Deck 10: Thermochemistry

Question 1

Define potential energy.

A) energy associated with the temperature of an object
B) energy associated with the motion of an object
C) energy associated with the force of an object
D) energy associated with the gravity of an object
E) energy associated with the position or composition of an object

Answer 1

energy associated with the position or composition of an object

Question 2

The temperature rises from 25.00°C to 29.00°C in a bomb calorimeter when 3.50 g of sucrose undergoes combustion in a bomb calorimeter.Calculate ΔE_rxn for the combustion of sucrose in kJ/mol sucrose.The heat capacity of the calorimeter is 4.90 kJ/°C.The molar mass of sugar is 342.3 g/mol.

A) (^- 1.92) × 10³ kJ/mole
B) 1.92 × 10³ kJ/mole
C) (^- 1.23) × 10³ kJ/mole
D) 2.35 × 10⁴ kJ/mole

Answer 2

(^- 1.92) × 10³ kJ/mole

Question 3

The law of ________ states that energy that can be neither created or destroyed.

A) kinetic energy
B) the consecration of energy
C) potential energy
D) the conservation of energy
E) thermochemistry

Answer 3

the conservation of energy

Question 4

A sample of copper absorbs 43.6 kJ of heat,resulting in a temperature rise of 75.0°C,determine the mass (in kg)of the copper sample if the specific heat capacity of copper is 0.385 J/g°C.

A) 1.51 kg
B) 6.62 kg
C) 1.26 kg
D) 7.94 kg
E) 3.64 kg

Question 5

Define kinetic energy.

A) energy associated with the temperature of an object
B) energy associated with the motion of an object
C) energy associated with the force of an object
D) energy associated with the gravity of an object
E) energy associated with the position or composition of an object

Question 6

A 4.98 g sample of aniline (C₆H₅NH₂,molar mass = 93.13 g/mol)was combusted in a bomb calorimeter with a heat capacity of 4.25 kJ/°C.If the temperature rose from 29.5°C to 69.8°C,determine the value of ΔH°_comb for aniline.

A) +7.81 × 10³ kJ/mol
B) -3.20 × 10³ kJ/mol
C) +1.71 × 10³ kJ/mol
D) -1.71 × 10³ kJ/mol
E) -7.81 × 10³ kJ/mol

Question 7

Calculate the change in internal energy (ΔE)for a system that is giving off 25.0 kJ of heat and is changing from 18.00 L to 15.00 L in volume at 1.50 atm pressure.(Remember that 101.3 J = 1 L^∙atm)

A) +25.5 kJ
B) -16.0 kJ
C) -25.5 kJ
D) -24.5 kJ
E) 456 kJ

Question 8

Which of the following statements about energy is FALSE?

A) Energy can be converted from one type to another.
B) The total energy of a system remains constant.
C) Kinetic energy is the energy associated with its position or composition.
D) Energy is the capacity to do work.
E) Systems tend to change in order to lower their potential energy.

Question 9

For ?E_sys to always be -,what must be TRUE?

A) q = w
B) +q > -w
C) +w > -q
D) -w > +q

Question 10

A 21.8 g sample of ethanol (C₂H₅OH)is burned in a bomb calorimeter,according to the following reaction.If the temperature rises from 25.0 to 62.3°C,determine the heat capacity of the calorimeter.The molar mass of ethanol is 46.07 g/mol. C₂H₅OH(l)+ 3 O₂(g)→ 2 CO₂(g)+ 3 H₂O(g)ΔH°_rxn = -1235 kJ

A) 4.99 kJ/°C
B) 5.65 kJ/°C
C) 63.7 kJ/°C
D) 33.1 kJ/°C
E) 15.7 kJ/°C

Question 11

A 35.6 g sample of ethanol (C₂H₅OH)is burned in a bomb calorimeter,according to the following reaction.If the temperature rose from 35.0 to 76.0°C and the heat capacity of the calorimeter is 23.3 kJ/°C,what is the value of DH°_rxn? The molar mass of ethanol is 46.07 g/mol.
C₂H₅OH(l)+ 3 O₂(g)→ 2 CO₂(g)+ 3 H₂O(g)ΔH°_rxn = ?

A) -1.24 × 10³ kJ/mol
B) +1.24 × 10³ kJ/mol
C) -8.09 × 10³ kJ/mol
D) -9.55 × 10³ kJ/mol
E) +9.55 × 10³ kJ/mol

Question 12

Define thermal energy.

A) energy associated with the temperature of an object
B) energy associated with the motion of an object
C) energy associated with the force of an object
D) energy associated with the gravity of an object
E) energy associated with the position or composition of an object

Question 13

A 12.8 g sample of ethanol (C₂H₅OH)is burned in a bomb calorimeter with a heat capacity of 5.65 kJ/°C.Using the information below,determine the final temperature of the calorimeter if the initial temperature is 25.0°C.The molar mass of ethanol is 46.07 g/mol. C₂H₅OH(l)+ 3 O₂(g)→ 2 CO₂(g)+ 3 H₂O(g)ΔH°_rxn = -1235 kJ

A) 53.4°C
B) 28.1°C
C) 111°C
D) 85.7°C
E) 74.2°C

Question 14

Determine the final temperature of a gold nugget (mass = 376 g)that starts at 398 K and loses 4.85 kJ of heat to a snowbank when it is lost.The specific heat capacity of gold is 0.128 J/g°C.

A) 133 K
B) 398 K
C) 187 K
D) 297 K
E) 377 K

Question 15

Which of the following signs on q and w represent a system that is doing work on the surroundings,as well as gaining heat from the surroundings?

A) q = +, w = -
B) q = -, w = +
C) q = +, w = +
D) q = -, w = -
E) None of these represent the system referenced above.

Question 16

A 6.55 g sample of aniline (C₆H₅NH₂,molar mass = 93.13 g/mol)was combusted in a bomb calorimeter.If the temperature rose by 32.9°C,use the information below to determine the heat capacity of the calorimeter. 4 C₆H₅NH₂(l)+ 35 O₂(g)→ 24 CO₂(g)+ 14 H₂O(g)+ 4 NO₂(g)
ΔH°_rxn = -1.28 × 10⁴ kJ

A) 97.3 kJ/°C
B) 38.9 kJ/°C
C) 5.94 kJ/°C
D) 6.84 kJ/°C
E) 12.8 kJ/°C

Question 17

Energy that is associated with the relative positions of electrons and nuclei in atoms and molecules is called

A) kinetic energy.
B) thermal energy.
C) gravitational energy.
D) chemical energy.

Question 18

Determine the specific heat capacity of an alloy that requires 59.3 kJ to raise the temperature of 150.0 g alloy from 298 K to 398 K.

A) 4.38 J/g°C
B) 2.29 J/g°C
C) 3.95 J/g°C
D) 2.53 J/g°C
E) 1.87 J/g°C

Question 19

Calculate the change in internal energy (ΔE)for a system that is giving off 25.0 kJ of heat and is changing from 12.00 L to 6.00 L in volume at 1.50 atm pressure.(Remember that 101.3 J = 1 L^∙atm)

A) +25.9 kJ
B) -16.0 kJ
C) -25.9 kJ
D) -24.1 kJ
E) 937 kJ

Question 20

Which of the following (with specific heat capacity provided)would show the smallest temperature change upon gaining 200.0 J of heat?

A) 50.0 g Al, C_Al = 0.903 J/g°C
B) 50.0 g Cu, C_Cu = 0.385 J/g°C
C) 25.0 g granite, C_granite = 0.79 J/g°C
D) 25.0 g Au, C_Au = 0.128 J/g°C
E) 25.0 g Ag, C_Ag = 0.235 J/g°C

Question 21

According to the following reaction,how much energy is evolved during the reaction of 0.111 mol B₂H₆ and 0.252 mol Cl₂ (Both gases are initially at STP)? The molar mass of B₂H₆ is 27.67 g/mol.
B₂H₆(g)+ 6 Cl₂(g)→ 2 BCl₃(g)+ 6 HCl(g)ΔH°_rxn = -1396 kJ

A) 58.7 kJ
B) 156 kJ
C) 215 kJ
D) 352 kJ
E) 508 kJ

Question 22

A student is preparing to perform a series of calorimetry experiments.She first wishes to determine the calorimeter constant (C_cal)for her coffee cup calorimeter.She pours a 50.0 mL sample of water at 345 K into the calorimeter containing a 50.0 mL sample of water at 298 K.She carefully records the final temperature of the water as 317 K.What is the value of C_cal for the calorimeter?

A) 19 J/K
B) 28 J/K
C) 99 J/K
D) 21 J/K
E) 76 J/K

Question 23

Which of the following statements is TRUE?

A) State functions do not depend on the path taken to arrive at a particular state.
B) DE_rxn can be determined using constant volume calorimetry.
C) Energy is neither created nor destroyed, excluding nuclear reactions.
D) ΔH_rxn can be determined using constant pressure calorimetry.
E) All of the above are true.

Question 24

According to the following reaction,how much energy is evolved during the reaction of 32.5 g B₂H₆ and 72.5 g Cl₂? The molar mass of B₂H₆ is 27.67 g/mol.
B₂H₆(g)+ 6 Cl₂(g)→ 2 BCl₃(g)+ 6 HCl(g)ΔH°_rxn = -1396 kJ

A) 1640 kJ
B) 238 kJ
C) 1430 kJ
D) 3070 kJ
E) 429 kJ

Question 25

How much energy is evolved during the formation of 197 g of Fe,according to the reaction below?
Fe₂O₃(s)+ 2 Al(s)→ Al₂O₃(s)+ 2 Fe(s)ΔH°_rxn = -852 kJ

A) 1.52 × 10³ kJ
B) 3.02 × 10³ kJ
C) 8.40 × 10³ kJ
D) 964 kJ
E) 482 kJ

Question 26

A 6.55 g sample of aniline (C₆H₅NH₂,molar mass = 93.13 g/mol)was combusted in a bomb calorimeter with a heat capacity of 14.25 kJ/°C.If the initial temperature was 32.9°C,use the information below to determine the value of the final temperature of the calorimeter. 4 C₆H₅NH₂(l)+ 35 O₂(g)→ 24 CO₂(g)+ 14 H₂O(g)+ 4 NO₂(g)
ΔH°_rxn = -1.28 × 10⁴ kJ

A) 257°C
B) 46.6°C
C) 48.7°C
D) 41.9°C
E) 931°C

Question 27

Which statement is FALSE?

A) An exothermic reaction gives heat off heat to the surroundings.
B) Enthalpy is the sum of a system's internal energy and the product of pressure and volume change.
C) ΔE_rxn is a measure of heat.
D) ΔH_rxn is the heat of reaction.
E) Endothermic has a positive ΔH.

Question 28

A piece of iron (mass = 25.0 g)at 398 K is placed in a styrofoam coffee cup containing 25.0 mL of water at 298 K.Assuming that no heat is lost to the cup or the surroundings,what will the final temperature of the water be? The specific heat capacity of iron = 0.449 J/g°C and water = 4.18 J/g°C.

A) 348 K
B) 308 K
C) 287 K
D) 325 K
E) 388 K

Question 29

Using the following equation for the combustion of octane,calculate the amount of moles of oxygen that reacts with 100.0 g of octane.The molar mass of octane is 114.33 g/mole.The molar mass of carbon dioxide is 44.0095 g/mole. 2 C₈H₁₈ + 25 O₂ → 16 CO₂ + 18 H₂O ΔH°_rxn = -11018 kJ

A) 18.18 moles
B) 6.997 moles
C) 14.00 moles
D) 8.000 moles
E) 10.93 moles

Question 30

Given w = 0,an endothermic reaction has the following.

A) +ΔH and -ΔE
B) - ΔH and +ΔE
C) + ΔH and +ΔE
D) - ΔH and -ΔE

Question 31

Using the following equation for the combustion of octane,calculate the amount of grams of carbon dioxide formed from 100.0 g of octane.The molar mass of octane is 114.33 g/mole.The molar mass of carbon dioxide is 44.0095 g/mole. 2 C₈H₁₈ + 25 O₂ → 16 CO₂ + 18 H₂O ΔH°_rxn = -11018 kJ

A) 800.1 g
B) 307.9 g
C) 260.1 g
D) 792.3 g

Question 32

How much energy is required to decompose 765 g of PCl₃,according to the reaction below? The molar mass of PCl₃ is 137.32 g/mol and may be useful.
4 PCl₃(g)→ P₄(s)+ 6 Cl₂(g)ΔH°_rxn = +1207 kJ

A) 2.31 × 10³ kJ
B) 4.33 × 103 kJ
C) 6.72 × 10³ kJ
D) 1.68 × 10³ kJ
E) 5.95 × 10³ kJ

Question 33

Using the following thermochemical equation,determine the amount of heat produced per kg of CO₂ formed during the combustion of benzene (C₆H₆). 2 C₆H₆(l)+ 15 O₂(g)→ 12 CO₂(g)+ 6 H₂O(g)ΔH°_rxn = -6278 kJ

A) 1.43 × 10⁵ kJ/kg CO₂
B) 2.30 × 10⁴ kJ/kg CO₂
C) 4.34 × 10⁴ kJ/kg CO₂
D) 1.19 × 10⁴ kJ/kg CO₂
E) 8.40 × 10⁵ kJ/kg CO₂

Question 34

A 100.0 mL sample of 0.300 M NaOH is mixed with a 100.0 mL sample of 0.300 M HNO₃ in a coffee cup calorimeter.If both solutions were initially at 35.00°C and the temperature of the resulting solution was recorded as 37.00°C,determine the ΔH°_rxn (in units of kJ/mol NaOH)for the neutralization reaction between aqueous NaOH and HCl.Assume 1)that no heat is lost to the calorimeter or the surroundings,and 2)that the density and the heat capacity of the resulting solution are the same as water.

A) -55.7 kJ/mol NaOH
B) -169 kJ/mol NaOH
C) -16.7 kJ/mol NaOH
D) -27.9 kJ/mol NaOH
E) - 34.4 kJ/mol NaOH

Question 35

Using the following equation for the combustion of octane,calculate the amount of moles of carbon dioxide formed from 100.0 g of octane.The molar mass of octane is 114.33 g/mole.The molar mass of carbon dioxide is 44.0095 g/mole. 2 C₈H₁₈ + 25 O₂ → 16 CO₂ + 18 H₂O ΔH°_rxn = -11018 kJ

A) 18.18 moles
B) 6.997 moles
C) 14.00 moles
D) 8.000 moles
E) 10.93 moles

Question 36

How much energy is required to decompose 612 g of PCl₃,according to the reaction below? The molar mass of PCl₃ is 137.32 g/mol and may be useful.
4 PCl₃(g)→ P₄(s)+ 6 Cl₂(g)ΔH°_rxn = +1207 kJ

A) 1.85 × 10³ kJ
B) 3.46 × 103 kJ
C) 5.38 × 10³ kJ
D) 1.34 × 10³ kJ
E) 4.76 × 10³ kJ

Question 37

How much energy is evolved during the formation of 98.7 g of Fe,according to the reaction below?
Fe₂O₃(s)+ 2 Al(s)→ Al₂O₃(s)+ 2 Fe(s)ΔH°_rxn = -852 kJ

A) 753 kJ
B) 1.51 × 10³ kJ
C) 4.20 × 10³ kJ
D) 482 kJ
E) 241 kJ

Question 38

Two aqueous solutions are both at room temperature and are then mixed in a coffee cup calorimeter.The reaction causes the temperature of the resulting solution to fall below room temperature.Which of the following statements is TRUE?

A) The products have a lower potential energy than the reactants.
B) This type of experiment will provide data to calculate ΔE_rxn.
C) The reaction is exothermic.
D) Energy is leaving the system during reaction.
E) None of the above statements are true.

Question 39

According to the following thermochemical equation,what mass of HF (in g)must react in order to produce 345 kJ of energy? Assume excess SiO₂.
SiO₂(s)+ 4 HF(g)→ SiF₄(g)+ 2 H₂O(l)ΔH°_rxn = -184 kJ

A) 42.7 g
B) 37.5 g
C) 150. g
D) 107 g
E) 173 g

Question 40

What volume of benzene (C₆H₆,d= 0.88 g/mL,molar mass = 78.11 g/mol)is required to produce 1.5 × 10³ kJ of heat according to the following reaction?
2 C₆H₆(l)+ 15 O₂(g)→ 12 CO₂(g)+ 6 H₂O(g)ΔH°_rxn = -6278 kJ

A) 75 mL
B) 37 mL
C) 21 mL
D) 19 mL
E) 42 mL

Question 41

Which of the following processes are endothermic?

A) the reaction associated with the lattice energy of LiCl
B) the reaction associated with the ionization energy of potassium
C) the reaction associated with the heat of formation of CaS
D) the formation of F₂ from its elements in their standard states
E) None of the above are endothermic.

Question 42

Use the standard reaction enthalpies given below to determine ΔH°_rxn for the following reaction 2 NO(g)+ O₂(g)→ 2 NO₂(g)ΔH°_rxn = ?
Given:
N₂(g)+ O₂(g)→ 2 NO(g)ΔH°_rxn = +183 kJ
1/2 N₂(g)+ O₂(g)→ NO₂(g)ΔH°_rxn = +33 kJ

A) -150. kJ
B) -117 kJ
C) -333 kJ
D) +115 kJ
E) +238 kJ

Question 43

Use the bond energies provided to estimate ΔH°_rxn for the reaction below. XeF_{2 +} 2 F₂ → XeF₆ ΔH°_rxn = ?
Bond Bond Energy (kJ/mol)
Xe-F 147
F-F 159

A) -429 kJ
B) +159 kJ
C) -660 kJ
D) +176 kJ
E) -270 kJ

Question 44

Use the bond energies provided to estimate ΔH°_rxn for the reaction below. 2 Br₂(l)+ C₂H₂(g)→ C₂H₂Br₄(l)ΔH°_rxn = ?
Bond Bond Energy (kJ/mol)
Br-Br 193
C≡C 837
C-C 347
C-Br 276
C-H 414

A) +407 kJ
B) -324 kJ
C) -228 kJ
D) +573 kJ
E) -648 kJ

Question 45

Which of the following processes are endothermic?

A) K⁺(g) + I⁻(g) → KI(s)
B) 2 Br(g) → Br₂(g)
C) Ca(s) → Ca(g)
D) 2 Na(s) + O₂(g) → Na₂O(s)
E) None of the above are endothermic.

Question 46

Two solutions,initially at 24.69°C,are mixed in a coffee cup calorimeter (C_cal = 105.5 J/°C).When a 200.0 mL volume of 0.100 M AgNO₃ solution is mixed with a 100.0 mL sample of 0.100 M NaCl solution,the temperature in the calorimeter rises to 25.16°C.Determine the DH°_rxn,in units of kJ/mol AgCl.Assume that the density and heat capacity of the solutions is the same as that of water.Hint: Write a balanced reaction for the process.

A) -32 kJ/mol AgCl
B) -78 kJ/mol AgCl
C) -64 kJ/mol AgCl
D) -25 kJ/mol AgCl
E) -59 kJ/mol AgCl

Question 47

Use the bond energies provided to estimate ΔH°_rxn for the reaction below. C₂H₄(g)+ H₂(g)→ C₂H₆(g)ΔH°_rxn = ?
Bond Bond Energy (kJ/mol)
C-C 347
C-H 414
C=C 611
C≡C 837
H-H 436

A) -128 kJ
B) +98 kJ
C) +700 kJ
D) -102 kJ
E) -166 kJ

Question 48

Use the standard reaction enthalpies given below to determine ΔH°_rxn for the following reaction 2 S(s)+ 3 O₂(g)→ 2 SO₃(g)ΔH°_rxn = ?
Given:
SO₂(g)→ S(s)+ O₂(g)ΔH°_rxn = +296.8 kJ
2 SO₂(g)+ O₂(g)→ 2 SO₃(g)ΔH°_rxn = -197.8 kJ

A) -494.6 kJ
B) -692.4 kJ
C) -791.4 kJ
D) 1583 kJ
E) -293.0 kJ

Question 49

Which of the following processes are exothermic?

A) the second ionization energy of Mg
B) the sublimation of Li
C) the breaking the bond of I₂
D) the formation of NaBr from its constituent elements in their standard state
E) None of the above are exothermic.

Question 50

Which of the following processes are exothermic?

A) Cl₂(g) → 2Cl(g)
B) Br(g) + e⁻ → Br⁻(g)
C) Li(s) → Li(g)
D) NaF(s) → Na⁺(g) + F⁻(g)
E) None of the above are exothermic.

Question 51

Use the ΔH°_f information provided to calculate ΔH°_rxn for the following ΔH°_{f (kJ/mol)} SO₂Cl₂(g)+ 2 H₂O(l)→ 2 HCl(g)+ H₂SO4(l)ΔH°_rxn = ?
SO₂Cl₂(g)-364
H₂O(l)-286
HCl(g)-92
H₂SO₄(l)-814

A) -256 kJ
B) +161 kJ
C) -62 kJ
D) +800. kJ
E) -422 kJ

Question 52

Use the ΔH°_f and ΔH°_rxn information provided to calculate ΔH°_f for IF ΔH°_{f (kJ/mol)} IF₇(g)+ I₂(g)→ IF₅(g)+ 2 IF(g)ΔH°_rxn = -89 kJ
IF₇(g)941
IF₅(g)840

A) 101 kJ/mol
B) -146 kJ/mol
C) -190. kJ/mol
D) -95 kJ/mol
E) 24 kJ/mol

Question 53

Use the bond energies provided to estimate ΔH°_rxn for the reaction below. CH₃OH(l)+ 2 O₂(g)→ CO₂(g)+ 2 H₂O(g)ΔH°_rxn = ?
Bond Bond Energy (kJ/mol)
C-H 414
C-O 360
C=O 799
O=O 498
O-H 464

A) +473 kJ
B) -91 kJ
C) -486 kJ
D) -392 kJ
E) +206 kJ

Question 54

Use the standard reaction enthalpies given below to determine ΔH°_rxn for the following reaction P₄(g)+ 10 Cl₂(g)→ 4PCl₅(s)ΔH°_rxn = ?
Given:
PCl₅(s)→ PCl₃(g)+ Cl₂(g)ΔH°_rxn = +157 kJ
P₄(g)+ 6 Cl₂(g)→ 4 PCl₃(g)ΔH°_rxn = -1207 kJ

A) -1835 kJ
B) -1364 kJ
C) -1050. kJ
D) -1786 kJ
E) -2100. kJ

Question 55

Which of the following is NOT a standard state?

A) For a solid, it is 25°F.
B) For a liquid, it is 25°C.
C) For a gas, it is 1 atm.
D) For a solution, it is 1 M.
E) For a liquid, it is 1 atm.

Question 56

Choose the thermochemical equation that illustrates ΔH°_f for Li₂SO₄.

A) 2 Li⁺(aq) + SO₄^2-(aq) → Li₂SO₄(aq)
B) 2 Li(s) + 1/8 S₈(s, rhombic) + 2 O₂(g) → Li₂SO₄(s)
C) Li₂SO₄(aq) → 2 Li⁺(aq) + SO₄^2-(aq)
D) 8 Li₂SO₄(s) → 16 Li(s) + S₈(s, rhombic) + 16 O₂(g)
E) 16 Li(s) + S₈(s, rhombic) + 16 O₂(g) → 8 Li₂SO₄(s)

Question 57

Use the bond energies provided to estimate ΔH°_rxn for the reaction below. PCl₃(g)+ Cl₂(g)→ PCl₅(l)ΔH°_rxn = ?
Bond Bond Energy (kJ/mol)
Cl-Cl 243
P-Cl 331

A) -243 kJ
B) -419 kJ
C) -662 kJ
D) -67 kJ
E) -905 kJ

Question 58

Use the standard reaction enthalpies given below to determine ΔH°_rxn for the following reaction 4 SO₃(g)→ 4 S(s)+ 6 O₂(g)ΔH°_rxn = ?
Given:
SO₂(g)→ S(s)+ O₂(g)ΔH°_rxn = +296.8 kJ
2 SO₂(g)+ O₂(g)→ 2 SO₃(g)ΔH°_rxn = -197.8 kJ

A) -494.6 kJ
B) -692.4 kJ
C) -791.4 kJ
D) 1583 kJ
E) -293.0 kJ

Question 59

Which of the following is NOT a standard state?

A) For a liquid, it is 25°F.
B) For a solid, it is 25°C.
C) For a solid, it is 1 atm.
D) For a solution, it is 1 M.
E) For a liquid, it is 1 atm.

Question 60

Two solutions,initially at 24.60°C,are mixed in a coffee cup calorimeter (C_cal = 15.5 J/°C).When a 100.0 mL volume of 0.100 M AgNO₃ solution is mixed with a 100.0 mL sample of 0.200 M NaCl solution,the temperature in the calorimeter rises to 25.30°C.Determine the DH°_rxn for the reaction as written below.Assume that the density and heat capacity of the solutions is the same as that of water. NaCl(aq)+ AgNO₃(aq)→ AgCl(s)+ NaNO₃(aq)DH°_rxn = ?

A) -35 kJ
B) -69 kJ
C) -250 kJ
D) -16 kJ
E) -140 kJ

Question 61

Define heat capacity.

A) the quantity of heat required to lower the temperature of 1 mole of a substance by 1°C
B) the quantity of heat required to change a system's temperature by 1°C
C) the quantity of heat required to lower the temperature of 1 gram of a substance by 1°C
D) the quantity of heat required to raise the temperature of 1 g of a substance by 1°F
E) the quantity of heat required to lower the temperature of 1 liter of a substance by 1°C

Question 62

Use the information provided to determine ΔH°_rxn for the following reaction ΔH°_f (kJ/mol)CH₄(g)+ 3 Cl₂(g)→ CHCl₃(l)+ 3 HCl(g)ΔH°_rxn = ?
CH₄(g)-75
CHCl₃(l)-134
HCl(g)-92

A) -151 kJ
B) -335 kJ
C) +662 kJ
D) +117 kJ
E) -217 kJ

Question 63

Which compound should have the largest lattice energy?

A) SrI₂
B) CaCl₂
C) NaI
D) MgO
E) KF

Question 64

Calculate the kinetic energy of a 150 g baseball moving at a speed of 39.m/s ( 87 mph).

A) 5.8 J
B) 1.1 × 10² J
C) 5.8 × 10³ J
D) 1.1 × 10⁵ J

Question 65

A sample of NI3 is contained in a piston and cylinder.The samples rapidly decomposes to form nitrogen gas and iodine gas,and releases 3.30 kJ of heat and does 950 J of work.What is ∆E?

A) -953.3 J
B) +953.3 J
C) -4250 J
D) -946.7 J
E) +4250 J

Question 66

Which one of the following statements is NOT true concerning the equation below?
N₂(g)+ 3 H₂(g)→ 2 NH₃(g)ΔH°_rxn = -459.0 kJ

A) The production of 1.00 mole of ammonia is accompanied by the production of 229.5 kJ of heat.
B) The complete reaction of 1.00 moles of nitrogen requires 459 kJ of heat.
C) The complete reaction of 1.00 moles of hydrogen produces 153 kJ of heat.
D) The complete reaction of 0.8278 moles of hydrogen requires 0.2759 moles of nitrogen.
E) The reaction is exothermic.

Question 67

Use the information provided to determine ΔH°_rxn for the following reaction ΔH°_f (kJ/mol)3 Fe₂O₃(s)+ CO(g)→ 2 Fe₃O₄(s)+ CO₂(g)ΔH°_rxn = ?
Fe₂O₃(s)-824
Fe₃O₄(s)-1118
CO(g)-111
CO₂(g)-394

A) +277 kJ
B) -577 kJ
C) -47 kJ
D) +144 kJ
E) -111 kJ

Question 68

Which one of the following elements is NOT in its standard state?

A) Br₂(g)
B) F₂(g)
C) Hg(l)
D) Na(s)
E) Cl₂(g)

Question 69

Use the information provided to determine ΔH°_rxn for the following reaction ΔH°_f (kJ/mol)CH₄(g)+ 4 Cl₂(g)→ CCl₄(g)+ 4 HCl(g)ΔH°_rxn = ?
CH₄(g)-75
CCl₄(g)-96
HCl(g)-92

A) -389 kJ
B) -113 kJ
C) +113 kJ
D) -71 kJ
E) +79 kJ

Question 70

Calculate the change internal energy (ΔE)for a system that is giving off 65.0 kJ of heat and is performing 855 J of work on the surroundings.

A) 64.1 kJ
B) -64.1 kJ
C) -65.9 kJ
D) 9.00 × 10² kJ
E) -9.00 × 10² kJ

Question 71

Which of the following is TRUE if ΔE_sys = - 115 J?

A) The system is gaining 115 J, while the surroundings are losing 115 J.
B) The system is losing 115 J, while the surroundings are gaining 115 J.
C) Both the system and the surroundings are gaining 115 J.
D) Both the system and the surroundings are losing 115 J.
E) None of the above are true.

Question 72

For the reaction: NO(g)+ 1/2 O₂(g)→ NO₂(g)
ΔH°_rxn is -114.14 kJ/mol.Calculate ΔH°_f of gaseous nitrogen monoxide,given that ΔH°_f of NO₂(g)is 33.90 kJ/mol.

A) 148.0 kJ/mol
B) 91.04 kJ/mol
C) -114.1 kJ/mol
D) 181.9 kJ/mol
E) -35.64 kJ/mol

Question 73

A 43.9-g piece of copper (C_Cu= 0.385 J/g°C)at 135.0°C is plunged into 254 g of water at 39.0°C.Assuming that no heat is lost to the surroundings,what will the final temperature of the system be?

A) 100.0°C
B) 40.5°C
C) 62.5°C
D) 87.0°C
E) 53.1°C

Question 74

All the following are state functions EXCEPT

A) ∆E.
B) PV.
C) ∆H.
D) q.
E) all of the above are state functions.

Question 75

A piece of metal weighing 57.3 g is heated to a temperature of 88.0°C and is then immersed in 155 g of water at a temperature of 21.53°C.After equilibration the temperature is 24.72°C.If C_H2O = 4.184 J/g°C,what is C_metal?

A) .370 J/g°C
B) .164 J/g°C
C) 1.00 J/g°C
D) 2.11 J/g°C
E) .571 J/g°C

Question 76

Define specific heat capacity.

A) the quantity of heat required to lower the temperature of 1 mole of a substance by 1°C
B) the quantity of heat required to change a system's temperature by 1°C
C) the quantity of heat required to raise the temperature of 1 gram of a substance by 1°C
D) the quantity of heat required to lower the temperature of 1 gram of a substance by 1°F
E) the quantity of heat required to lower the temperature of 1 liter of a substance by 1°C

Question 77

In a bomb calorimeter,reactions are carried out

A) at fixed pressure.
B) at fixed volume.
C) at fixed temperature.
D) with solids only.
E) using water as a solvent.

Question 78

Use the ΔH°_f and ΔH°_rxn information provided to calculate ΔH°_f for SO₃(g) ΔH°_{f (kJ/mol)} 2 SO₂(g)+ O₂(g)→ 2 SO₃(g)ΔH°_rxn = -198 kJ
SO₂(g)-297

A) -792 kJ/mol
B) -248 kJ/mol
C) -495 kJ/mol
D) -578 kJ/mol
E) -396 kJ/mol

Question 79

How much heat energy is required to raise the temperature of 0.298 mole of water from 35.93°C to 79.84°C? The specific heat capacity of water = 4.18 J/g°C.

A) 13.1 J
B) 54.7 J
C) 985 J
D) 2105 J
E) 3310 J

Question 80

For a process at constant pressure,49,600 calories of heat are released.This quantity of heat is equivalent to

A) 4.82 × 10^-6 J.
B) 1.19 × 10⁴ J.
C) 1.24 × 10⁴ J.
D) 2.08 × 10⁵ J.