Question 1

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?

Accepted Answer

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

Question 2

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.

Accepted Answer

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

Question 3

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

Accepted Answer

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

Question 4

A motor does 30 kJ of work and loses 4 kJ as heat to the surroundings.What is the change in the internal energy of the motor?

Accepted Answer

A) -34 kJ 
B) +34 kJ 
C) -26 kJ 
D) +26 kJ

Question 5

An ice cube melts and cools the surrounding beverage.(The ice cube is the system. )Which of the following statement is correct?

Accepted Answer

A) The system loses heat to the surroundings. 
B) The system gains heat from the surroundings. 
C) The system does work on the surroundings. 
D) The surroundings does work on the system.

Question 6

The enthalpy of combustion of gasoline (C8H18)is 5471 kJ mol-1. How much heat will be produced by burning 1 gallon of gasoline at 25°C? (Density of gasoline = 0.703 g/mL;1gallon = 3.78 L)

Accepted Answer

A) 1.3 × 105 kJ 
B) 5451 kJ 
C) 2.0 × 104 kJ 
D) 2.0 × 104 J

Question 7

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

Accepted Answer

A) 2 Li+(aq)+ SO42-(aq)→ Li2SO4(aq) 
B) 2 Li(s)+ 1/8 S8(s,rhombic)+ 2 O2(g)→ Li2SO4(s) 
C) Li2SO4(aq)→ 2 Li+(aq)+ SO42-(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 8

According to the following thermochemical equation,what mass of H2O (in g)must form in order to produce 488 kJ of energy?
SiO2(s)+ 4 HF(g)→ SiF4(g)+ 2 H2O(l)ΔH°rxn = -184 kJ

Accepted Answer

A) 34.0 g 
B) 51 g 
C) 27.1 g 
D) 95.4 g 
E) 47.8 g

Question 9

Calculate the work done by the system when 2 moles of hydrogen gas is produced by the following reaction in a flask fitted with an inflatable balloon.
Zn(s)+2HCl(aq)= ZnCl2(aq)+ H2(g)

Accepted Answer

A) +4.8 kJ 
B) -4.8 kJ 
C) 0 kJ 
D) 2.0kJ

Question 10

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

Accepted Answer

A) 50.0 g Al,CAl = 0.903 J/g°C 
B) 50.0 g Cu,CCu = 0.385 J/g°C 
C) 25.0 g granite,Cgranite = 0.79 J/g°C 
D) 25.0 g Au,CAu = 0.128 J/g°C 
E) 25.0 g Ag,CAg = 0.235 J/g°C

Question 11

Which of the following processes is endothermic?

Accepted Answer

A) the freezing of water 
B) the combustion of propane 
C) a hot cup of coffee (system)cooling on a countertop 
D) the chemical reaction in a "hot pack" often used to treat sore muscles 
E) the vaporization of rubbing alcohol

Question 12

The specific heat capacity of liquid water is 4.18 J/g ∙ K.How many joules of heat are needed to raise the temperature of 5.00 g of water from 25.1°C to 65.3°C?

Accepted Answer

A) 48.1 J 
B) 840 J 
C) 1.89 × 
J 
D) 2.08 × 
J 
E) 54.4 J

Question 13

Match the following.
--w

Accepted Answer

A) work done by the system on the surroundings 
B) system gains thermal energy from surroundings 
C) energy flows out of system into the surroundings 
D) system loses thermal energy to surroundings 
E) work done on the system by the surroundings
F)energy flows into the system from the surroundings

Question 14

In the following reaction,energy is given off.Where does the energy go?
C(s)+O2 (g)= CO2(g)

Accepted Answer

A) to the reactants 
B) to the products 
C) to the system 
D) to the surroundings

Question 15

According to the following reaction,how much energy is required to decompose 55.0 kg of Fe3O4? The molar mass of Fe3O4 is 231.55 g/mol.
Fe3O4(s)→ 3 Fe(s)+ 2 O2(g)ΔH°rxn = +1118 kJ

Accepted Answer

A) 1.10 × 106 kJ 
B) 2.38 × 102 kJ 
C) 2.66 × 105 kJ 
D) 1.12 × 103 kJ 
E) 3.44 × 104 kJ

Question 16

Calculate the amount of heat (in kJ)necessary to raise the temperature of 47.8 g benzene by 57.0 K.The specific heat capacity of benzene is 1.05 J/g°C

Accepted Answer

A) 1.61 kJ 
B) 16.6 kJ 
C) 2.59 kJ 
D) 2.86 kJ 
E) 3.85 kJ

Question 17

Where does the energy absorbed during an endothermic reaction go?

Accepted Answer

The answer of Where does the energy absorbed during an...

Question 18

When 1.50 mol of CH4(g)reacts with excess Cl2(g)at constant pressure according to the chemical equation shown below,1062 kJ of heat are released.Calculate the value of ΔH for this reaction,as written.
2 CH4(g)+ 3 Cl2(g)→ 2 CHCl3(l)+ 3 H2(g)ΔH = ?

Accepted Answer

A) -1420 kJ 
B) -708 kJ 
C) +708 kJ 
D) +1420 kJ

Question 19

The combustion of titanium with oxygen produces titanium dioxide:
Ti(s)+ O2(g)→ TiO2(s)
When 2.060 g of titanium is combusted in a bomb calorimeter,the temperature of the calorimeter increases from 25.00°C to 91.60°C.In a separate experiment,the heat capacity of the calorimeter is measured to be 9.84 kJ/K.The heat of reaction for the combustion of a mole of Ti in this calorimeter is ________ kJ/mol.

Accepted Answer

A) 14.3 
B) 19.6 
C) -311 
D) -0.154 
E) -1.52 × 104

Question 20

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

Exam 6: Thermochemistry

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 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.

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 motor does 30 kJ of work and loses 4 kJ as heat to the surroundings.What is the change in the internal energy of the motor?

An ice cube melts and cools the surrounding beverage.(The ice cube is the system. ) Which of the following statement is correct?

The enthalpy of combustion of gasoline (C₈H₁₈) is 5471 kJ mol^-1.How much heat will be produced by burning 1 gallon of gasoline at 25^°C? (Density of gasoline = 0.703 g/mL;1gallon = 3.78 L)

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

According to the following thermochemical equation,what mass of H₂O (in g) must form in order to produce 488 kJ of energy? SiO₂(s) + 4 HF(g) → SiF₄(g) + 2 H₂O(l) ΔH°_rxn= -184 kJ

Calculate the work done by the system when 2 moles of hydrogen gas is produced by the following reaction in a flask fitted with an inflatable balloon. Zn(s) +2HCl(aq) = ZnCl₂(aq) + H₂(g)

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

Which of the following processes is endothermic?

The specific heat capacity of liquid water is 4.18 J/g ∙ K.How many joules of heat are needed to raise the temperature of 5.00 g of water from 25.1°C to 65.3°C?

Match the following. --w

In the following reaction,energy is given off.Where does the energy go? C(s) +O₂(g) = CO₂(g)

According to the following reaction,how much energy is required to decompose 55.0 kg of Fe₃O₄? The molar mass of Fe₃O₄is 231.55 g/mol. Fe₃O₄(s) → 3 Fe(s) + 2 O₂(g) ΔH°_rxn= +1118 kJ

Calculate the amount of heat (in kJ) necessary to raise the temperature of 47.8 g benzene by 57.0 K.The specific heat capacity of benzene is 1.05 J/g°C

Where does the energy absorbed during an endothermic reaction go?

When 1.50 mol of CH₄(g) reacts with excess Cl₂(g) at constant pressure according to the chemical equation shown below,1062 kJ of heat are released.Calculate the value of ΔH for this reaction,as written. 2 CH₄(g) + 3 Cl₂(g) → 2 CHCl₃(l) + 3 H₂(g) ΔH = ?

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

Exam 6: Thermochemistry

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 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.

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 motor does 30 kJ of work and loses 4 kJ as heat to the surroundings.What is the change in the internal energy of the motor?

An ice cube melts and cools the surrounding beverage.(The ice cube is the system. ) Which of the following statement is correct?

The enthalpy of combustion of gasoline (C8H18) is 5471 kJ mol-1. How much heat will be produced by burning 1 gallon of gasoline at 25°C? (Density of gasoline = 0.703 g/mL;1gallon = 3.78 L)

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

According to the following thermochemical equation,what mass of H2O (in g) must form in order to produce 488 kJ of energy? SiO2(s) + 4 HF(g) → SiF4(g) + 2 H2O(l) ΔH°rxn = -184 kJ

Calculate the work done by the system when 2 moles of hydrogen gas is produced by the following reaction in a flask fitted with an inflatable balloon. Zn(s) +2HCl(aq) = ZnCl2(aq) + H2(g)

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

Which of the following processes is endothermic?

The specific heat capacity of liquid water is 4.18 J/g ∙ K.How many joules of heat are needed to raise the temperature of 5.00 g of water from 25.1°C to 65.3°C?

Match the following. --w

In the following reaction,energy is given off.Where does the energy go? C(s) +O2 (g) = CO2(g)

According to the following reaction,how much energy is required to decompose 55.0 kg of Fe3O4? The molar mass of Fe3O4 is 231.55 g/mol. Fe3O4(s) → 3 Fe(s) + 2 O2(g) ΔH°rxn = +1118 kJ

Calculate the amount of heat (in kJ) necessary to raise the temperature of 47.8 g benzene by 57.0 K.The specific heat capacity of benzene is 1.05 J/g°C

Where does the energy absorbed during an endothermic reaction go?

When 1.50 mol of CH4(g) reacts with excess Cl2(g) at constant pressure according to the chemical equation shown below,1062 kJ of heat are released.Calculate the value of ΔH for this reaction,as written. 2 CH4(g) + 3 Cl2(g) → 2 CHCl3(l) + 3 H2(g) ΔH = ?

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

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

The enthalpy of combustion of gasoline (C₈H₁₈) is 5471 kJ mol^-1.How much heat will be produced by burning 1 gallon of gasoline at 25^°C? (Density of gasoline = 0.703 g/mL;1gallon = 3.78 L)

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

According to the following thermochemical equation,what mass of H₂O (in g) must form in order to produce 488 kJ of energy? SiO₂(s) + 4 HF(g) → SiF₄(g) + 2 H₂O(l) ΔH°_rxn= -184 kJ

Calculate the work done by the system when 2 moles of hydrogen gas is produced by the following reaction in a flask fitted with an inflatable balloon. Zn(s) +2HCl(aq) = ZnCl₂(aq) + H₂(g)

In the following reaction,energy is given off.Where does the energy go? C(s) +O₂(g) = CO₂(g)

According to the following reaction,how much energy is required to decompose 55.0 kg of Fe₃O₄? The molar mass of Fe₃O₄is 231.55 g/mol. Fe₃O₄(s) → 3 Fe(s) + 2 O₂(g) ΔH°_rxn= +1118 kJ

When 1.50 mol of CH₄(g) reacts with excess Cl₂(g) at constant pressure according to the chemical equation shown below,1062 kJ of heat are released.Calculate the value of ΔH for this reaction,as written. 2 CH₄(g) + 3 Cl₂(g) → 2 CHCl₃(l) + 3 H₂(g) ΔH = ?

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