Question 1

Calculate the work,w,gained or lost by the system when a gas expands from 15 L to 50 L against a constant external pressure of 1.5 atm.101.3 L ∙ atm = 101 J

Accepted Answer

A)  -7.6 kJ 
B)  -5.3 kJ 
C)  +5.3 kJ 
D)  +7.6 kJ 
A)  -7.6 kJ 
B)  -5.3 kJ 
C)  +5.3 kJ 
D)  +7.6 kJ

Question 2

Give the equation with the elements in MgSO4 in their standard state as the reactants and MgSO4 as the product.

Accepted Answer

Mg(s)+ 1/8

Question 3

Using the following equation for the combustion of octane,calculate the heat associated with the formation of 100.0 g of carbon dioxide.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

Accepted Answer

A)  12520 kJ 
B)  1564 kJ 
C)  1001 kJ 
D)  1391 kJ 
E)  11018 kJ 
A)  12520 kJ 
B)  1564 kJ 
C)  1001 kJ 
D)  1391 kJ 
E)  11018 kJ

Question 4

8.000 moles of H2(g)react with 4.000 mol of O2(g)to form 8.000 mol of H2O(l)at 25°C and a constant pressure of 1.00 atm.If 546.4 kJ of heat are released during this reaction,and PΔV is equal to -29.60 kJ,then

Accepted Answer

A)  ΔH° = +546.4 kJ and ΔE° = +576.06 kJ. 
B)  ΔH° = +546.4 kJ and ΔE° = +516.8 kJ. 
C)  ΔH° = -546.4 kJ and ΔE° = -516.8 kJ. 
D)  ΔH° = -546.4 kJ and ΔE° = -576.0 kJ. 
A)  ΔH° = +546.4 kJ and ΔE° = +576.06 kJ. 
B)  ΔH° = +546.4 kJ and ΔE° = +516.8 kJ. 
C)  ΔH° = -546.4 kJ and ΔE° = -516.8 kJ. 
D)  ΔH° = -546.4 kJ and ΔE° = -576.0 kJ.

Question 5

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

Accepted Answer

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

Question 6

Identify what a coffee cup calorimeter measures.

Accepted Answer

A)  measures ΔH for aqueous solutions 
B)  measures ΔE for combustion reactions 
C)  measures ΔH for hydrolysis solutions 
D)  measures ΔT for combustion solutions 
E)  measures ΔE for reduction reactions 
A)  measures ΔH for aqueous solutions 
B)  measures ΔE for combustion reactions 
C)  measures ΔH for hydrolysis solutions 
D)  measures ΔT for combustion solutions 
E)  measures ΔE for reduction reactions

Question 7

Define heat.

Accepted Answer

A)  the flow of energy caused by a chemical reaction 
B)  the flow of energy caused by a temperature difference 
C)  the result of a force acting through a distance 
D)  the capacity to do work 
E)  a chemical reaction 
A)  the flow of energy caused by a chemical reaction 
B)  the flow of energy caused by a temperature difference 
C)  the result of a force acting through a distance 
D)  the capacity to do work 
E)  a chemical reaction

Question 8

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

Accepted Answer

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

Question 9

An exothermic reaction has

Accepted Answer

A)  a negative ΔH, absorbs heat from the surroundings, and feels cold to the touch. 
B)  a positive ΔH, gives off heat to the surroundings, and feels warm to the touch. 
C)  a negative ΔH, gives off heat to the surroundings, and feels warm to the touch. 
D)  a positive ΔH, absorbs heat from the surroundings, and feels cold to the touch. 
E)  a positive ΔH, absorbs heat from the surroundings, and feels warm to the touch. 
A)  a negative ΔH, absorbs heat from the surroundings, and feels cold to the touch. 
B)  a positive ΔH, gives off heat to the surroundings, and feels warm to the touch. 
C)  a negative ΔH, gives off heat to the surroundings, and feels warm to the touch. 
D)  a positive ΔH, absorbs heat from the surroundings, and feels cold to the touch. 
E)  a positive ΔH, absorbs heat from the surroundings, and feels warm to the touch.

Question 10

Using the following thermochemical equation,determine the amount of heat produced from the combustion of 48.6 g benzene (C6H6).The molar mass of benzene is 78.11 g/mole. 2 C6H6(l)+ 15 O2(g)→ 12 CO2(g)+ 6 H2O(g)ΔH°rxn = -6278 kJ

Accepted Answer

A)  7820 kJ 
B)  3900 kJ 
C)  1950 kJ 
D)  80.2 kJ 
E)  0.604 kJ 
A)  7820 kJ 
B)  3900 kJ 
C)  1950 kJ 
D)  80.2 kJ 
E)  0.604 kJ

Question 11

For a process at constant pressure,12,400 calories of heat are released.This quantity of heat is equivalent to

Accepted Answer

A)  1.92 × 10-5 J. 
B)  5.92 × 103 J. 
C)  6.21 × 104 J. 
D)  5.19 × 104 J. 
E)  8.85 × 105 J. 
A)  1.92 × 10-5 J. 
B)  5.92 × 103 J. 
C)  6.21 × 104 J. 
D)  5.19 × 104 J. 
E)  8.85 × 105 J.

Question 12

Energy that is associated with the temperature of an object is called

Accepted Answer

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

Question 13

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

Accepted Answer

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

Question 14

Calculate the change in internal energy (ΔE)for a system that is giving off 25.0 kJ of heat and is changing from 24.00 L to 21.00 L in volume at 1.50 atm pressure.(Remember that 101.3 J = 1 L∙atm)

Accepted Answer

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

Question 15

At constant pressure,the combustion of 20.0 g of C2H6(g)releases 1036 kJ of heat.What is ΔH for the reaction given below? 2 C2H6(g)+ 7 O2(g)→ 4 CO2(g)+ 6 H2O(l)

Accepted Answer

A)  -86.1 kJ 
B)  -781 kJ 
C)  -1600 kJ 
D)  -3120 kJ 
A)  -86.1 kJ 
B)  -781 kJ 
C)  -1600 kJ 
D)  -3120 kJ

Question 16

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.

Accepted Answer

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 
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 17

Which of the following is NOT a major contributor to energy consumption?

Accepted Answer

A)  residential 
B)  commercial 
C)  transportation 
D)  industrial 
E)  atmospheric 
A)  residential 
B)  commercial 
C)  transportation 
D)  industrial 
E)  atmospheric

Question 18

Choose the reaction that illustrates ΔH°f for Ba(NO3)2.

Accepted Answer

A)  Ba(s) + N2(g) + 3 O2(g) → Ba(NO3)2(s) 
B)  Ba2+(aq) + 2 NO3-(aq) → Ba(NO3)2(aq) 
C)  Ba(s) + 2 N(g) + 6 O(g) → Ba(NO3)2(s) 
D)  Ba(NO3)2(aq) → Ba2+(aq) + 2 NO3-(aq) 
E)  Ba(NO3)2(s) → Ba(s) + N2(g) + 3 O2(g) 
A)  Ba(s) + N2(g) + 3 O2(g) → Ba(NO3)2(s) 
B)  Ba2+(aq) + 2 NO3-(aq) → Ba(NO3)2(aq) 
C)  Ba(s) + 2 N(g) + 6 O(g) → Ba(NO3)2(s) 
D)  Ba(NO3)2(aq) → Ba2+(aq) + 2 NO3-(aq) 
E)  Ba(NO3)2(s) → Ba(s) + N2(g) + 3 O2(g)

Question 19

According to the following reaction,how much energy is evolved during the reaction of 2.50 L B2H6 and 5.65 L 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

Accepted Answer

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

Question 20

A sample of copper absorbs 43.6 kJ of heat,resulting in a temperature rise of 50.0°C,determine the mass (in kg)of the copper sample if the specific heat capacity of copper is 0.385 J/g°C.

Accepted Answer

A)  2.26 kg 
B)  0.235 kg 
C)  6.64 kg 
D)  11.9 kg 
E)  5.10 kg 
A)  2.26 kg 
B)  0.235 kg 
C)  6.64 kg 
D)  11.9 kg 
E)  5.10 kg

Exam 6: Thermochemistry

Calculate the work,w,gained or lost by the system when a gas expands from 15 L to 50 L against a constant external pressure of 1.5 atm.101.3 L ∙ atm = 101 J

Give the equation with the elements in MgSO4 in their standard state as the reactants and MgSO4 as the product.

Using the following equation for the combustion of octane,calculate the heat associated with the formation of 100.0 g of carbon dioxide.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

8.000 moles of H2(g)react with 4.000 mol of O2(g)to form 8.000 mol of H2O(l)at 25°C and a constant pressure of 1.00 atm.If 546.4 kJ of heat are released during this reaction,and PΔV is equal to -29.60 kJ,then

Identify what a coffee cup calorimeter measures.

Define heat.

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

An exothermic reaction has

Using the following thermochemical equation,determine the amount of heat produced from the combustion of 48.6 g benzene (C6H6).The molar mass of benzene is 78.11 g/mole. 2 C6H6(l)+ 15 O2(g)→ 12 CO2(g)+ 6 H2O(g)ΔH°rxn = -6278 kJ

For a process at constant pressure,12,400 calories of heat are released.This quantity of heat is equivalent to

Energy that is associated with the temperature of an object is called

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

Calculate the change in internal energy (ΔE)for a system that is giving off 25.0 kJ of heat and is changing from 24.00 L to 21.00 L in volume at 1.50 atm pressure.(Remember that 101.3 J = 1 L∙atm)

At constant pressure,the combustion of 20.0 g of C2H6(g)releases 1036 kJ of heat.What is ΔH for the reaction given below? 2 C2H6(g)+ 7 O2(g)→ 4 CO2(g)+ 6 H2O(l)

Which of the following is NOT a major contributor to energy consumption?

Choose the reaction that illustrates ΔH°f for Ba(NO3)2.

According to the following reaction,how much energy is evolved during the reaction of 2.50 L B2H6 and 5.65 L 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 sample of copper absorbs 43.6 kJ of heat,resulting in a temperature rise of 50.0°C,determine the mass (in kg)of the copper sample if the specific heat capacity of copper is 0.385 J/g°C.

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Give the equation with the elements in MgSO₄ in their standard state as the reactants and MgSO₄ as the product.

Using the following equation for the combustion of octane,calculate the heat associated with the formation of 100.0 g of carbon dioxide.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

8.000 moles of H₂(g)react with 4.000 mol of O₂(g)to form 8.000 mol of H₂O(l)at 25°C and a constant pressure of 1.00 atm.If 546.4 kJ of heat are released during this reaction,and PΔV is equal to -29.60 kJ,then

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

Using the following thermochemical equation,determine the amount of heat produced from the combustion of 48.6 g benzene (C₆H₆).The molar mass of benzene is 78.11 g/mole. 2 C₆H₆(l)+ 15 O₂(g)→ 12 CO₂(g)+ 6 H₂O(g)ΔH°_rxn= -6278 kJ

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

Calculate the change in internal energy (ΔE)for a system that is giving off 25.0 kJ of heat and is changing from 24.00 L to 21.00 L in volume at 1.50 atm pressure.(Remember that 101.3 J = 1 L^∙atm)

At constant pressure,the combustion of 20.0 g of C₂H₆(g)releases 1036 kJ of heat.What is ΔH for the reaction given below? 2 C₂H₆(g)+ 7 O₂(g)→ 4 CO₂(g)+ 6 H₂O(l)

Choose the reaction that illustrates ΔH°_f for Ba(NO₃)₂.

According to the following reaction,how much energy is evolved during the reaction of 2.50 L B₂H₆ and 5.65 L Cl₂?(Both gases are initially at STP.)The molar mass of B₂H₆is 27.67 g/mol. B₂H₆(g)+ 6 Cl₂(g)→ 2 BCl₃(g)+ 6 HCl(g)ΔH°_rxn= -1396 kJ