Question 1

Potential energy is

Accepted Answer

A)  the energy stored within the structural units of chemical substances.
B)  the energy associated with the random motion of atoms and molecules.
C)  solar energy, i.e.energy that comes from the sun.
D)  energy available by virtue of an object's position. D

Question 2

Calculate the enthalpy of reaction for H₂(g)+ C₂H₄(g)$\rarr$ C₂H₆(g). [$\Delta$H°_f(C₂H₄(g))= 52.3 kJ/mol; $\Delta$H°_f(C₂H₆(g))= -84.7 kJ/mol]

Accepted Answer

-137 kJ/mol

Question 3

The combustion of butane produces heat according to the equation 2C4H10(g)+ 13O2(g)$\rarr$ 8CO2(g)+ 10H2O(l),$\Delta$H°rxn= -5,314 kJ/mol
How many grams of CO2 are produced per 1.00 × 104 kJ of heat released?

Accepted Answer

A)  23.4 g
B)  44.0 g
C)  82.3 g
D)  187 g
E)  662 g  E

Question 4

A 0.3423 g sample of pentane, C₅H₁₂, was burned in a bomb calorimeter.The temperature of the calorimeter and the 1.000 kg of water contained therein rose from 20.22°C to 22.82°C.The heat capacity of the calorimeter is 2.21 kJ/°C.The heat capacity of water = 4.184 J/g·°C.What is the heat of combustion, in kilojoules, per gram of pentane?

Accepted Answer

The answer of A 0.3423 g sample of pentane, C₅H₁₂,...

Question 5

How much heat (kJ)is evolved when 4.50 g of Fe2O3 is reacted with excess carbon monoxide using the equation below? 
Fe2O3(s)+ 3CO(g)$\rarr$ 2 Fe(s)+ 3 CO2(g) , $\Delta$H°rxn = - 24.8 kJ/mol,

Accepted Answer

A)  0.699 kJ
B)  2.10 kJ
C)  17.9 kJ
D)  24.8 kJ
E)  112 kJ

Question 6

According to the first law of thermodynamics:

Accepted Answer

A)  Energy is neither lost nor gained in any energy transformations.
B)  Perpetual motion is possible.
C)  Energy is conserved in quality but not in quantity.
D)  Energy is being created as time passes.We have more energy in the universe now than when time began.

Question 7

The heat of neutralization of HCl by NaOH is $\Delta$H°_rxn = -56.2 kJ/mol.How much heat is released when 125 mL of 1.750 M HCl is mixed with 195 mL of 0.667 M NaOH?

Accepted Answer

The answer of The heat of neutralization of HCl by...

Question 8

Which of the following has a $\Delta$H°f = 0 kJ/mol?

Accepted Answer

A)  NO(g) 
B)  CS2(l) 
C)  Fe2+(aq) 
D)  H2O(l) 
E)  N2(g)

Question 9

Define specific heat.

Accepted Answer

The answer of Define specific heat....

Question 10

The combustion of one mole of benzene, C₆H₆, in oxygen liberates 3268 kJ of heat.The products of the reaction are carbon dioxide and water.How much heat is given off when 183 g of oxygen are reacted with excess benzene?

Accepted Answer

The answer of The combustion of one mole of benzene,...

Question 11

Styrene, C8H8, is one of the substances used in the production of synthetic rubber.When styrene burns in oxygen to form carbon dioxide and liquid water under standard-state conditions at 25°C, 42.62 kJ are released per gram of styrene.Find the standard enthalpy of formation of styrene at 25°C. (Given: $\Delta$H°f[CO2(g)] = -393.5 kJ/mol, $\Delta$H°f[H2O(l)] = -285.8 kJ/mol, $\Delta$H°f[H2O(g)] = -241.8 kJ/mol)

Accepted Answer

A)  147.8 kJ/mol
B)  323.8 kJ/mol
C)  ~636.7 kJ/mol
D)  ~4249 kJ/mol
E)  ~8730 kJ/mol

Question 12

Ozone (O3)in the atmosphere can be converted to oxygen gas by reaction with nitric oxide (NO).Nitrogen dioxide is also produced in the reaction.What is the enthalpy change when 8.50L of ozone at a pressure of 1.00 atm and 25°C reacts with 12.00 L of nitric oxide at the same initial pressure and temperature? 
[$\Delta$H°f(NO)= 90.4 kJ/mol; 
$\Delta$H°f(NO2)= 33.85 kJ/mol; 
$\Delta$H°f(O3)= 142.2 kJ/mol]

Accepted Answer

A)  -1690 kJ
B)  -167 kJ
C)  -97.6 kJ
D)  -69.2 kJ
E)  -19.7 kJ

Question 13

Ethanol (C2H5OH)burns according to the equation C2H5OH(l)+ 3O2(g) $\rarr$ 2CO2(g)+ 3H2O(l), $\Delta$H°rxn = -1367 kJ/mol.
How much heat is released when 35.0 g of ethanol is burned?

Accepted Answer

A)  9.61 × 10-4 kJ
B)  1,040 kJ
C)  1,367 kJ
D)  1,797 kJ
E)  4.78 × 104 kJ

Question 14

The heat released when one mole of water is formed from the elements is 1,198 kJ.An experiment was conducted that permitted water to form in this manner, and the heat was contained in 2.0 liters of water.The water temperature before the reaction was 34.5°C, and after the reaction it had risen to 52.0°C.How many moles of water were formed? (The specific heat of water is 4.184 J/g·°C.)

Accepted Answer

The answer of The heat released when one mole of...

Question 15

Which of the following processes always results in an increase in the energy of a system?

Accepted Answer

A)  The system loses heat and does work on the surroundings.
B)  The system gains heat and does work on the surroundings.
C)  The system loses heat and has work done on it by the surroundings.
D)  The system gains heat and has work done on it by the surroundings.
E)  None of these is always true.

Question 16

Find the heat absorbed from the surroundings when 15 g of O2 reacts according to the equation O + O2 $\rarr$ O3, $\Delta$H°rxn= -103 kJ/mol.

Accepted Answer

A)  4.6 × 10-3 kJ
B)  32 kJ
C)  48 kJ
D)  96 kJ
E)  110 kJ

Question 17

The enthalpy change when a strong acid is neutralized by strong base is -56.1 kJ/mol.If 12.0 mL of 6.00 M HBr at 21.30°C is mixed with 300.mL of 0.250 M NaOH, also at 21.30°C, what will the maximum temperature reached by the resulting solution? (Assume that there is no heat loss to the container, that the specific heat of the final solution is 4.18 J/g·°C, and that the density of the final solution is that of water.)

Accepted Answer

A)  18.20°C
B)  24.40°C
C)  24.53°C
D)  34.25°C
E)  101.8°C

Question 18

Which of the following processes is endothermic, given the following: S(s)+ O2(g)$\rarr$SO2(g)$\Delta$H = -299 kJ/mol
S(s)+ 3/2 O2(g)$\rarr$SO3(g)$\Delta$H = -395 kJ/mol

Accepted Answer

A)  2 S(s) + 2 O2(g)  →\rarr→  2 SO2(g) 
B)  ½ S(s) + ½ O2(g)  →\rarr→  ½ SO2(g) 
C)  2 S(s) + 5/2 O2(g)  →\rarr→ SO2(g) + SO3(g) 
D)  SO3(g)  →\rarr→  S(s) + 3/2 O2(g) 
E)  2 S(s) + 3 O2(g) F →\rarr→  2 SO3(g)

Question 19

Calculate the amount of work done against an atmospheric pressure of 1.00 atm when 500.0 g of zinc dissolves in excess acid at 30.0°C.
 Zn(s)+ 2H+(aq)$\rarr$Zn2+(aq)+ H2(g)

Accepted Answer

A)  w = +22.4 kJ
B)  w = +24.9 kJ
C)  w = 0
D)  w = -2.52 kJ
E)  w = -19.3 kJ

Question 20

Methanol (CH3OH)burns according to the equation 2CH3OH(l)+ 3O2(g)$\rarr$2CO2(g)+ 4H2O(l), $\Delta$H°rxn = -1454 kJ/mol.
How much heat, in kilojoules, is given off when 75.0 g of methanol is burned?

Accepted Answer

A)  727 kJ
B)  3.22 × 103 kJ
C)  1.45 × 103 kJ
D)  1.70 × 103 kJ
E)  3.41 × 103 kJ

Exam 6: Thermochemistry

Potential energy is

Calculate the enthalpy of reaction for H₂(g)+ C₂H₄(g) $\rarr$ C₂H₆(g). [ $\Delta$ H°_f(C₂H₄(g))= 52.3 kJ/mol; $\Delta$ H°_f(C₂H₆(g))= -84.7 kJ/mol]

The combustion of butane produces heat according to the equation 2C₄H₁₀(g) + 13O₂(g) $\rarr$ 8CO₂(g) + 10H₂O(l) , $\Delta$ H°_rxn= -5,314 kJ/mol How many grams of CO₂ are produced per 1.00 × 10⁴ kJ of heat released?

How much heat (kJ) is evolved when 4.50 g of Fe₂O₃ is reacted with excess carbon monoxide using the equation below? Fe₂O₃(s) + 3CO(g) $\rarr$ 2 Fe(s) + 3 CO₂(g) , $\Delta$ H°_rxn = - 24.8 kJ/mol,

According to the first law of thermodynamics:

The heat of neutralization of HCl by NaOH is $\Delta$ H°_rxn = -56.2 kJ/mol.How much heat is released when 125 mL of 1.750 M HCl is mixed with 195 mL of 0.667 M NaOH?

Which of the following has a $\Delta$ H°_f= 0 kJ/mol?

Define specific heat.

The combustion of one mole of benzene, C₆H₆, in oxygen liberates 3268 kJ of heat.The products of the reaction are carbon dioxide and water.How much heat is given off when 183 g of oxygen are reacted with excess benzene?

Ethanol (C₂H₅OH) burns according to the equation C₂H₅OH(l) + 3O₂(g) $\rarr$ 2CO₂(g) + 3H₂O(l) , $\Delta$ H°_rxn = -1367 kJ/mol. How much heat is released when 35.0 g of ethanol is burned?

Which of the following processes always results in an increase in the energy of a system?

Find the heat absorbed from the surroundings when 15 g of O₂ reacts according to the equation O + O₂ $\rarr$ O₃, $\Delta$ H°_rxn= -103 kJ/mol.

Which of the following processes is endothermic, given the following: S(s) + O₂(g) $\rarr$ SO₂(g) $\Delta$ H = -299 kJ/mol S(s) + 3/2 O₂(g) $\rarr$ SO₃(g) $\Delta$ H = -395 kJ/mol

Calculate the amount of work done against an atmospheric pressure of 1.00 atm when 500.0 g of zinc dissolves in excess acid at 30.0°C. Zn(s) + 2H⁺(aq) $\rarr$ Zn²⁺(aq) + H₂(g)

Methanol (CH₃OH) burns according to the equation 2CH₃OH(l) + 3O₂(g) $\rarr$ 2CO₂(g) + 4H₂O(l) , $\Delta$ H°_rxn = -1454 kJ/mol. How much heat, in kilojoules, is given off when 75.0 g of methanol is burned?

Exam 6: Thermochemistry

Potential energy is

Calculate the enthalpy of reaction for H2(g)+ C2H4(g) →\rarr→ C2H6(g). [ Δ\DeltaΔ H°f(C2H4(g))= 52.3 kJ/mol; Δ\DeltaΔ H°f(C2H6(g))= -84.7 kJ/mol]

The combustion of butane produces heat according to the equation 2C4H10(g) + 13O2(g) →\rarr→ 8CO2(g) + 10H2O(l) , Δ\DeltaΔ H°rxn= -5,314 kJ/mol How many grams of CO2 are produced per 1.00 × 104 kJ of heat released?

How much heat (kJ) is evolved when 4.50 g of Fe2O3 is reacted with excess carbon monoxide using the equation below? Fe2O3(s) + 3CO(g) →\rarr→ 2 Fe(s) + 3 CO2(g) , Δ\DeltaΔ H°rxn = - 24.8 kJ/mol,

According to the first law of thermodynamics:

The heat of neutralization of HCl by NaOH is Δ\DeltaΔ H°rxn = -56.2 kJ/mol.How much heat is released when 125 mL of 1.750 M HCl is mixed with 195 mL of 0.667 M NaOH?

Which of the following has a Δ\DeltaΔ H°f = 0 kJ/mol?

Define specific heat.

The combustion of one mole of benzene, C6H6, in oxygen liberates 3268 kJ of heat.The products of the reaction are carbon dioxide and water.How much heat is given off when 183 g of oxygen are reacted with excess benzene?

Ethanol (C2H5OH) burns according to the equation C2H5OH(l) + 3O2(g) →\rarr→ 2CO2(g) + 3H2O(l) , Δ\DeltaΔ H°rxn = -1367 kJ/mol. How much heat is released when 35.0 g of ethanol is burned?

Which of the following processes always results in an increase in the energy of a system?

Find the heat absorbed from the surroundings when 15 g of O2 reacts according to the equation O + O2 →\rarr→ O3, Δ\DeltaΔ H°rxn= -103 kJ/mol.

Which of the following processes is endothermic, given the following: S(s) + O2(g) →\rarr→ SO2(g) Δ\DeltaΔ H = -299 kJ/mol S(s) + 3/2 O2(g) →\rarr→ SO3(g) Δ\DeltaΔ H = -395 kJ/mol

Calculate the amount of work done against an atmospheric pressure of 1.00 atm when 500.0 g of zinc dissolves in excess acid at 30.0°C. Zn(s) + 2H+(aq) →\rarr→ Zn2+(aq) + H2(g)

Methanol (CH3OH) burns according to the equation 2CH3OH(l) + 3O2(g) →\rarr→ 2CO2(g) + 4H2O(l) , Δ\DeltaΔ H°rxn = -1454 kJ/mol. How much heat, in kilojoules, is given off when 75.0 g of methanol is burned?

Calculate the enthalpy of reaction for H₂(g)+ C₂H₄(g) $\rarr$ C₂H₆(g). [ $\Delta$ H°_f(C₂H₄(g))= 52.3 kJ/mol; $\Delta$ H°_f(C₂H₆(g))= -84.7 kJ/mol]

The combustion of butane produces heat according to the equation 2C₄H₁₀(g) + 13O₂(g) $\rarr$ 8CO₂(g) + 10H₂O(l) , $\Delta$ H°_rxn= -5,314 kJ/mol How many grams of CO₂ are produced per 1.00 × 10⁴ kJ of heat released?

How much heat (kJ) is evolved when 4.50 g of Fe₂O₃ is reacted with excess carbon monoxide using the equation below? Fe₂O₃(s) + 3CO(g) $\rarr$ 2 Fe(s) + 3 CO₂(g) , $\Delta$ H°_rxn = - 24.8 kJ/mol,

The heat of neutralization of HCl by NaOH is $\Delta$ H°_rxn = -56.2 kJ/mol.How much heat is released when 125 mL of 1.750 M HCl is mixed with 195 mL of 0.667 M NaOH?

Which of the following has a $\Delta$ H°_f= 0 kJ/mol?

The combustion of one mole of benzene, C₆H₆, in oxygen liberates 3268 kJ of heat.The products of the reaction are carbon dioxide and water.How much heat is given off when 183 g of oxygen are reacted with excess benzene?

Ethanol (C₂H₅OH) burns according to the equation C₂H₅OH(l) + 3O₂(g) $\rarr$ 2CO₂(g) + 3H₂O(l) , $\Delta$ H°_rxn = -1367 kJ/mol. How much heat is released when 35.0 g of ethanol is burned?

Find the heat absorbed from the surroundings when 15 g of O₂ reacts according to the equation O + O₂ $\rarr$ O₃, $\Delta$ H°_rxn= -103 kJ/mol.

Which of the following processes is endothermic, given the following: S(s) + O₂(g) $\rarr$ SO₂(g) $\Delta$ H = -299 kJ/mol S(s) + 3/2 O₂(g) $\rarr$ SO₃(g) $\Delta$ H = -395 kJ/mol

Calculate the amount of work done against an atmospheric pressure of 1.00 atm when 500.0 g of zinc dissolves in excess acid at 30.0°C. Zn(s) + 2H⁺(aq) $\rarr$ Zn²⁺(aq) + H₂(g)

Methanol (CH₃OH) burns according to the equation 2CH₃OH(l) + 3O₂(g) $\rarr$ 2CO₂(g) + 4H₂O(l) , $\Delta$ H°_rxn = -1454 kJ/mol. How much heat, in kilojoules, is given off when 75.0 g of methanol is burned?