6.2)

TOP: thermochemistry | heats of reaction KEY: thermochemical equation

MSC: general chemistry

1. Given:

4AlCl₃(s) + 3O₂(g) ® 2Al₂O₃(s) + 6Cl₂(g); DH = –529.0 kJ

determine DH for the following thermochemical equation.

Cl₂(g) + Al₂O₃(s) ® AlCl₃(s) + O₂(g)

A)	+264.5 kJ
B)	+529.0 kJ
C)	+88.2 kJ
D)	+176.3 kJ
E)	–176.3 kJ

ANS: C PTS: 1 DIF: easy REF: 6.4

OBJ: Manipulate a thermochemical equation using these rules. (Example 6.3)

TOP: thermochemistry | heats of reaction KEY: thermochemical equation

MSC: general chemistry

1. Given the thermochemical equation

2Al(s) + O₂(g) ® Al₂O₃(s); DH = –1676 kJ

find DH for the following reaction.

2Al₂O₃(s) ® 4Al(s) + 3O₂(g)

A)	838 kJ
B)	1676 kJ
C)	–1676 kJ
D)	3352 kJ
E)	–838 kJ

ANS: D PTS: 1 DIF: easy REF: 6.4

OBJ: Manipulate a thermochemical equation using these rules. (Example 6.3)

TOP: thermochemistry | heats of reaction

KEY: thermochemical equation | enthalpy of reaction MSC: general chemistry

1. Given:

what is DH for the following thermochemical equation?

A)	986.9 kJ
B)	-986.9 kJ
C)	–139 MJ
D)	–2320 kJ
E)	–38.7 kJ

ANS: A PTS: 1 DIF: easy REF: 6.4

OBJ: Manipulate a thermochemical equation using these rules. (Example 6.3)

TOP: thermochemistry | heats of reaction

1. Which of the following statements is false concerning the reaction of hydrogen gas and oxygen gas given below?

H₂(g) + O₂(g) ® H₂O(l); DH = –285.8 kJ

A)	Per mole of O2, the change in enthalpy is –571.6 kJ.
B)	The value –571.6 kJ pertains to 1 mol of liquid water.
C)	If the equation is reversed, DH becomes +285.8 kJ.
D)	If the equation is multiplied by 2, DH becomes –571.6 kJ.
E)	For the reaction H2(g) + O2(g) ® H2O(g), DH is not equal to –285.8 kJ.

ANS: B PTS: 1 DIF: moderate REF: 6.4

OBJ: Manipulate a thermochemical equation using these rules. (Example 6.3)

TOP: thermochemistry | heats of reaction KEY: thermochemical equation

MSC: general chemistry

1. What is the change in enthalpy when 4.00 mol of sulfur trioxide decomposes to sulfur dioxide and oxygen gas?

2SO₂(g) + O₂(g) ® 2SO₃(g); DH° = 198 kJ

A)	396 kJ
B)	–198 kJ
C)	–396 kJ
D)	198 kJ
E)	792 kJ

ANS: C PTS: 1 DIF: easy REF: 6.5

OBJ: Calculate the heat absorbed or evolved from a reaction given its enthalpy of reaction and the mass of a reactant or product. (Example 6.4)

TOP: thermochemistry | heats of reaction

KEY: thermochemical equation | stoichiometry and heats of reaction

MSC: general chemistry

1. What is the change in enthalpy at 25°C and 1 atm for the production of 9.00 mol SnO(s)?

Sn(s) + SnO₂(s) ® 2SnO(s); DH° = 16.2 kJ

A)	–72.9 kJ
B)	–16.2 kJ
C)	16.2 kJ
D)	1.80 kJ
E)	72.9 kJ

ANS: E PTS: 1 DIF: easy REF: 6.5

OBJ: Calculate the heat absorbed or evolved from a reaction given its enthalpy of reaction and the mass of a reactant or product. (Example 6.4)

TOP: thermochemistry | heats of reaction

KEY: thermochemical equation | stoichiometry and heats of reaction

MSC: general chemistry

1. What is the change in enthalpy at 25°C and 1 atm for the reaction of 5.00 mol of elemental iron with excess oxygen gas?

4Fe(s) + 3O₂(g) ® 2Fe₂O₃(s); DH° = –1651 kJ

A)	-1651 kJ
B)	2752 kJ
C)	2064 kJ
D)	–2064 kJ
E)	-412.8 kJ

ANS: D PTS: 1 DIF: easy REF: 6.5

OBJ: Calculate the heat absorbed or evolved from a reaction given its enthalpy of reaction and the mass of a reactant or product. (Example 6.4)

TOP: thermochemistry | heats of reaction

1. What is the quantity of heat evolved at constant pressure when 60.3 g H₂O(l) is formed from the combustion of H₂(g) and O₂(g)?

H₂(g) + O₂(g) ® H₂O(l); DH° = –285.8 kJ

A)	1.17 ´ 10–2 kJ
B)	285.8 kJ
C)	1.72 ´ 104 kJ
D)	85.4 kJ
E)	9.57 ´ 102 kJ

ANS: E PTS: 1 DIF: easy REF: 6.5

OBJ: Calculate the heat absorbed or evolved from a reaction given its enthalpy of reaction and the mass of a reactant or product. (Example 6.4)

TOP: thermochemistry | heats of reaction

KEY: thermochemical equation | stoichiometry and heats of reaction

MSC: general chemistry

1. What quantity, in moles, of hydrogen is consumed when 676.8 kJ of energy is evolved from the combustion of a mixture of H₂(g) and O₂(g)?

H₂(g) + O₂(g) ® H₂O(l); DH° = –285.8 kJ

A)	2.368 mol
B)	1.184 mol
C)	0.4223 mol
D)	3.368 mol
E)	1.368 mol

ANS: A PTS: 1 DIF: easy REF: 6.5

OBJ: Calculate the heat absorbed or evolved from a reaction given its enthalpy of reaction and the mass of a reactant or product. (Example 6.4)

TOP: thermochemistry | heats of reaction

1. What mass of hydrogen is consumed when 587.9 kJ of energy is evolved from the combustion of a mixture of H₂(g) and O₂(g)?

H₂(g) + O₂(g) ® H₂O(l); DH° = –285.8 kJ

A)	4.147 g
B)	2.073 g
C)	0.2412 g
D)	6.162 g
E)	2.131 g

ANS: A PTS: 1 DIF: easy REF: 6.5

OBJ: Calculate the heat absorbed or evolved from a reaction given its enthalpy of reaction and the mass of a reactant or product. (Example 6.4)

TOP: thermochemistry | heats of reaction

1. According to the following thermochemical equation, if 951.1 g of NO₂ is produced, how much heat is released at constant pressure?

2NO(g) + O₂(g) ® 2NO₂(g); DH° = –114.4 kJ

A)	114.4 kJ
B)	1.183 ´ 103 kJ
C)	2.365 ´ 103 kJ
D)	5.534 kJ
E)	1.088 ´ 105 kJ

ANS: B PTS: 1 DIF: easy REF: 6.5

OBJ: Calculate the heat absorbed or evolved from a reaction given its enthalpy of reaction and the mass of a reactant or product. (Example 6.4)

TOP: thermochemistry | heats of reaction

KEY: thermochemical equation | stoichiometry and heats of reaction

MSC: general chemistry

1. Consider the following thermochemical equation:

N₂(g) + 2O₂(g) ® 2NO₂(g); DH° = 66.2 kJ

From this equation, we may conclude that 66.2 kJ is the quantity of heat that is

A)	gained from the surroundings when 1 mol of NO2 is formed at constant pressure.
B)	lost to the surroundings when 1 mol of NO2 is formed at constant pressure.
C)	gained from the surroundings when 2 mol of NO2 is formed at constant pressure.
D)	lost to the surroundings when 2 mol of NO2 is formed at constant pressure.
E)	lost to the surroundings when 1 mol of O2 is consumed at constant pressure.

ANS: C PTS: 1 DIF: easy REF: 6.5

OBJ: Calculate the heat absorbed or evolved from a reaction given its enthalpy of reaction and the mass of a reactant or product. (Example 6.4)

TOP: thermochemistry | heats of reaction

KEY: thermochemical equation | stoichiometry and heats of reaction

MSC: general chemistry

1. How much heat is liberated at constant pressure if 0.834 g of calcium carbonate reacts with 48.9 mL of 0.668 M hydrochloric acid?

CaCO₃(s) + 2HCl(aq) ® CaCl₂(aq) + H₂O(l) + CO₂(g); DH° = –15.2 kJ

A)	–0.127 kJ
B)	–0.375 kJ
C)	–12.7 kJ
D)	–0.248 kJ
E)	–10.2 kJ

ANS: A PTS: 1 DIF: moderate REF: 6.5

OBJ: Calculate the heat absorbed or evolved from a reaction given its enthalpy of reaction and the mass of a reactant or product. (Example 6.4)

TOP: thermochemistry | heats of reaction

KEY: thermochemical equation | stoichiometry and heats of reaction

MSC: general chemistry

1. When 34.1 g of lead reacts with 6.81 L of oxygen gas, measured at 1.00 atm and 25.0°C, 36.1 kJ of heat is released at constant pressure. What is DH° for this reaction? (R = 0.0821 L • atm/(K • mol))

2Pb(s) + O₂(g) ® 2PbO(s)

A)	–4.39 ´ 102 kJ
B)	–5.94 ´ 101 kJ
C)	–3.61 ´ 101 kJ
D)	–2.19 ´ 102 kJ
E)	–1.30 ´ 102 kJ

ANS: A PTS: 1 DIF: moderate REF: 6.5

OBJ: Calculate the heat absorbed or evolved from a reaction given its enthalpy of reaction and the mass of a reactant or product. (Example 6.4)

TOP: thermochemistry | heats of reaction

KEY: thermochemical equation | stoichiometry and heats of reaction

MSC: general chemistry

1. How much heat is evolved upon the complete oxidation of 9.118 g of aluminum at 25°C and 1 atm pressure? ( for Al₂O₃ is –1676 kJ/mol.)

4Al(s) + 3O₂(g) ® 2Al₂O₃(s)

A)	1.528 ´ 104 kJ
B)	566.4 kJ
C)	1133 kJ
D)	283.2 kJ
E)	141.6 kJ

ANS: D PTS: 1 DIF: moderate REF: 6.5

OBJ: Calculate the heat absorbed or evolved from a reaction given its enthalpy of reaction and the mass of a reactant or product. (Example 6.4)

TOP: thermochemistry | heats of reaction

KEY: thermochemical equation | stoichiometry and heats of reaction

MSC: general chemistry

1. The reaction of iron with hydrochloric acid is represented by the following thermochemical equation.

Fe(s) + 2HCl(aq) ® FeCl₂(aq) + H₂(g); DH° = –87.9 kJ

How much heat is liberated at constant pressure if 0.358 g of iron reacts with 34.1 mL of 0.588 M HCl?

A)	4.09 kJ
B)	31.5 kJ
C)	0.563 kJ
D)	0.881 kJ
E)	87.9 kJ

ANS: C PTS: 1 DIF: moderate REF: 6.5

OBJ: Calculate the heat absorbed or evolved from a reaction given its enthalpy of reaction and the mass of a reactant or product. (Example 6.4)

TOP: thermochemistry | heats of reaction

KEY: thermochemical equation | stoichiometry and heats of reaction

MSC: general chemistry

1. At constant pressure and 25°C, what is DH° for the following reaction

2C₂H₆(g) + 7O₂(g) ® 4CO₂(g) + H₂O(l)

if the complete consumption of 11.3 g of C₂H₆ liberates –586.3 kJ of heat energy?

A)	–3120 kJ
B)	–1560 kJ
C)	–441 kJ
D)	–222 kJ
E)	–786 kJ

ANS: A PTS: 1 DIF: moderate REF: 6.5

OBJ: Calculate the heat absorbed or evolved from a reaction given its enthalpy of reaction and the mass of a reactant or product. (Example 6.4)

1. The reaction of iron with hydrochloric acid is represented by the following thermochemical equation.

Fe(s) + 2HCl(aq) ® FeCl₂(aq) + H₂(g); DH° = –87.9 kJ

If, in a particular experiment, 7.36 kJ of heat was released at constant pressure, what volume of H₂(g), measured at STP, was produced? (R = 0.0821 L • atm/(K • mol))

A)	2.92 ´ 102 L
B)	2.05 L
C)	22.4 L
D)	2.68 ´ 102 L
E)	1.88 L

ANS: E PTS: 1 DIF: moderate REF: 6.5

OBJ: Calculate the heat absorbed or evolved from a reaction given its enthalpy of reaction and the mass of a reactant or product. (Example 6.4)

TOP: thermochemistry | heats of reaction

KEY: thermochemical equation | stoichiometry and heats of reaction

MSC: general chemistry

1. The reaction of iron with hydrochloric acid is represented by the following thermochemical equation.

Fe(s) + 2HCl(aq) ® FeCl₂(aq) + H₂(g); DH° = –87.9 kJ

In which of the following experiments would the temperature rise the most?

A)	2.2 g of Fe added to 1.0 L of 0.03 M HCl
B)	1.1 g of Fe added to 1.0 L of 0.02 M HCl
C)	4.5 g of Fe added to 1.0 L of 0.03 M HCl
D)	1.1 g of Fe added to 1.0 L of 0.04 M HCl
E)	0.56 g of Fe added to 1.0 L of 0.02 M HCl

ANS: D PTS: 1 DIF: moderate REF: 6.5

OBJ: Calculate the heat absorbed or evolved from a reaction given its enthalpy of reaction and the mass of a reactant or product. (Example 6.4)

TOP: thermochemistry | heats of reaction

KEY: thermochemical equation | stoichiometry and heats of reaction

MSC: general chemistry

1. How much heat is released at constant pressure if 16.9 mL of 0.694 M silver nitrate is mixed with 79.7 mL of 0.372 M potassium chloride?

AgNO₃(aq) + KCl(aq) ® AgCl(s) + KNO₃(aq); DH° = –65.5 kJ

A)	–0.768 kJ
B)	–24.4 kJ
C)	–1.94 kJ
D)	–45.5 kJ
E)	–2.71 kJ

ANS: A PTS: 1 DIF: difficult REF: 6.5

OBJ: Calculate the heat absorbed or evolved from a reaction given its enthalpy of reaction and the mass of a reactant or product. (Example 6.4)

TOP: thermochemistry | heats of reaction

KEY: thermochemical equation | stoichiometry and heats of reaction

MSC: general chemistry

1. How much heat is liberated at constant pressure when 58.5 g of calcium oxide reacts with 83.9 L of carbon dioxide gas, measured at 1.00 atm pressure and 25.0°C? (R = 0.0821 L • atm/(K • mol))

CaO(s) + CO₂(g) ® CaCO₃(s); DH° = –178.3 kJ

A)	–6.11 ´ 102 kJ
B)	–1.04 ´ 104 kJ
C)	–7.97 ´ 102 kJ
D)	–1.86 ´ 102 kJ
E)	–1.50 ´ 104 kJ

ANS: D PTS: 1 DIF: difficult REF: 6.5

OBJ: Calculate the heat absorbed or evolved from a reaction given its enthalpy of reaction and the mass of a reactant or product. (Example 6.4)

TOP: thermochemistry | heats of reaction

KEY: thermochemical equation | stoichiometry and heats of reaction

MSC: general chemistry

1. When 32.4 mL of liquid benzene (C₆H₆, d = 0.879 g/mL) reacts with 81.6 L of oxygen gas, measured at 1.00 atm pressure and 25°C, 1.19 ´ 10³ kJ of heat is released at constant pressure. What is DH° for the following reaction? (R = 0.0821 L • atm/(K • mol))

2C₆H₆(l) + 15O₂(g) ® 12CO₂(g) + 6H₂O(l)

A)	–2.35 ´ 101 kJ
B)	–3.22 ´ 102 kJ
C)	–5.36 ´ 103 kJ
D)	–3.27 ´ 103 kJ
E)	–6.53 ´ 103 kJ

ANS: E PTS: 1 DIF: difficult REF: 6.5

OBJ: Calculate the heat absorbed or evolved from a reaction given its enthalpy of reaction and the mass of a reactant or product. (Example 6.4)

TOP: thermochemistry | heats of reaction

KEY: thermochemical equation | stoichiometry and heats of reaction

MSC: general chemistry

1. When 49.4 mL of 0.721 M lead(II) nitrate reacts with 99.6 mL of 0.807 M sodium chloride, 0.830 kJ of heat is released at constant pressure. What is DH° for this reaction?

Pb(NO₃)₂(aq) + 2NaCl(aq) ® PbCl₂(s) + 2NaNO₃(aq)

A)	–23.3 kJ
B)	–10.3 kJ
C)	–4.23 kJ
D)	–7.15 kJ
E)	–20.6 kJ

ANS: A PTS: 1 DIF: difficult REF: 6.5

OBJ: Calculate the heat absorbed or evolved from a reaction given its enthalpy of reaction and the mass of a reactant or product. (Example 6.4)

TOP: thermochemistry | heats of reaction

KEY: thermochemical equation | stoichiometry and heats of reaction

MSC: general chemistry

1. A 9.020-g sample of an unknown metal M is burned in the presence of excess oxygen, producing the oxide M₂O₃(s) and liberating 191.5 kJ of heat at constant pressure. What is the identity of the metal?

4M(s) + 3O₂(g) ® 2M₂O₃(s)

Substance	DH°f (kJ/mol)
Yb2O3(s)	–1814.6
Tb2O3(s)	–1865.2
Sm2O3(s)	–1823.0
Sc2O3(s)	–1908.8
Y2O3(s)	–1905.3

A)	Sm
B)	Sc
C)	Yb
D)	Y
E)	Tb

ANS: B PTS: 1 DIF: difficult REF: 6.5

OBJ: Calculate the heat absorbed or evolved from a reaction given its enthalpy of reaction and the mass of a reactant or product. (Example 6.4)

TOP: thermochemistry | heats of reaction

KEY: thermochemical equation | stoichiometry and heats of reaction

MSC: general chemistry

1. A 5.09-g sample of solid silver reacted in excess chlorine gas to give a 6.76-g sample of pure solid AgCl. The heat given off in this reaction was 6.00 kJ at constant pressure. Given this information, what is the enthalpy of formation of AgCl(s)?

A)	–127 kJ/mol
B)	–63.6 kJ/mol
C)	127 kJ/mol
D)	–6.00 kJ/mol
E)	6.00 kJ/mol

ANS: A PTS: 1 DIF: difficult REF: 6.5

OBJ: Calculate the heat absorbed or evolved from a reaction given its enthalpy of reaction and the mass of a reactant or product. (Example 6.4)

TOP: thermochemistry | heats of reaction

KEY: thermochemical equation | stoichiometry and heats of reaction

MSC: general chemistry

1. A 2.19-g sample of solid calcium reacted in excess fluorine gas to give a 4.27-g sample of pure solid CaF₂. The heat given off in this reaction was 67.0 kJ at constant pressure. Given this information, what is the enthalpy of formation of CaF₂(s)?

A)	67.0 kJ/mol
B)	–67.0 kJ/mol
C)	–1.23 ´ 103 kJ/mol
D)	–613 kJ/mol
E)	1.23 ´ 103 kJ/mol

ANS: C PTS: 1 DIF: difficult REF: 6.5

OBJ: Calculate the heat absorbed or evolved from a reaction given its enthalpy of reaction and the mass of a reactant or product. (Example 6.4)

TOP: thermochemistry | heats of reaction

KEY: thermochemical equation | stoichiometry and heats of reaction

MSC: general chemistry

1. The quantity of heat required to raise the temperature of a sample of a substance by 1°C is the sample’s

A)	work.
B)	calorimetry.
C)	heat capacity.
D)	specific heat.
E)	enthalpy.

ANS: C PTS: 1 DIF: easy REF: 6.6

OBJ: Define heat capacity and specific heat.

TOP: thermochemistry | heats of reaction KEY: calorimetry | heat capacity

MSC: general chemistry

1. The units for heat capacity are

A)	J/g.
B)	(J · g).
C)	J/°C.
D)	(J · °C).
E)	J/(g · °C).

ANS: C PTS: 1 DIF: easy REF: 6.6

OBJ: Define heat capacity and specific heat.

TOP: thermochemistry | heats of reaction KEY: calorimetry | heat capacity

MSC: general chemistry

1. The units for specific heat are

A)	J/(g · °C).
B)	(J · °C).
C)	J/g.
D)	J/°C.
E)	(J · g).

ANS: A PTS: 1 DIF: easy REF: 6.6

OBJ: Define heat capacity and specific heat.

TOP: thermochemistry | heats of reaction KEY: calorimetry | heat capacity

MSC: general chemistry

1. The specific heat capacity of copper is 0.384 J/g×°C. What is the molar specific heat capacity of this substance? The molar mass of copper is 63.54 g/mol.

A)	24.4 J/mol×°C
B)	0.00604 J/mol×°C
C)	165 J/mol×°C
D)	0.384 J/mol×°C
E)	2.60 J/mol×°C

ANS: A PTS: 1 DIF: easy REF: 6.6

OBJ: Calculate molar specific heat capacity.

TOP: thermochemistry | heats of reaction

1. The heat required to raise the temperature of 52.00 g of chromium by 1°C is called its

A)	heat of vaporization.
B)	specific heat.
C)	heat of fusion.
D)	entropy.
E)	molar heat capacity.

ANS: E PTS: 1 DIF: easy REF: 6.6

OBJ: Define heat capacity and specific heat.

TOP: thermochemistry | heats of reaction KEY: calorimetry | heat capacity

MSC: general chemistry

1. The molar heat capacity of gaseous heptane at 25.0°C is 165.2 J/(mol · °C). What is its specific heat?

A)	0.6065 J/(g · °C)
B)	1.649 J/(g · °C)
C)	6.041 ´ 10–5 J/(g · °C)
D)	165.2 J/(g · °C)
E)	1.655 ´ 104 J/(g · °C)

ANS: B PTS: 1 DIF: easy REF: 6.6

OBJ: Define heat capacity and specific heat.

TOP: thermochemistry | heats of reaction KEY: calorimetry | heat capacity

MSC: general chemistry

1. A 100 g sample of each of the following metals is heated from 35°C to 45°C. Which metal absorbs the lowest amount of heat energy?

Metal	Specific Heat
copper	0.385 J/(g · °C)
magnesium	1.02 J/(g · °C)
mercury	0.138 J/(g · °C)
silver	0.237 J/(g · °C)
lead	0.129 J/(g · °C)

A)	lead
B)	magnesium
C)	silver
D)	mercury
E)	copper

ANS: A PTS: 1 DIF: easy REF: 6.6

OBJ: Relate the heat absorbed or evolved to the specific heat, mass, and temperature change. TOP: thermochemistry | heats of reaction

1. Two metals of equal mass with different heat capacities are subjected to the same amount of heat. Which undergoes the smaller change in temperature?

A)	The metal with the higher heat capacity undergoes the smaller change in temperature.
B)	Both undergo the same change in temperature.
C)	You need to know the initial temperatures of the metals.
D)	You need to know which metals you have.
E)	The metal with the lower heat capacity undergoes the smaller change in temperature.

ANS: A PTS: 1 DIF: moderate REF: 6.6

OBJ: Relate the heat absorbed or evolved to the specific heat, mass, and temperature change. TOP: thermochemistry | heats of reaction

KEY: calorimetry | specific heat MSC: general chemistry

1. It is relatively easy to change the temperature of a substance that

A)	is very massive.
B)	is an insulator.
C)	has a high specific heat capacity.
D)	has a low specific heat capacity.
E)	is brittle.

ANS: D PTS: 1 DIF: easy REF: 6.6

OBJ: Relate the heat absorbed or evolved to the specific heat, mass, and temperature change. TOP: thermochemistry | heats of reaction

KEY: calorimetry | specific heat MSC: general chemistry

1. How much heat is gained by copper when 51.8 g of copper is warmed from 15.5°C to 76.4°C? The specific heat of copper is 0.385 J/(g · °C).

A)	3.09 ´ 102 J
B)	29.41 J
C)	23.45 J
D)	1.21 ´ 103 J
E)	1.52 ´ 103 J

ANS: D PTS: 1 DIF: moderate REF: 6.6

OBJ: Calculate using this relation between heat and specific heat. (Example 6. 5)

TOP: thermochemistry | heats of reaction KEY: calorimetry | measuring heats of reaction

MSC: general chemistry

1. Which of the following processes will result in the lowest final temperature of the metal–water mixture at equilibrium?

A)	the addition of 100 g of silver (s = 0.237 J/(g · °C)) at 95°C to 100 mL of water at 25°C in an insulated container
B)	the addition of 100 g of cobalt (s = 0.418 J/(g · °C)) at 95°C to 100 mL of water at 25°C in an insulated container
C)	the addition of 100 g of chromium (s = 0.447 J/(g · °C)) at 95°C to 100 mL of water at 25°C in an insulated container
D)	the addition of 100 g of copper (s = 0.385 J/(g · °C)) at 95°C to 100 mL of water at 25°C in an insulated container
E)	the addition of 100 g of gold (s = 0.129 J/(g · °C)) at 95°C to 100 mL of water at 25°C in an insulated container

ANS: E PTS: 1 DIF: easy REF: 6.6

OBJ: Calculate using this relation between heat and specific heat. (Example 6. 5)

TOP: thermochemistry | heats of reaction KEY: calorimetry | measuring heats of reaction

MSC: general chemistry

1. Which of the following processes will result in the lowest final temperature of the metal–water mixture at equilibrium? The specific heat of cobalt is 0.421 J/(g · °C).

A)	the addition of 100 g of cobalt at 95°C to 80 mL of water at 25°C in an insulated container
B)	the addition of 100 g of cobalt at 95°C to 100 mL of water at 25°C in an insulated container
C)	the addition of 100 g of cobalt at 95°C to 40 mL of water at 25°C in an insulated container
D)	the addition of 100 g of cobalt at 95°C to 20 mL of water at 25°C in an insulated container
E)	the addition of 100 g of cobalt at 95°C to 60 mL of water at 25°C in an insulated container

ANS: B PTS: 1 DIF: moderate REF: 6.6

OBJ: Calculate using this relation between heat and specific heat. (Example 6. 5)

TOP: thermochemistry | heats of reaction KEY: calorimetry | measuring heats of reaction

MSC: general chemistry

1. A 170.0-g sample of metal at 79.00°C is added to 170.0 g of H₂O(l) at 14.00°C in an insulated container. The temperature rises to 16.19°C. Neglecting the heat capacity of the container, what is the specific heat of the metal? The specific heat of H₂O(l) is 4.18 J/(g · °C).

A)	4.18 J/(g · °C)
B)	120 J/(g · °C)
C)	0.146 J/(g · °C)
D)	–0.146 J/(g · °C)
E)	28.6 J/(g · °C)

ANS: C PTS: 1 DIF: difficult REF: 6.6

OBJ: Calculate using this relation between heat and specific heat. (Example 6. 5)

TOP: thermochemistry | heats of reaction KEY: calorimetry | specific heat

MSC: general chemistry

1. Exactly 105.2 J will raise the temperature of 10.0 g of a metal from 25.0°C to 60.0°C. What is the specific heat capacity of the metal?

A)	0.301 J/(g · °C)
B)	3.33 J/(g · °C)
C)	29.3 J/(g · °C)
D)	25.2 J/(g · °C)
E)	none of these

ANS: A PTS: 1 DIF: easy REF: 6.6

OBJ: Calculate using this relation between heat and specific heat. (Example 6. 5)

TOP: thermochemistry | heats of reaction KEY: calorimetry | specific heat

MSC: general chemistry

1. A 85.9-g piece of cobalt (s = 0.421 J/(g · °C)), initially at 263.1°C, is added to 116.2 g of a liquid, initially at 24.7°C, in an insulated container. The final temperature of the metal–liquid mixture at equilibrium is 50.8°C. What is the identity of the liquid? Neglect the heat capacity of the container.

A)	hexane (s = 2.27 J/(g · °C))
B)	methanol (s = 2.53 J/(g · °C))
C)	acetone (s = 2.15 J/(g · °C))
D)	ethanol (s = 2.43 J/(g · °C))
E)	water (s = 4.18 J/(g · °C))

ANS: B PTS: 1 DIF: moderate REF: 6.6

OBJ: Calculate using this relation between heat and specific heat. (Example 6. 5)

TOP: thermochemistry | heats of reaction KEY: calorimetry | specific heat

MSC: general chemistry

1. A 42.9-g sample of cobalt (s = 0.421 J/(g · °C)), initially at 157.2°C, is placed in an insulated vessel containing 120.9 g of water (s = 4.18 J/(g · °C)), initially at 19.2°C. Once equilibrium is reached, what is the final temperature of the metal–water mixture? Neglect the heat capacity of the vessel.

A)	24.0°C
B)	55.3°C
C)	14.1°C
D)	88.2°C
E)	31.8°C

ANS: A PTS: 1 DIF: difficult REF: 6.6

OBJ: Calculate using this relation between heat and specific heat. (Example 6. 5)

TOP: thermochemistry | heats of reaction KEY: calorimetry | specific heat

MSC: general chemistry

1. How much heat must be applied to a 18.3-g sample of iron (s = 0.449 J/(g · °C)) in order to raise its temperature from 23.8°C to 356.6°C?

A)	2.93 ´ 103 J
B)	2.73 ´ 103 J
C)	1.96 ´ 102 J
D)	6.09 ´ 103 J
E)	1.49 ´ 102 J

ANS: B PTS: 1 DIF: easy REF: 6.6

OBJ: Calculate using this relation between heat and specific heat. (Example 6. 5)

TOP: thermochemistry | heats of reaction KEY: calorimetry | specific heat

MSC: general chemistry

1. A 94.7-g sample of silver (s = 0.237 J/(g · °C)), initially at 348.25°C, is added to an insulated vessel containing 143.6 g of water (s = 4.18 J/(g · °C)), initially at 13.97°C. At equilibrium, the final temperature of the metal–water mixture is 22.63°C. How much heat was absorbed by the water? The heat capacity of the vessel is 0.244 kJ/°C.

A)	5.20 kJ
B)	3.09 kJ
C)	7.31 kJ
D)	9.12 kJ
E)	129 kJ

ANS: A PTS: 1 DIF: difficult REF: 6.6

OBJ: Calculate using this relation between heat and specific heat. (Example 6. 5)

TOP: thermochemistry | heats of reaction KEY: calorimetry | specific heat

MSC: general chemistry

1. A 500-cm³ sample of 1.0 M NaOH(aq) is added to 500 cm³ of 1.0 M HCl(aq) in a Styrofoam cup, and the solution is quickly stirred. The rise in temperature (DT₁) is measured. The experiment is repeated using 100 cm³ of each solution, and the rise in temperature (DT₂) is measured. What conclusion can you draw about DT₁ and DT₂?

HCl(aq) + NaOH(aq) ® H₂O(l) + NaCl(aq); DH° = –55.8 kJ

A)	DT2 is greater than DT1.
B)	DT2 is equal to DT1.
C)	DT1 is five times as large as DT2.
D)	DT1 is less than DT2.
E)	DT2 is five times as large as DT1.

ANS: B PTS: 1 DIF: difficult REF: 6.6

OBJ: Calculate using this relation between heat and specific heat. (Example 6. 5)

TOP: thermochemistry | heats of reaction

KEY: thermochemical equation | stoichiometry and heats of reaction

MSC: general chemistry

1. In a bomb calorimeter, reactions are carried out

A)	at 1 atm pressure and 0°C.
B)	at a constant pressure.
C)	at a constant volume.
D)	at a constant pressure and 25°C.
E)	at 1 atm pressure and 25°C.

ANS: C PTS: 1 DIF: easy REF: 6.6

OBJ: Define calorimeter. TOP: thermochemistry | heats of reaction

KEY: calorimetry | measuring heats of reaction MSC: general chemistry

1. A bomb calorimeter has a heat capacity of 2.47 kJ/K. When a 0.105-g sample of a certain hydrocarbon was burned in this calorimeter, the temperature increased by 2.14 K. Calculate the energy of combustion for 1 g of the hydrocarbon.

A)	–5.29 J/g
B)	J/g
C)	–0.120 J/g
D)	J/g
E)	–0.560 J/g

ANS: B PTS: 1 DIF: moderate REF: 6.6

OBJ: Calculate the enthalpy of reaction from calorimetric data (its temperature change and heat capacity). TOP: thermochemistry | heats of reaction

KEY: calorimetry | measuring heats of reaction MSC: general chemistry

1. When 7.13 g of methane (CH₄) is burned in a bomb calorimeter (heat capacity = 2.677 ´ 10³ J/°C), the temperature rises from 24.00 to 27.08°C. How much heat is absorbed by the calorimeter?

CH₄(g) + 2O₂(g) ® CO₂(g) + 2H₂O(l); DH° = –1283.8 kJ

A)	562 kJ
B)	3.66 ´ 103 kJ
C)	8.24 kJ
D)	571 kJ
E)	1.28 ´ 103 kJ

ANS: C PTS: 1 DIF: difficult REF: 6.6

OBJ: Calculate the enthalpy of reaction from calorimetric data (its temperature change and heat capacity). TOP: thermochemistry | heats of reaction

KEY: calorimetry | heat capacity MSC: general chemistry

1. When 0.0600 mol of HCl(aq) is reacted with 0.0600 mol of NaOH(aq) in 50.0 mL of water, the temperature of the solution increases by 15.1°C. What is the enthalpy of reaction for the following thermochemical equation?

HCl(aq) + NaOH(aq) ® NaCl(aq) + H₂O(l)

Assume that the heat capacity of the solution and calorimeter is 221.3 J/°C.

A)	–0.201 kJ
B)	55.8 kJ
C)	–3.35 kJ
D)	–55.8 kJ
E)	3.35 kJ

ANS: D PTS: 1 DIF: moderate REF: 6.6

OBJ: Calculate the enthalpy of reaction from calorimetric data (its temperature change and heat capacity). TOP: thermochemistry | heats of reaction

KEY: calorimetry | measuring heats of reaction MSC: general chemistry

1. When 50.0 mL of 1.20 M of HCl(aq) is combined with 50.0 mL of 1.30 M of NaOH(aq) in a coffee-cup calorimeter, the temperature of the solution increases by 8.01°C. What is the change in enthalpy for this balanced reaction?

HCl(aq) + NaOH(aq) ® NaCl(aq) + H₂O(l)

Assume that the solution density is 1.00 g/mL and the specific heat capacity of the solution is 4.18 J/g×°C.

A)	–55.8 kJ
B)	55.8 kJ
C)	51.5 kJ
D)	–51.5 kJ
E)	–26.8 kJ

ANS: A PTS: 1 DIF: moderate REF: 6.6

OBJ: Calculate the enthalpy of reaction from calorimetric data (its temperature change and heat capacity). TOP: thermochemistry | heats of reaction

1. Combustion of 7.21 g of liquid benzene (C₆H₆) causes a temperature rise of 50.3°C in a constant-pressure calorimeter that has a heat capacity of 5.99 kJ/°C. What is DH for the following reaction?

C₆H₆(l) + O₂(g) ® 6CO₂(g) + 3H₂O(l)

A)	–302 kJ/mol
B)	41.8 kJ/mol
C)	–41.8 kJ/mol
D)	–3.27 ´ 103 kJ/mol
E)	302 kJ/mol

ANS: D PTS: 1 DIF: moderate REF: 6.6

OBJ: Calculate the enthalpy of reaction from calorimetric data (its temperature change and heat capacity). TOP: thermochemistry | heats of reaction

KEY: calorimetry | measuring heats of reaction MSC: general chemistry

1. Given:

Pb(s) + PbO₂(s) + 2H₂SO₄(l) ® 2PbSO₄(s) + 2H₂O(l); DH° = –509.2 kJ

SO₃(g) + H₂O(l) ® H₂SO₄(l); DH° = –130. kJ

determine DH° for the following thermochemical equation.

Pb(s) + PbO₂(s) + 2SO₃(g) ® 2PbSO₄(s)

A)	3.77 ´ 103 kJ
B)	–521 kJ
C)	–3.77 ´ 103 kJ
D)	–639 kJ
E)	–769 kJ

ANS: E PTS: 1 DIF: moderate REF: 6.7

OBJ: Apply Hess’s law to obtain the enthalpy change for one reaction from the enthalpy changes of a number of other reactions. (Example 6.7)

TOP: thermochemistry | heats of reaction KEY: Hess’s law MSC: general chemistry

1. Given:

Fe₂O₃(s) + 3CO(g) ® 2Fe(s) + 3CO₂(g); DH° = –26.8 kJ

FeO(s) + CO(g) ® Fe(s) + CO₂(g); DH° = –16.5 kJ

determine DH° for the following thermochemical equation.

Fe₂O₃(s) + CO(g) ® 2FeO(s) + CO₂(g)

A)	6.2 kJ
B)	10.3 kJ
C)	22.7 kJ
D)	–10.3 kJ
E)	–43.3 kJ

ANS: A PTS: 1 DIF: moderate REF: 6.7

OBJ: Apply Hess’s law to obtain the enthalpy change for one reaction from the enthalpy changes of a number of other reactions. (Example 6.7)

TOP: thermochemistry | heats of reaction KEY: Hess’s law MSC: general chemistry

1. The overall chemical equation resulting from the sum of the following three steps is

2C(s) + 2H₂O(g) ® 2CO(g) + 2H₂(g)

CO(g) + H₂O(g) ® CO₂(g) + H₂(g)

CO(g) + 3H₂(g) ® CH₄(g) + H₂O(g)

A)	2C(s) + 2H2O(g) ® CO2(g) + CH4(g)
B)	2C(s) + 3H2O(g) ® CO(g) + CO2(g) + 3H2(g)
C)	2C(s) + H2O(g) + H2(g)® CO(g) + CH4(g)
D)	2CO(g) + 2H2(g) ® CH4(g) + CO2(g)
E)	2C(s) + CH4(g) + 3H2O(g) ® 3CO(g) + 5H2(g)

ANS: A PTS: 1 DIF: easy REF: 6.7

OBJ: Apply Hess’s law to obtain the overall reaction.

TOP: thermochemistry | heats of reaction

1. Using the following data, calculate the standard enthalpy of reaction for the coal gasification process 2C(s) + 2H₂O(g) ® CH₄(g) + CO₂(g).

C(s) + H₂O(g) ® CO(g) + H₂(g); DH° = +131.3 kJ

CO(g) + H₂O(g) ® CO₂(g) + H₂(g); DH° = –41.2 kJ

CO(g) + 3H₂(g) ® CH₄(g) + H₂O(g); DH° = –206.1 kJ

A)	–116.0 kJ
B)	378.6 kJ
C)	+15.3 kJ
D)	–157.2 kJ
E)	–378.6 kJ

ANS: C PTS: 1 DIF: moderate REF: 6.7

OBJ: Apply Hess’s law to obtain the enthalpy change for one reaction from the enthalpy changes of a number of other reactions. (Example 6.7)

TOP: thermochemistry | heats of reaction KEY: Hess’s law MSC: general chemistry

1. Given the following data, calculate the standard enthalpy of reaction for the conversion of buckminsterfullerene (C₆₀) into diamond:

C(graphite) ® C(diamond); DH° = +1.897 kJ

60C(graphite) ® C₆₀(fullerene); DH° = +2193 kJ

A)	-35 kJ
B)	35 kJ
C)	-2191 kJ
D)	2191 kJ
E)	38 kJ

ANS: A PTS: 1 DIF: moderate REF: 6.7

OBJ: Apply Hess’s law to obtain the enthalpy change for one reaction from the enthalpy changes of a number of other reactions. (Example 6.7)

TOP: thermochemistry | heats of reaction

1. Using two or more of the following,

N₂(g) + O₂(g) ® N₂O₃(s); DH° = 83.7 kJ

N₂(g) + O₂(g) ® 2NO(g); DH° = 180.4 kJ

N₂(g) + O₂(g) ® NO₂(g); DH° = 33.2 kJ

N₂(g) + H₂(g) ® NH₃(g); DH° = -45.9 kJ

determine DH° for the following reaction.

NO(g) + NO₂(g) ® N₂O₃(g)

A)	–39.7 kJ
B)	24.3 kJ
C)	–207.1 kJ
D)	39.7 kJ
E)	207.1 kJ

ANS: A PTS: 1 DIF: moderate REF: 6.7

OBJ: Apply Hess’s law to obtain the enthalpy change for one reaction from the enthalpy changes of a number of other reactions. (Example 6.7)

TOP: thermochemistry | heats of reaction

1. Consider the following changes at constant temperature and pressure:

H2O(s) ® H2O(l); DH1

H2O(l) ® H2O(g); DH2

H2O(g) ® H2O(s); DH3

Using Hess’s law, the sum DH₁ + DH₂ + DH₃ is

A)	equal to zero.
B)	sometimes greater than zero and sometimes less than zero.
C)	less than zero.
D)	cannot be determined without numerical values for DH.
E)	greater than zero.

ANS: A PTS: 1 DIF: moderate REF: 6.7

OBJ: Apply Hess’s law to obtain the enthalpy change for one reaction from the enthalpy changes of a number of other reactions. (Example 6.7)

TOP: thermochemistry | heats of reaction KEY: Hess’s law MSC: general chemistry

1. Given the following thermochemical data at 25°C and 1 atm pressure,

O₂(g) + 2B(s) ® B₂O₃(s); DH° = –1264 kJ

O₃(g) + 2B(s) ® B₂O₃(s); DH° = –1406 kJ

determine DH° for the following reaction at 25°C and 1 atm pressure.

3O₂(g) ® 2O₃(g)

A)	–980 kJ/mol
B)	+284 kJ/mol
C)	+980 kJ/mol
D)	–2670 kJ/mol
E)	–284 kJ/mol

ANS: B PTS: 1 DIF: moderate REF: 6.7

OBJ: Apply Hess’s law to obtain the enthalpy change for one reaction from the enthalpy changes of a number of other reactions. (Example 6.7)

TOP: thermochemistry | heats of reaction KEY: Hess’s law MSC: general chemistry

1. What is the standard enthalpy of formation of liquid methylamine (CH₃NH₂)?

C(s) + O₂(g) ® CO₂(g); DH° = –393.5 kJ

2H₂O(l) ® 2H₂(g) + O₂(g); DH° = 571.6 kJ

N₂(g) + O₂(g) ® NO₂(g); DH° = 33.10 kJ

4CH₃NH₂(l) + 13O₂(g) ® 4CO₂(g) + 4NO₂(g) + 10H₂O(l); DH° = –4110.4 kJ

A)	+3899.2 kJ/mol
B)	–3899.2 kJ/mol
C)	–47.3 kJ/mol
D)	+47.3 kJ/mol
E)	+3178.4 kJ

ANS: C PTS: 1 DIF: difficult REF: 6.7

OBJ: Apply Hess’s law to obtain the enthalpy change for one reaction from the enthalpy changes of a number of other reactions. (Example 6.7)

TOP: thermochemistry | heats of reaction KEY: Hess’s law MSC: general chemistry

1. Given that

O(g) + e^– ® O^–(g); DH = –142 kJ

O(g) + 2e^– ® O^2–(g); DH = 702 kJ

the enthalpy change for the reaction represented by the equation

O^–(g) + e^– ® O^2–(g) is

A)	0 kJ.
B)	–560 kJ.
C)	–844 kJ.
D)	844 kJ.
E)	560 kJ.

ANS: D PTS: 1 DIF: moderate REF: 6.7

OBJ: Apply Hess’s law to obtain the enthalpy change for one reaction from the enthalpy changes of a number of other reactions. (Example 6.7)

TOP: thermochemistry | heats of reaction KEY: Hess’s law MSC: general chemistry

1. Which of the following has a standard enthalpy of formation value of zero at 25°C?

A)	Cl(g)
B)	Cl2(l)
C)	Cl2(g)
D)	Cl(s)
E)	Cl2(s)

ANS: C PTS: 1 DIF: easy REF: 6.8

OBJ: Define standard state and reference form.

TOP: thermochemistry | heats of reaction KEY: standard enthalpies of formation

MSC: general chemistry

1. Which of the following has a standard enthalpy of formation value of zero at 25°C?

A)	O2(g)
B)	O3(g)
C)	O2(l)
D)	O(g)
E)	O2(s)

ANS: A PTS: 1 DIF: easy REF: 6.8

OBJ: Define standard state and reference form.

TOP: thermochemistry | heats of reaction KEY: standard enthalpies of formation

MSC: general chemistry

1. All of the following have a standard enthalpy of formation value of zero at 25°C except

A)	C(s).
B)	Ne(g).
C)	Fe(s).
D)	F2(g).
E)	CO(g).

ANS: E PTS: 1 DIF: easy REF: 6.8

OBJ: Define standard state and reference form.

TOP: thermochemistry | heats of reaction KEY: standard enthalpies of formation

MSC: general chemistry

1. Which substance has a standard enthalpy of formation equal to zero at 25°C?

A)	C2H6(g)
B)	Br2(g)
C)	Br2(l)
D)	Br2(s)
E)	C2H6(l)

ANS: C PTS: 1 DIF: easy REF: 6.8

OBJ: Define standard state and reference form.

TOP: thermochemistry | heats of reaction KEY: standard enthalpies of formation

MSC: general chemistry

1. Which of the following species does not have a standard enthalpy of formation equal to zero at 25°C?

A)	Cl2(l)
B)	N2(g)
C)	Fe(s)
D)	H+(aq)
E)	S8(s)

ANS: A PTS: 1 DIF: easy REF: 6.8

OBJ: Define standard state and reference form.

TOP: thermochemistry | heats of reaction KEY: standard enthalpies of formation

MSC: general chemistry

1. Which of the following has a standard enthalpy of formation value of zero at 25°C?

A)	C6H12O6(s)
B)	S8(s)
C)	FeSO4(s)
D)	H2O(l)
E)	FeSO4(aq)

ANS: B PTS: 1 DIF: easy REF: 6.8

OBJ: Define standard state and reference form.

TOP: thermochemistry | heats of reaction KEY: standard enthalpies of formation

MSC: general chemistry

1. Which of the following reactions corresponds to the thermochemical equation for the standard enthalpy of formation of solid lead (II) nitrate?

A)	Pb2+(aq) + 2NO3–(aq) ® Pb(NO3)2(s)
B)	Pb(OH)2(s) + 2HNO3(aq) ® Pb(NO3)2(s) + 2H2O(l)
C)	Pb(s) + N2(g) + 3O2(g) ® Pb(NO3)2(s)
D)	Pb(s) + 2HNO3(aq) ® Pb(NO3)2(s) + H2(g)
E)	Pb(s) + 2N(g) + 6O(g) ® Pb(NO3)2(s)

ANS: C PTS: 1 DIF: easy REF: 6.8

OBJ: Define standard enthalpy of formation.

TOP: thermochemistry | heats of reaction KEY: standard enthalpies of formation

MSC: general chemistry

1. The standard enthalpy change for which of the following processes corresponds to the standard enthalpy of formation of solid cesium fluoride?

A)	Cs(s) + F2(s) ® CsF(s)
B)	Cs(g) + F2(g) ® CsF(g)
C)	Cs(g) + F(g) ® CsF(s)
D)	Cs(s) + F2(g) ® CsF(s)
E)	Cs(s) + F2(s) ® CsF(g)

ANS: D PTS: 1 DIF: easy REF: 6.8

OBJ: Define standard enthalpy of formation.

TOP: thermochemistry | heats of reaction KEY: standard enthalpies of formation

MSC: general chemistry

1. The enthalpy change at 1 atm of which reaction corresponds to the standard enthalpy of formation of solid potassium bromate, KBrO₃?

A)	K(s) + Br(g) + 3O(g) ® KBrO3(s)
B)	K(g) + Br(g) + 3O(g) ® KBrO3(s)
C)	K(g) + Br2(g) + O2(g) ® KBrO3(s)
D)	K(s) + Br2(l) + O2(g) ® KBrO3(s)
E)	K(s) + Br2(g) + O2(g) ® KBrO3(s)

ANS: D PTS: 1 DIF: easy REF: 6.8

OBJ: Define standard enthalpy of formation.

TOP: thermochemistry | heats of reaction KEY: standard enthalpies of formation

MSC: general chemistry

1. For which of the following equations is the enthalpy change at 1 atm pressure equal to the standard enthalpy of formation of liquid formic acid, HCOOH?

A)	C(g) + 2H(g) + 2O(g) ® HCOOH(l)
B)	C(s) + 2H(g) + 2O(g) ® HCOOH(l)
C)	C(s) + H2(g) + O2(g) ® HCOOH(l)
D)	CO(g) + H2O(l) ® HCOOH(l)
E)	CO2(g) + H2(g) ® HCOOH(l)

ANS: C PTS: 1 DIF: easy REF: 6.8

OBJ: Define standard enthalpy of formation.

TOP: thermochemistry | heats of reaction KEY: standard enthalpies of formation

MSC: general chemistry

1. The balanced equation representing the standard enthalpy of formation reaction for NH₃(g) is

A)	N(g) + H2(g) ® NH3(g).
B)	N2(g) + 3H(g) ® NH3(g).
C)	N(g) + 3H(g) ® NH3(g).
D)	N2(g) + H2(g) ® NH3(g).
E)	N2(g) + H2(g) ® NH3(g).

ANS: D PTS: 1 DIF: easy REF: 6.8

OBJ: Define standard enthalpy of formation.

TOP: thermochemistry | heats of reaction

1. The enthalpy change at 1 atm of which reaction corresponds to the standard enthalpy of formation of solid magnesium nitrate, Mg(NO₃)₂?

A)	Mg2+(g) + 2NO3–(g) ® Mg(NO3)2(s)
B)	Mg(s) + N2(g) + 3O2(g) ® Mg(NO3)2(s)
C)	Mg(g) + 2N(g) + 6O(g) ® Mg(NO3)2(s)
D)	Mg(s) + N2(g) + 2O3(g) ® Mg(NO3)2(s)
E)	Mg2+(aq) + 2NO3–(aq) ® Mg(NO3)2(s)

ANS: B PTS: 1 DIF: easy REF: 6.8

OBJ: Define standard enthalpy of formation.

TOP: thermochemistry | heats of reaction KEY: standard enthalpies of formation

MSC: general chemistry

1. Which of the following reactions corresponds to the thermochemical equation for the standard enthalpy of formation of N,N-diethyl-m-toluamide, C₁₂H₁₇NO(l), the active ingredient in some insect repellents?

A)	12C(l) + 17H(l) + N(l) + O(l) ® C12H17NO(l)
B)	12C(g) + 17H(g) + N(g) + O(g) ® C12H17NO(g)
C)	12C(s) + 17H(g) + N(g) + O(g) ® C12H17NO(l)
D)	12C(s) + H2(g) + N2(g) + O2(g) ® C12H17NO(l)
E)	12C(g) + 17H(g) + N(g) + O(g) ® C12H17NO(l)

ANS: D PTS: 1 DIF: easy REF: 6.8

OBJ: Define standard enthalpy of formation.

TOP: thermochemistry | heats of reaction KEY: standard enthalpies of formation

MSC: general chemistry

1. What is DH° for the following phase change?

KCl(s) ® KCl(l)

Substance	DH°f (kJ/mol)
KCl(s)	–436.68
KCl(l)	–421.79

A)	858.47 kJ
B)	14.89 kJ
C)	–858.47 kJ
D)	–14.89 kJ
E)	0 kJ

ANS: B PTS: 1 DIF: moderate REF: 6.8

OBJ: Calculate the heat of a phase transition using standard enthalpies of formation for the different phases. (Example 6.8) TOP: thermochemistry | heats of reaction

KEY: standard enthalpies of formation MSC: general chemistry

1. A 34.5-L sample of a gaseous hydrocarbon, measured at 1.00 atm pressure and 25.0°C, is burned in excess oxygen, liberating 2.20 ´ 10³ kJ of heat at constant pressure. What is the identity of the hydrocarbon? (R = 0.0821 L · atm/(K · mol))

Substance	DH°f (kJ/mol)
CO2(g)	–393.5
H2O(l)	–285.8

A)	propylene (C3H6, DH°f = 20.41 kJ/mol)
B)	ethylene (C2H4, DH°f = 52.47 kJ/mol)
C)	acetylene (C2H2, DH°f = 226.73 kJ/mol)
D)	ethane (C2H6, DH°f = –84.68 kJ/mol)
E)	propane (C3H8, DH°f = –104.7 kJ/mol)

ANS: D PTS: 1 DIF: difficult REF: 6.8

OBJ: Calculate the heat (enthalpy) of reaction from the standard enthalpies of formation of the substances in the reaction. (Example 6.9)

TOP: thermochemistry | heats of reaction KEY: standard enthalpies of formation

MSC: general chemistry

1. What is DH° of the following reaction?

CO₂(g) + 2CH₄(g) ® C₃H₈(g) + O₂(g)

Substance	DH°f (kJ/mol)
CO2(g)	–393.5
CH4(g)	–74.9
C3H8(g)	–104.7

A)	–348.4 kJ
B)	–573.1 kJ
C)	438.6 kJ
D)	348.4 kJ
E)	–648.0 kJ

ANS: C PTS: 1 DIF: easy REF: 6.8

OBJ: Calculate the heat (enthalpy) of reaction from the standard enthalpies of formation of the substances in the reaction. (Example 6.9)

TOP: thermochemistry | heats of reaction KEY: standard enthalpies of formation

MSC: general chemistry

1. From the following information, determine DH°_f of malonic acid, CH₂(COOH)₂(s).

CH₂(COOH)₂(s) + 2O₂(g) ® 3CO₂(g) + 2H₂O(l); DH° = –861.0 kJ

Substance	DH°f (kJ/mol)
CO2(g)	–393.5
H2O(l)	–285.8

A)	2613 kJ
B)	891.1 kJ
C)	-1540.3 kJ
D)	-2613.1 kJ
E)	-891.1 kJ

ANS: E PTS: 1 DIF: moderate REF: 6.8

OBJ: Calculate the heat (enthalpy) of reaction from the standard enthalpies of formation of the substances in the reaction. (Example 6.9)

TOP: thermochemistry | heats of reaction KEY: standard enthalpies of formation

MSC: general chemistry

1. At 25°C, when 1.00 g of sulfur is burned at constant pressure in excess oxygen to give SO₂(g), 9.28 kJ of heat is liberated. What is the enthalpy of formation of SO₂(g)?

A)	9.28 kJ/mol
B)	–594 kJ/mol
C)	298 kJ/mol
D)	–9.28 kJ/mol
E)	–298 kJ/mol

ANS: E PTS: 1 DIF: difficult REF: 6.8

OBJ: Calculate the heat (enthalpy) of reaction from the standard enthalpies of formation of the substances in the reaction. (Example 6.9)

TOP: thermochemistry | heats of reaction KEY: standard enthalpies of formation

MSC: general chemistry

1. What is the standard enthalpy of formation of liquid butyraldehyde, CH₃CH₂CH₂CHO(l)?

CH₃CH₂CH₂CHO(l) + O₂(g) ® 4H₂O(l) + 4CO₂(g); DH° = –2471.8 kJ

Substance	DH°f (kJ/mol)
CO2(g)	–393.5
H2O(l)	–285.8

A)	–245.4 kJ/mol
B)	+245.4 kJ/mol
C)	–1792.5 kJ/mol
D)	–3151.1 kJ/mol
E)	+3151.1 kJ/mol

ANS: A PTS: 1 DIF: moderate REF: 6.8

OBJ: Calculate the heat (enthalpy) of reaction from the standard enthalpies of formation of the substances in the reaction. (Example 6.9)

TOP: thermochemistry | heats of reaction KEY: standard enthalpies of formation

MSC: general chemistry

1. What is DH° for the following reaction?

2C₂H₂(g) + 5O₂(g) ® 4CO₂(g) + 2H₂O(l)

Substance	DH°f (kJ/mol)
C2H2(g)	+226.7
CO2(g)	–393.5
H2O(l)	–285.8

A)	+1692.2 kJ
B)	–452.6 kJ
C)	–1692.2 kJ
D)	+2599.0 kJ
E)	–2599.0 kJ

ANS: E PTS: 1 DIF: moderate REF: 6.8

OBJ: Calculate the heat (enthalpy) of reaction from the standard enthalpies of formation of the substances in the reaction. (Example 6.9)

TOP: thermochemistry | heats of reaction KEY: standard enthalpies of formation

MSC: general chemistry

1. What is the standard enthalpy change for the combustion of gaseous propylene, C₃H₆?

C₃H₆(g) + O₂(g) ® 3CO₂(g) + 3H₂O(l)

Substance	DH°f (kJ/mol)
C3H6(g)	+20.4
CO2(g)	–393.5
H2O(l)	–285.8

A)	+2017.5 kJ
B)	–2058.3 kJ
C)	–658.9 kJ
D)	–2017.5 kJ
E)	+2058.3 kJ

ANS: B PTS: 1 DIF: moderate REF: 6.8

OBJ: Calculate the heat (enthalpy) of reaction from the standard enthalpies of formation of the substances in the reaction. (Example 6.9)

TOP: thermochemistry | heats of reaction KEY: standard enthalpies of formation

MSC: general chemistry

1. What is the standard enthalpy of formation of liquid n-butanol, CH₃CH₂CH₂CH₂OH?

CH₃CH₂CH₂CH₂OH(l) + 6O₂(g) ® 4CO₂(g) + 5H₂O(l); DH° = –2675 kJ

Substance	DH°f (kJ/mol)
CO2(g)	–393.5
H2O(l)	–285.8

A)	–328 kJ
B)	+3355 kJ
C)	–1996 kJ
D)	+328 kJ
E)	–3355 kJ

ANS: A PTS: 1 DIF: moderate REF: 6.8

OBJ: Calculate the heat (enthalpy) of reaction from the standard enthalpies of formation of the substances in the reaction. (Example 6.9)

TOP: thermochemistry | heats of reaction KEY: standard enthalpies of formation

MSC: general chemistry

1. At 25°C, the standard enthalpy of combustion of gaseous propane (C₃H₈) is –2219.0 kJ per mole of propane, and the standard enthalpy of combustion of gaseous propylene (C₃H₆) is –2058.3 kJ per mole of propylene. What is the standard enthalpy change for the following reaction at 25°C?

C₃H₆(g) + H₂(g) ® C₃H₈(g)

Substance	DH°f (kJ/mol)
CO2(g)	–393.5
H2O(l)	–285.8

A)	+104.7 kJ
B)	–20.4 kJ
C)	–125.1 kJ
D)	+160.7 kJ
E)	–160.7 kJ

ANS: C PTS: 1 DIF: moderate REF: 6.8

OBJ: Calculate the heat (enthalpy) of reaction from the standard enthalpies of formation of the substances in the reaction. (Example 6.9)

TOP: thermochemistry | heats of reaction KEY: standard enthalpies of formation

MSC: general chemistry

1. What is the standard enthalpy change for the combustion of liquid cyclopentane, C₅H₁₀?

2C₅H₁₀(l) + 15O₂(g) ® 10CO₂(g) + 10H₂O(l)

Substance	DH°f (kJ/mol)
C5H10(l)	–105.6
CO2(g)	–393.5
H2O(l)	–285.8

A)	+573.7 kJ
B)	–573.7 kJ
C)	+784.9 kJ
D)	–784.9 kJ
E)	–6581.8 kJ

ANS: E PTS: 1 DIF: moderate REF: 6.8

OBJ: Calculate the heat (enthalpy) of reaction from the standard enthalpies of formation of the substances in the reaction. (Example 6.9)

TOP: thermochemistry | heats of reaction KEY: standard enthalpies of formation

MSC: general chemistry

1. What is the standard enthalpy change for the following reaction?

3CH₄(g) + 4O₃(g) ® 3CO₂(g) + 6H₂O(g)

Substance	DH°f (kJ/mol)
CH4(g)	–74.87
O3(g)	+142.7
CO2(g)	–393.5
H2O(g)	–241.8

A)	–2285.1 kJ
B)	–2977.5 kJ
C)	+2977.5 kJ
D)	+2285.1 kJ
E)	–3426.5 kJ

ANS: B PTS: 1 DIF: moderate REF: 6.8

OBJ: Calculate the heat (enthalpy) of reaction from the standard enthalpies of formation of the substances in the reaction. (Example 6.9)

TOP: thermochemistry | heats of reaction KEY: standard enthalpies of formation

MSC: general chemistry

1. What is the standard enthalpy change for the following reaction?

N₂H₄(l) + 2NO₂(g) ® 2N₂O(g) + 2H₂O(l)

Substance	DH°f (kJ/mol)
N2H4(l)	+50.6
NO2(g)	+33.1
N2O(g)	+82.1
H2O(l)	–285.8

A)	–290.6 kJ
B)	–524.2 kJ
C)	–119.7 kJ
D)	+290.6 kJ
E)	+119.7 kJ

ANS: B PTS: 1 DIF: moderate REF: 6.8

OBJ: Calculate the heat (enthalpy) of reaction from the standard enthalpies of formation of the substances in the reaction. (Example 6.9)

TOP: thermochemistry | heats of reaction KEY: standard enthalpies of formation

MSC: general chemistry

1. What is the standard enthalpy of formation of liquid diethylamine, (CH₃CH₂)₂NH?

N₂O₅(g) + 8CH₄(g) ® 2(CH₃CH₂)₂NH(l) + 5H₂O(l); DH° = –1103 kJ

Substance	DH°f (kJ/mol)
N2O5(g)	+11.3
CH4(g)	–74.9
H2O(l)	–285.8

A)	–131 kJ/mol
B)	–421 kJ/mol
C)	+131 kJ/mol
D)	–1452 kJ/mol
E)	+421 kJ/mol

ANS: A PTS: 1 DIF: moderate REF: 6.8

OBJ: Calculate the heat (enthalpy) of reaction from the standard enthalpies of formation of the substances in the reaction. (Example 6.9)

TOP: thermochemistry | heats of reaction KEY: standard enthalpies of formation

MSC: general chemistry

1. The standard enthalpies of formation of various iodine species are as follows:

Substance	DH°f (kJ/mol)
I(g)	+107
I2(g)	+21
HI(g)	+26

What additional information is needed to calculate the standard enthalpy change of the following reaction?

H₂(g) + I₂(g) ® 2HI(g)

A)	none, because the answer is 2 times 26 kJ/mol
B)	the enthalpy of formation of I–(g) and H+(g)
C)	the enthalpy of formation of solid iodine
D)	none, because the enthalpy of formation of I2(g) and HI(g) are given and the enthalpy of elemental hydrogen is zero
E)	the enthalpy of formation of gaseous hydrogen

ANS: D PTS: 1 DIF: moderate REF: 6.8

OBJ: Calculate the heat (enthalpy) of reaction from the standard enthalpies of formation of the substances in the reaction. (Example 6.9)

TOP: thermochemistry | heats of reaction KEY: standard enthalpies of formation

MSC: general chemistry

1. What is the standard enthalpy of formation of MgCO₃(s)?

MgO(s) + CO₂(g) ® MgCO₃(s); DH° = –100.7 kJ

Substance	DH°f (kJ/mol)
MgO(s)	–601.6
CO2(g)	–393.5

A)	107.4 kJ
B)	–308.8 kJ
C)	–894.4 kJ
D)	–1095.8 kJ
E)	894.4 kJ

ANS: D PTS: 1 DIF: moderate REF: 6.8

OBJ: Calculate the heat (enthalpy) of reaction from the standard enthalpies of formation of the substances in the reaction. (Example 6.9)

TOP: thermochemistry | heats of reaction KEY: standard enthalpies of formation

MSC: general chemistry

1. From the following information, determine the enthalpy of formation of C₂H₄(g).

C₂H₄(g) ® C(s) + H₂(g); DH = –26.2 kJ

A)	–26.2 kJ/mol
B)	26.2 kJ/mol
C)	104.8 kJ/mol
D)	–52.4 kJ/mol
E)	52.4 kJ/mol

ANS: E PTS: 1 DIF: easy REF: 6.8

OBJ: Calculate the heat (enthalpy) of reaction from the standard enthalpies of formation of the substances in the reaction. (Example 6.9)

TOP: thermochemistry | heats of reaction KEY: standard enthalpies of formation

MSC: general chemistry

1. Calculate the change in enthalpy when 52.0 g of solid chromium at 25°C and 1 atm pressure is oxidized. (DH°_f for Cr₂O₃(s) is –1135 kJ/mol.)

4Cr(s) + 3O₂(g) ® 2Cr₂O₃(s)

A)	–1135 kJ
B)	–284 kJ
C)	–568 kJ
D)	+1135 kJ
E)	+568 kJ

ANS: C PTS: 1 DIF: moderate REF: 6.8

OBJ: Calculate the heat (enthalpy) of reaction from the standard enthalpies of formation of the substances in the reaction. (Example 6.9)

TOP: thermochemistry | heats of reaction KEY: standard enthalpies of formation

MSC: general chemistry

1. Which of the following is/are correct about fossil fuels?

	1.	Anthracite coal is pure, amorphous carbon.
	2.	Purified natural gas is a mixture of primarily methane and small amounts of ethane, propane, and butane.
	3.	Gasoline obtained from petroleum primarily contains the hydrocarbon octane (C8H18).

A)	1 only
B)	2 only
C)	3 only
D)	1, 2 and 3
E)	none

ANS: B PTS: 1 DIF: easy REF: 6.9

OBJ: List the three major fossil fuels. TOP: thermochemistry | heats of reaction

1. Which of the following is not a fuel–oxidizer mixture used in rockets?

A)	kerosene–oxygen
B)	hydrogen–oxygen
C)	octane–oxygen
D)	aluminum–ammonium perchlorate
E)	hydrazine–dinitrogen tetroxide

ANS: C PTS: 1 DIF: easy REF: 6.9

OBJ: Describe some fuel-oxidizer systems used in rockets.

TOP: thermochemistry | heats of reaction MSC: general chemistry

Chapter 7 – Quantum Theory of the Atom

1. What is the wavelength of a photon having a frequency of 64.6 THz? (1 THz = 10¹⁵ Hz, c = 3.00 ´ 10⁸ m/s, h = 6.63 ´ 10^–34 J × s)

A)	0.215 nm
B)	4.28 ´ 10–23 nm
C)	1.28 ´ 10–14 nm
D)	4.64 nm
E)	4.64 ´ 1015 nm

ANS: D PTS: 1 DIF: easy REF: 7.1

OBJ: Relate the wavelength, frequency, and speed of light. (Examples 7.1 and 7.2)

TOP: atomic theory | light KEY: electromagnetic radiation

MSC: general chemistry

1. Which of the following is/are true about electromagnetic radiation?

	1.	Wavelength is inversely proportional to frequency.
	2.	Frequency has units of s-1 or Hz.
	3.	Waves of different wavelengths travel at different speeds in a vacuum.

A)	1 only
B)	2 only
C)	3 only
D)	1 and 2
E)	1, 2, and 3

ANS: D PTS: 1 DIF: easy REF: 7.1

OBJ: Relate the wavelength, frequency, and speed of light. (Examples 7.1 and 7.2)

TOP: atomic theory | light

1. What is the wavelength of a photon having a frequency of Hz? (, )

A)	667 nm
B)	nm
C)	nm
D)	0.0895 nm
E)	nm

ANS: A PTS: 1 DIF: easy REF: 7.1

OBJ: Relate the wavelength, frequency, and speed of light. (Examples 7.1 and 7.2)

TOP: atomic theory | light KEY: electromagnetic radiation

MSC: general chemistry

1. What is the frequency of a photon having a wavelength of 954.9 nm? (, )

A)	3.14 ´ 10–4 Hz
B)	1.44 ´ 1027 Hz
C)	3.14 ´ 1014 Hz
D)	2.08 ´ 10–37 Hz
E)	2.08 ´ 10–19 Hz

ANS: C PTS: 1 DIF: easy REF: 7.1

OBJ: Relate the wavelength, frequency, and speed of light. (Examples 7.1 and 7.2)

TOP: atomic theory | light KEY: electromagnetic radiation

MSC: general chemistry

1. Which of the following statements is incorrect?

A)	As the energy of a photon increases, its frequency decreases.
B)	As the wavelength of a photon increases, its energy decreases.
C)	The product of wavelength and frequency of electromagnetic radiation is a constant.
D)	As the wavelength of a photon increases, its frequency decreases.
E)	As the frequency of a photon increases, its wavelength decreases.

ANS: A PTS: 1 DIF: easy REF: 7.1

OBJ: Relate the wavelength, frequency, and speed of light. (Examples 7.1 and 7.2)

TOP: atomic theory | light KEY: electromagnetic radiation

MSC: general chemistry

1. Which type of electromagnetic radiation has the shortest wavelength?

A)	red light
B)	x rays
C)	microwaves
D)	gamma rays
E)	blue light

ANS: D PTS: 1 DIF: easy REF: 7.1

OBJ: Describe the different regions of the electromagnetic spectrum.

TOP: atomic theory | light KEY: electromagnetic radiation

MSC: general chemistry

1. Which type of electromagnetic radiation has the highest frequency?

A)	microwaves
B)	visible
C)	radio waves
D)	infrared
E)	ultraviolet

ANS: E PTS: 1 DIF: easy REF: 7.1

OBJ: Describe the different regions of the electromagnetic spectrum.

TOP: atomic theory | light KEY: electromagnetic radiation

MSC: general chemistry

1. Rank the following regions of the electromagnetic spectrum in order of decreasing frequency.

X rays, Microwaves, Infrared, Ultraviolet

A)	infrared, microwaves, ultraviolet, x rays
B)	x rays, microwaves, infrared, ultraviolet
C)	microwaves, infrared, ultraviolet, x rays
D)	microwaves, ultraviolet, infrared, x rays
E)	x rays, ultraviolet, infrared, microwaves

ANS: E PTS: 1 DIF: easy REF: 7.1

OBJ: Describe the different regions of the electromagnetic spectrum.

TOP: atomic theory | light KEY: electromagnetic radiation

MSC: general chemistry

1. A photon of red light has a ____ frequency and a ____ wavelength than a photon of blue light.

A)	lower, longer
B)	higher, shorter
C)	lower, shorter
D)	higher, longer
E)	lower, lower

ANS: A PTS: 1 DIF: moderate REF: 7.1

OBJ: Describe the different regions of the electromagnetic spectrum.

TOP: atomic theory | light KEY: electromagnetic radiation

MSC: general chemistry

1. Based on the photoelectric effect, Einstein proposed the idea that

A)	the energy of a single particle or photon of light is inversely proportional to its frequency.
B)	the wavelength of light is inversely proportional to its frequency.
C)	particles can show characteristics of waves under certain experimental conditions.
D)	the energy of an object is proportional to its mass.
E)	light has particle-like properties.

ANS: E PTS: 1 DIF: easy REF: 7.2

OBJ: Describe the photoelectric effect. TOP: atomic theory | light

1. When a particular metal is illuminated with photons, one electron is observed for each absorbed photon. What effect would decreasing the wavelength and number of photons have on the electrons leaving the surface?

A)	There would be more electrons leaving the surface.
B)	They would have higher kinetic energy.
C)	The electron velocity would be lower.
D)	The kinetic energy of the electrons would be lower.
E)	Two photons might be required to eject the electrons.

ANS: B PTS: 1 DIF: difficult REF: 7.2

OBJ: Describe the photoelectric effect. TOP: atomic theory | light

KEY: quantum effects and photons | photoelectric effect MSC: general chemistry

1. A laser emits photons having an energy of 3.74 ´ 10^–19 J. What color would be expected for the light emitted by this laser? (c = 3.00 ´ 10⁸ m/s, h = 6.63 ´ 10^–34 J × s)

A)	yellow to orange
B)	orange to red
C)	green
D)	violet
E)	blue

ANS: C PTS: 1 DIF: moderate REF: 7.2

OBJ: Calculate the energy of a photon from its frequency or wavelength. (Example 7.3)

TOP: atomic theory | light KEY: electromagnetic radiation

MSC: general chemistry

1. A light emitting diode (L.E.D.) emits photons with an energy of J. What is the energy per mole of photons emitted?

A)	J/mol
B)	J/mol
C)	J/mol
D)	J/mol
E)	J/mol

ANS: A PTS: 1 DIF: moderate REF: 7.2

OBJ: Calculate the energy of a mole of photons from its energy per photon.

TOP: atomic theory | light

1. Which type of electromagnetic radiation has the highest energy?

A)	radio waves
B)	x rays
C)	red light
D)	blue light
E)	gamma rays

ANS: E PTS: 1 DIF: easy REF: 7.2

OBJ: Calculate the energy of a photon from its frequency or wavelength. (Example 7.3)

TOP: atomic theory | light

KEY: quantum effects and photons | Planck’s quantization of energy

MSC: general chemistry

1. What is the energy of a photon of electromagnetic radiation with a wavelength of 877.4 nm? ()

A)	J
B)	J
C)	J
D)	J
E)	J

ANS: A PTS: 1 DIF: easy REF: 7.2

OBJ: Calculate the energy of a photon from its frequency or wavelength. (Example 7.3)

TOP: atomic theory | light

KEY: quantum effects and photons | Planck’s quantization of energy

MSC: general chemistry

1. What is the energy of a photon of electromagnetic radiation with a frequency of Hz? ()

A)	J
B)	J
C)	J
D)	J
E)	J

ANS: E PTS: 1 DIF: easy REF: 7.2

OBJ: Calculate the energy of a photon from its frequency or wavelength. (Example 7.3)

TOP: atomic theory | light

KEY: quantum effects and photons | Planck’s quantization of energy

MSC: general chemistry

1. What is the wavelength of a photon that has an energy of J? ()

A)	nm
B)	nm
C)	0.843 nm
D)	nm
E)	nm

ANS: C PTS: 1 DIF: easy REF: 7.2

OBJ: Calculate the energy of a photon from its frequency or wavelength. (Example 7.3)

TOP: atomic theory | light

KEY: quantum effects and photons | Planck’s quantization of energy

MSC: general chemistry

1. What is the frequency of a photon having an energy of ()

A)
B)
C)
D)
E)

ANS: C PTS: 1 DIF: easy REF: 7.2

OBJ: Calculate the energy of a photon from its frequency or wavelength. (Example 7.3)

TOP: atomic theory | light

KEY: quantum effects and photons | Planck’s quantization of energy

MSC: general chemistry

1. What is the wavelength of photons that have molar energy of 479 kJ/mol? ()

A)
B)
C)
D)
E)

ANS: C PTS: 1 DIF: moderate REF: 7.2

OBJ: Calculate the energy of a photon from its frequency or wavelength. (Example 7.3)

TOP: atomic theory | light

KEY: quantum effects and photons | Planck’s quantization of energy

MSC: general chemistry

1. What is the frequency of photons that have molar energy of 525 kJ/mol? ()

A)
B)
C)
D)
E)

ANS: B PTS: 1 DIF: moderate REF: 7.2

OBJ: Calculate the energy of a photon from its frequency or wavelength. (Example 7.3)

TOP: atomic theory | light

KEY: quantum effects and photons | Planck’s quantization of energy

MSC: general chemistry

1. What is the energy per mole of photons with a wavelength of 976.9 nm? ()

A)
B)
C)
D)
E)

ANS: E PTS: 1 DIF: moderate REF: 7.2

OBJ: Calculate the energy of a photon from its frequency or wavelength. (Example 7.3)

TOP: atomic theory | light

KEY: quantum effects and photons | Planck’s quantization of energy

MSC: general chemistry

1. What is the energy per mole of photons having a frequency of ()

A)
B)
C)
D)
E)

ANS: B PTS: 1 DIF: moderate REF: 7.2

OBJ: Calculate the energy of a photon from its frequency or wavelength. (Example 7.3)

TOP: atomic theory | light

KEY: quantum effects and photons | Planck’s quantization of energy

MSC: general chemistry

1. Which of the following scientists first postulated that the sharp lines in the emission spectra of elements were caused by electrons going from high-energy levels to low-energy levels?

A)	Rutherford
B)	Pauli
C)	Hund
D)	de Broglie
E)	Bohr

ANS: E PTS: 1 DIF: easy REF: 7.3

OBJ: State the postulates of Bohr’s theory of the hydrogen atom.

TOP: atomic theory | light KEY: Bohr theory | Bohr’s postulates

MSC: general chemistry

1. Which of the following is/are correct postulates of Bohr’s theory of the hydrogen atom ?

	1.	The energy of an electron in an atom is quantized (i.e. only specific energy values are possible).
	2.	The principal quantum number (n), specifies each unique energy level.
	3.	An electron transition from a lower energy level to a higher energy level results in an emission of a photon of light.

A)	1 only
B)	2 only
C)	3 only
D)	1 and 2
E)	1, 2, and 3

ANS: D PTS: 1 DIF: easy REF: 7.3

OBJ: State the postulates of Bohr’s theory of the hydrogen atom.

TOP: atomic theory | light

1. Whose postulates account for the line spectrum of an atom?

A)	Thomson
B)	de Broglie
C)	Heisenberg
D)	Rutherford
E)	Bohr

ANS: E PTS: 1 DIF: easy REF: 7.3

OBJ: State the postulates of Bohr’s theory of the hydrogen atom.

TOP: atomic theory | light KEY: Bohr theory | Bohr’s postulates

MSC: general chemistry

1. Who postulated that energy is radiated only when an electron falls from a higher-energy level to a lower-energy level?

A)	Bohr
B)	Heisenberg
C)	Rutherford
D)	Einstein
E)	Millikan

ANS: A PTS: 1 DIF: easy REF: 7.3

OBJ: State the postulates of Bohr’s theory of the hydrogen atom.

TOP: atomic theory | light KEY: Bohr theory | Bohr’s postulates

MSC: general chemistry

1. In Bohr’s atomic theory, when an electron moves from one energy level to another energy level more distant from the nucleus,

A)	energy is absorbed.
B)	light is emitted.
C)	energy is emitted.
D)	no change in energy occurs.
E)	none of these

ANS: A PTS: 1 DIF: easy REF: 7.3

OBJ: State the postulates of Bohr’s theory of the hydrogen atom.

TOP: atomic theory | light KEY: Bohr theory | Bohr’s postulates

MSC: general chemistry

1. When an electron in an atom makes a transition from n = 6 to n = 4, which of the following statements is/are correct?

I.	Energy is emitted.
II.	Energy is absorbed.
III.	The electron loses energy.
IV.	The electron gains energy.
V.	The electron cannot make this transition.

A)	I and III
B)	I and IV
C)	II and IV
D)	II and III
E)	III

ANS: A PTS: 1 DIF: easy REF: 7.3

OBJ: Relate the energy of a photon to the associated energy levels of an atom.

TOP: atomic theory | light

1. From the Bohr model of the hydrogen atom, we can conclude that the energy required to excite an electron from n = 5 to n = 6 is ____ the energy required to excite an electron from n = 4 to 5.

A)	less than
B)	greater than
C)	equal to
D)	either equal to or less than
E)	either equal to or greater than

ANS: A PTS: 1 DIF: moderate REF: 7.3

OBJ: Relate the energy of a photon to the associated energy levels of an atom.

TOP: atomic theory | light

1. What is the wavelength of light emitted when the electron in a hydrogen atom undergoes a transition from level ( )

A)
B)
C)
D)
E)

ANS: A PTS: 1 DIF: moderate REF: 7.3

OBJ: Determine the wavelength or frequency of a hydrogen atom transition. (Example 7.4)

TOP: atomic theory | light KEY: Bohr theory | atomic line spectra

MSC: general chemistry

1. What is the frequency of light emitted when the electron in a hydrogen atom undergoes a transition from level ( )

A)
B)
C)
D)
E)

ANS: E PTS: 1 DIF: moderate REF: 7.3

OBJ: Determine the wavelength or frequency of a hydrogen atom transition. (Example 7.4)

TOP: atomic theory | light KEY: Bohr theory | atomic line spectra

MSC: general chemistry

1. The electron in a hydrogen atom, originally in level , undergoes a transition to a lower level by emitting a photon of wavelength 1006 nm. What is the final level of the electron? (

A)	3
B)	4
C)	7
D)	8
E)	1

ANS: A PTS: 1 DIF: difficult REF: 7.3

OBJ: Determine the wavelength or frequency of a hydrogen atom transition. (Example 7.4)

TOP: atomic theory | light KEY: Bohr theory | atomic line spectra

MSC: general chemistry

1. Consider the following energy-level diagram for a particular electron in an atom.

Based on this diagram, which of the following statements is incorrect?

A)	The wavelength of a photon emitted by the electron jumping from level 2 to level 1 is given by .
B)	If the electron is in level 1, it may jump to level 2 by absorbing a photon with energy of DE.
C)	If the electron is in level 1, it may jump to level 2 by absorbing any photon having energy of at least DE.
D)	We would observe an electron jumping from level 2 to level 1 as a single line in a line spectrum.
E)	If the electron is in level 2, it may jump to level 1 by emitting a photon with energy of |DE|.

ANS: C PTS: 1 DIF: difficult REF: 7.3

OBJ: Describe the difference between emission and absorption of light by an atom.

TOP: atomic theory | light KEY: Bohr theory | Bohr’s postulates

MSC: general chemistry

1. The contribution for which de Broglie is best remembered in modern science is

A)	his statement that no electron can have identical values for all four quantum numbers.
B)	his proposal that particles of matter should be associated with wavelike behavior.
C)	his statement that an electron can exist in an atom only in discrete energy levels.
D)	his statement that elements show periodic repetition of properties.
E)	his statement that electrons occupy all the orbitals of a given sublevel singly before pairing begins.

ANS: B PTS: 1 DIF: easy REF: 7.4

OBJ: State the de Broglie relation. TOP: atomic theory | quantum mechanics

KEY: de Broglie relation MSC: general chemistry

1. Which of the following statements concerning quantum mechanics is/are true?

	1.	The behavior of submicroscopic particles can sometimes be described as waves.
	2.	Quantum mechanics limits us to making statistical statements about the location of an electron in an atom.
	3.	The uncertainty principle is important only for particles of very small mass, such as the electron.

A)	1 only
B)	2 only
C)	3 only
D)	2 and 3
E)	1, 2, and 3

ANS: E PTS: 1 DIF: easy REF: 7.4

OBJ: Define Quantum mechanics. TOP: atomic theory | quantum mechanics

1. What is the wavelength of a 149-g baseball traveling at 97.2 mph? ()

A)
B)
C)
D)
E)

ANS: B PTS: 1 DIF: moderate REF: 7.4

OBJ: Calculate the wavelength of a moving particle. (Example 7.5)

TOP: atomic theory | quantum mechanics

KEY: de Broglie relation MSC: general chemistry

1. What is the wavelength of an electron traveling at 7.59% of the speed of light? ()

A)
B)
C)
D)
E)

ANS: C PTS: 1 DIF: moderate REF: 7.4

OBJ: Calculate the wavelength of a moving particle. (Example 7.5)

TOP: atomic theory | quantum mechanics

KEY: de Broglie relation MSC: general chemistry

1. If the location of a particular electron can be measured only to a precision of 0.011 nm, what is the minimum uncertainty in the electron’s velocity? (

)

A)
B)
C)
D)
E)

ANS: A PTS: 1 DIF: moderate REF: 7.4

OBJ: State Heisenberg’s uncertainty principle.

TOP: atomic theory | quantum mechanics

KEY: wave functions | Heisenberg’s uncertainty principle MSC: general chemistry

1. If the x-component of the velocity of an electron can be measured only to a precision of , what is the minimum uncertainty of the position of the electron in the x-direction? ( )

A)
B)
C)
D)
E)

ANS: B PTS: 1 DIF: moderate REF: 7.4

OBJ: State Heisenberg’s uncertainty principle.

TOP: atomic theory | quantum mechanics

KEY: wave functions | Heisenberg’s uncertainty principle MSC: general chemistry

1. Which of the following statements is a valid conclusion from the Heisenberg uncertainty principle?

A)	The square of the wave function is proportional to the probability of finding a particle in space.
B)	Particles can exhibit wavelike behavior.
C)	The orbits proposed by Bohr’s model of the atom are correct.
D)	An electron in a 2p orbital is always closer to the nucleus than an electron in a 3p orbital.
E)	The act of measuring a particle’s position changes its momentum, and vice versa.

ANS: E PTS: 1 DIF: moderate REF: 7.4

OBJ: State Heisenberg’s uncertainty principle.

TOP: atomic theory | quantum mechanics

KEY: wave functions | Heisenberg’s uncertainty principle MSC: general chemistry

1. Which of the following statements is incorrect concerning the wave function?

A)	The wave function of a particle is a solution to the Schrödinger equation.
B)	For an electron in an atom, the square of the wave function decreases rapidly as the distance from the nucleus increases.
C)	The square of the wave function is proportional to the probability of finding the particle in a region of space.
D)	The value of the wave function gives the location of the particle.
E)	The wave function for an electron in an atom is called an atomic orbital.

ANS: D PTS: 1 DIF: moderate REF: 7.4

OBJ: Relate the wave function for an electron to the probability of finding it at a location in space. TOP: atomic theory | quantum mechanics

KEY: wave functions MSC: general chemistry

1. The square of the wave function, y², of an electron in an atom

A)	is inversely proportional to the distance between the electron and the nucleus.
B)	specifies the momentum of the electron.
C)	describes the energy of the electron.
D)	is proportional to the velocity of the electron.
E)	gives the probability of finding the electron in a region of space.

ANS: E PTS: 1 DIF: easy REF: 7.4

OBJ: Relate the wave function for an electron to the probability of finding it at a location in space. TOP: atomic theory | quantum mechanics

KEY: wave functions MSC: general chemistry

1. A radial probability plot for an electron in an atom, like that shown below,

A)	specifies the probable speed of the electron at a given radius from the nucleus.
B)	specifies the probable momentum of the electron at a given radius from the nucleus.
C)	describes the probable energy of the electron at a given radius from the nucleus.
D)	gives the probability of finding one electron near another at a given radius from the nucleus.
E)	gives the probability of finding the electron at a given radius from the nucleus.

ANS: E PTS: 1 DIF: easy REF: 7.4

OBJ: Relate the wave function for an electron to the probability of finding it at a location in space. TOP: atomic theory | quantum mechanics

1. The number of orbitals having a given value of l is equal to

A)	2n + 1.
B)	2l + 1.
C)	n + ml.
D)	2ml + 1.
E)	l + ml.

ANS: B PTS: 1 DIF: easy REF: 7.5

OBJ: Define atomic orbital. TOP: atomic theory | quantum mechanics

KEY: quantum numbers MSC: general chemistry

1. Which quantum number distinguishes the different shapes of the orbitals?

A)	n
B)	ml
C)	l
D)	ms
E)	any of these

ANS: C PTS: 1 DIF: easy REF: 7.5

OBJ: Define each of the quantum numbers for an atomic orbital.

TOP: atomic theory | quantum mechanics

KEY: quantum numbers | angular momentum quantum number MSC: general chemistry

1. The angular momentum quantum number is best associated with the

A)	shape of the orbital.
B)	number of orbitals in a subshell.
C)	energy of the orbital.
D)	orientation in space of an orbital.
E)	none of the above

ANS: A PTS: 1 DIF: easy REF: 7.5

OBJ: Define each of the quantum numbers for an atomic orbital.

TOP: atomic theory | quantum mechanics

KEY: quantum numbers | angular momentum quantum number MSC: general chemistry

1. Which of the following sets of quantum numbers (n, l, m_l, m_s) refers to a 3d orbital?

A)	2 1 0 +
B)	5 4 3 +
C)	4 2 1 –
D)	4 3 1 –
E)	3 2 1 –

ANS: E PTS: 1 DIF: easy REF: 7.5

OBJ: Define each of the quantum numbers for an atomic orbital.

TOP: atomic theory | quantum mechanics KEY: quantum numbers

MSC: general chemistry

1. What is the value of the angular momentum quantum number for an electron in a 5d orbital?

A)	0
B)	4
C)	1
D)	2
E)	3

ANS: D PTS: 1 DIF: easy REF: 7.5

OBJ: Define each of the quantum numbers for an atomic orbital.

TOP: atomic theory | quantum mechanics

KEY: quantum numbers | angular momentum quantum number MSC: general chemistry

1. A possible value of the magnetic quantum number m_l for a 5p electron is

A)	1.
B)	–4.
C)	–5.
D)	6.
E)	3.

ANS: A PTS: 1 DIF: easy REF: 7.5

OBJ: Define each of the quantum numbers for an atomic orbital.

TOP: atomic theory | quantum mechanics

KEY: quantum numbers | magnetic quantum number MSC: general chemistry

1. All the following statements about the quantum numbers are true except

A)	ml has 2l + 1 possible values.
B)	n may take integral values from 1 to ¥.
C)	ml may take integral values of +l to –l, including zero.
D)	l may take integral values from 1 to n – 1.
E)	ms may take only the values of and .

ANS: D PTS: 1 DIF: easy REF: 7.5

OBJ: State the rules for the allowed values for each quantum number.

TOP: atomic theory | quantum mechanics KEY: quantum numbers

MSC: general chemistry

1. How many values are there for the magnetic quantum number when the value of the angular momentum quantum number is 4?

A)	14
B)	9
C)	1
D)	4
E)	15

ANS: B PTS: 1 DIF: easy REF: 7.5

OBJ: State the rules for the allowed values for each quantum number.

TOP: atomic theory | quantum mechanics

KEY: quantum numbers | magnetic quantum number MSC: general chemistry

1. An orbital with the quantum numbers may be found in which subshell?

A)	3f
B)	3d
C)	3p
D)	3g
E)	3s

ANS: B PTS: 1 DIF: easy REF: 7.5

OBJ: State the rules for the allowed values for each quantum number.

TOP: atomic theory | quantum mechanics KEY: quantum numbers

MSC: general chemistry

1. What is the value of the principal quantum number for an electron in a 1s orbital?

A)	–1
B)
C)	1
D)
E)	0

ANS: C PTS: 1 DIF: easy REF: 7.5

OBJ: State the rules for the allowed values for each quantum number.

TOP: atomic theory | quantum mechanics

KEY: quantum numbers | principle quantum number MSC: general chemistry

1. What is the value of the spin quantum number for an electron in a 3p orbital?

A)	3
B)	1
C)	either or
D)
E)

ANS: C PTS: 1 DIF: easy REF: 7.5

OBJ: State the rules for the allowed values for each quantum number.

TOP: atomic theory | quantum mechanics

KEY: quantum numbers | spin quantum number MSC: general chemistry

1. Which of the following subshells does not exist?

A)	6g
B)	3f
C)	3p
D)	2s
E)	4d

ANS: B PTS: 1 DIF: moderate REF: 7.5

OBJ: State the rules for the allowed values for each quantum number.

TOP: atomic theory | quantum mechanics KEY: quantum numbers

MSC: general chemistry

1. The number of orbitals in a p subshell is

A)	3.
B)	1.
C)	7.
D)	2.
E)	5.

ANS: A PTS: 1 DIF: easy REF: 7.5

OBJ: State the rules for the allowed values for each quantum number.

TOP: atomic theory | quantum mechanics

KEY: quantum numbers | magnetic quantum number MSC: general chemistry

1. Which of the following sets of quantum numbers (n, l, m_l, m_s) is not permissible?

A)	3 3 –3 +
B)	2 1 –1 +
C)	1 0 0 +
D)	3 2 –2 –
E)	4 0 0 –

ANS: A PTS: 1 DIF: easy REF: 7.5

OBJ: Apply the rules for quantum numbers. (Example 7.6)

TOP: atomic theory | quantum mechanics KEY: quantum numbers

MSC: general chemistry

1. Which of the following combinations of quantum numbers is permissible?

A)	n = 1, l = 2, ml = 0, ms =
B)	n = 3, l = 2, ml = 1, ms =
C)	n = 3, l = 3, ml = 1, ms =
D)	n = 2, l = 1, ml = –1, ms = 0
E)	n = 4, l = 3, ml = 4, ms =

ANS: B PTS: 1 DIF: easy REF: 7.5

OBJ: Apply the rules for quantum numbers. (Example 7.6)

TOP: atomic theory | quantum mechanics KEY: quantum numbers

MSC: general chemistry

1. Which of the following statements is incorrect?

A)	The set of quantum numbers n = 3, l = 2, ml = 0, ms = is not permitted because ml = 0.
B)	The set of quantum numbers n = 2, l = 2, ml = 1, ms = is not permitted because n = l.
C)	The set of quantum numbers n = 3, l = 2, ml = 1, ms = is permitted.
D)	The set of quantum numbers n = 3, l = 2, ml = 3, ms = is not permitted because ml exceeds l.
E)	The set of quantum numbers n = 4, l = 3, ml = –1, ms = 0 is not permitted because ms = 0.

ANS: A PTS: 1 DIF: moderate REF: 7.5

OBJ: Apply the rules for quantum numbers. (Example 7.6)

TOP: atomic theory | quantum mechanics KEY: quantum numbers

MSC: general chemistry

1. Which of the following statements is incorrect?

A)	The n = 3 shell has three p orbitals.
B)	Every p subshell has three orbital.
C)	The n = 4 shell has seven f orbitals.
D)	An s orbital has a spherical shape.
E)	The n = 2 shell has five d orbitals.

ANS: E PTS: 1 DIF: easy REF: 7.5

OBJ: Apply the rules for quantum numbers. (Example 7.6)

TOP: atomic theory | quantum mechanics KEY: quantum numbers

MSC: general chemistry

1. How many p orbitals are in the n = 4 shell?

A)	1
B)	8
C)	7
D)	5
E)	3

ANS: E PTS: 1 DIF: easy REF: 7.5

OBJ: Apply the rules for quantum numbers. (Example 7.6)

TOP: atomic theory | quantum mechanics KEY: quantum numbers

MSC: general chemistry

1. How many orbitals have the set of quantum numbers ?

A)	5
B)	9
C)	7
D)	1
E)	3

ANS: A PTS: 1 DIF: easy REF: 7.5

OBJ: Apply the rules for quantum numbers. (Example 7.6)

TOP: atomic theory | quantum mechanics KEY: quantum numbers

MSC: general chemistry

1. Which orbital or orbitals is/are specified by the set of quantum numbers n= 4 and l= 3?

A)	4f
B)	3d
C)	1s
D)	2p
E)	4s

ANS: A PTS: 1 DIF: easy REF: 7.5

OBJ: Apply the rules for quantum numbers. (Example 7.6)

TOP: atomic theory | quantum mechanics

1. What is the total number of orbitals found in the n = 4 shell?

A)	16
B)	4
C)	20
D)	24
E)	15

ANS: A PTS: 1 DIF: moderate REF: 7.5

OBJ: Apply the rules for quantum numbers. (Example 7.6)

TOP: atomic theory | quantum mechanics

1. Which of the following is a representation of a 3d_xz orbital?

A)
B)
C)
D)
E)

ANS: A PTS: 1 DIF: easy REF: 7.5

OBJ: Describe the shapes of s, p, and d orbitals.

TOP: atomic theory | quantum mechanics

1. Which of the following is a representation of a orbital?

A)
B)
C)
D)
E)

ANS: A PTS: 1 DIF: easy REF: 7.5

OBJ: Describe the shapes of s, p, and d orbitals.

TOP: atomic theory | quantum mechanics

1. Which hydrogen atom orbital has an energy essentially identical to a 3d orbital?

A)	5d
B)	4p
C)	1s
D)	2s
E)	3p

ANS: E PTS: 1 DIF: moderate REF: 7.5

OBJ: Apply the rules for quantum numbers. (Example 7.6)

TOP: atomic theory | quantum mechanics