Question 1

Heat is

Accepted Answer

A) a measure of temperature. 
B) a measure of the change in temperature. 
C) a measure of thermal energy. 
D) a measure of thermal energy transferred between two bodies at different temperature. 
A) a measure of temperature. 
B) a measure of the change in temperature. 
C) a measure of thermal energy. 
D) a measure of thermal energy transferred between two bodies at different temperature.

Question 2

Calculate the heat released (kJ)in the reaction of 3.50 g of acetylene (C2H2)and excess hydrogen gas to form ethane gas:
C2H2(g)+ 2H2(g)$\rarr$C2H6(g)
Given:
2C2H2(g)+ 5O2(g)$\rarr$4CO2(g)+ 2H2O(g),$\Delta$H = -2320 kJ/mol
2C2H6(g)+ 7O2(g)$\rarr$4CO2(g)+ 6H2O(g),$\Delta$H = -3040 kJ/mol
2H2(g)+ O2(g)$\rarr$2H2O(g),$\Delta$H = -572 kJ/mol

Accepted Answer

Question 3

The total heat of hydration of 1.00 mol of gas phase Li+ ions and Cl - ions is -865 kJ.The lattice energy of LiCl(s)is 828 kJ/mol.Calculate the heat of solution of LiCl.

Accepted Answer

A) -1,693 kJ/mol 
B) -37 kJ/mol 
C) 37 kJ/mol 
D) 1,693 kJ/mol 
E) None of these 
A) -1,693 kJ/mol 
B) -37 kJ/mol 
C) 37 kJ/mol 
D) 1,693 kJ/mol 
E) None of these

Question 4

Given 2Al(s)+ (3/2)O2(g)$\rarr$Al2O3(s), $\Delta$H°f = -1,670 kJ/mol for Al2O3 (s). Determine $\Delta$H° for the reaction 2Al2O3(s)$\rarr$ 4Al(s)+ 3O2(g).

Accepted Answer

A) -3,340 kJ/mol 
B) -1,670 kJ/mol 
C) -835 kJ/mol 
D) 1,670 kJ/mol 
E) 3,340 kJ/mol 
A) -3,340 kJ/mol 
B) -1,670 kJ/mol 
C) -835 kJ/mol 
D) 1,670 kJ/mol 
E) 3,340 kJ/mol

Question 5

Given the specific heat for aluminum is 0.900 J/g·°C, how much heat is released when a 3.8 g sample of Al cools from 450.0°C to 25°C.

Accepted Answer

A) 54 J 
B) 60 J 
C) 86 J 
D) 1.5 kJ 
E) 1.7 kJ 
A) 54 J 
B) 60 J 
C) 86 J 
D) 1.5 kJ 
E) 1.7 kJ

Question 6

The specific heat of silver is 0.235 J/g·°C.How many joules of heat are required to heat a 75 g silver spoon from 20°C to 35°C?

Accepted Answer

The answer of The specific heat of silver is 0.235...

Question 7

Glycine, C2H5O2N, is important for biological energy.The combustion reaction of glycine is given by the equation 4C2H5O2N(s)+ 9O2(g) $\rarr$8CO2(g)+ 10H2O(l)+ 2N2(g)$\Delta$H°rxn = -3857 kJ/mol
Given that $\Delta$H°f[CO2(g)] = -393.5 kJ/mol and $\Delta$H°f[H2O(l)] = -285.8 kJ/mol, calculate the enthalpy of formation of glycine.

Accepted Answer

A) -3,178 kJ/mol 
B) -964 kJ/mol 
C) -537.2 kJ/mol 
D) -268.2 kJ/mol 
E) 2,149 kJ/mol 
A) -3,178 kJ/mol 
B) -964 kJ/mol 
C) -537.2 kJ/mol 
D) -268.2 kJ/mol 
E) 2,149 kJ/mol

Question 8

The heat of combustion of propane, C3H8, 2220 kJ/mol.The specific heat of copper is 0.385 J/g.°C.How many grams of propane must be burned to raise the temperature of a 10.0 kg block of copper from 25.0°C to 65.0°C, assuming none of the heat is lost to the surroundings

Accepted Answer

Question 9

The value of $\Delta$H°rxn for the following reaction is -6535 kJ/mol.
2C6H6(l)+ 15O2(g)$\rarr$ 12CO2(g)+ 6H2O(g)
How many kilojoules of heat will be evolved during the combustion of 16.0 g of C6H6(l)?

Accepted Answer

Question 10

How many grams of ethylene (C2H4)would have to be burned to produce 450 kJ of heat?
C2H4(g)+ 3O2(g) $\rarr$ 2CO2(g)+ H2O(l),$\Delta$H°rxn = -1411 kJ/mol

Accepted Answer

Question 11

A 0.1946 g piece of magnesium metal is burned in a constant-volume calorimeter that has a heat capacity of 1349 J/°C.The calorimeter contains 500.g of water and the temperature rise is 1.40°C.Calculate the heat of combustion of magnesium metal in kJ/g, given that the specific heat of water = 4.184 J/g·°C.

Accepted Answer

The answer of A 0.1946 g piece of magnesium metal...

Question 12

A 26.2 g piece of copper metal is heated from 21.5°C to 201.6°C.Calculate the amount of heat absorbed by the metal.The specific heat of Cu is 0.385 J/g·°C.

Accepted Answer

The answer of A 26.2 g piece of copper metal...

Question 13

The heat of solution of ammonium chloride is 15.2 kJ/mol.If a 6.134 g sample of NH4Cl is added to 65.0 mL of water in a calorimeter at 24.5°C, what is the minimum temperature reached by the solution? (The specific heat of water = 4.18 J/g·°C; the heat capacity of the calorimeter = 365.J/°C.)

Accepted Answer

A) 18.6°C 
B) 19.7°C 
C) 21.9°C 
D) 27.1°C 
E) 30.4°C 
A) 18.6°C 
B) 19.7°C 
C) 21.9°C 
D) 27.1°C 
E) 30.4°C

Question 14

Calculate the heat required when 2.50 mol of A reacts with excess B and A2B according to the reaction: 2A + B + A2B $\rarr$ 2AB + A2
 Given:

Accepted Answer

A) 10.0 kJ 
B) 12.5 kJ 
C) 25.0 kJ 
D) 35.0 kJ 
E) 62.5 kJ 
A) 10.0 kJ 
B) 12.5 kJ 
C) 25.0 kJ 
D) 35.0 kJ 
E) 62.5 kJ

Question 15

When 18.5 g of HgO(s)is decomposed to form Hg(l)and O2(g), 7.75 kJ of heat is absorbed at standard-state conditions.What is the standard enthalpy of formation ($\Delta$H°f)of HgO(s)?

Accepted Answer

A) -90.7 kJ/mol 
B) -7.75 kJ/mol 
C) 0.419 kJ/mol 
D) 27.9 kJ/mol 
E) 143 kJ/mol 
A) -90.7 kJ/mol 
B) -7.75 kJ/mol 
C) 0.419 kJ/mol 
D) 27.9 kJ/mol 
E) 143 kJ/mol

Question 16

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

Accepted Answer

A) CO2(g) 
B) O3(g) 
C) Cl-(aq) 
D) NH3(aq) 
E) I2(s) 
A) CO2(g) 
B) O3(g) 
C) Cl-(aq) 
D) NH3(aq) 
E) I2(s)

Question 17

Suppose a 50.0 g block of silver (specific heat = 0.2350 J/g·°C)at 100°C is placed in contact with a 50.0 g block of iron (specific heat = 0.4494 J/g·°C)at 0°C, and the two blocks are insulated from the rest of the universe.The final temperature of the two blocks

Accepted Answer

A) will be higher than 50°C. 
B) will be lower than 50°C. 
C) will be exactly 50°C. 
D) is unrelated to the composition of the blocks. 
E) cannot be predicted. 
A) will be higher than 50°C. 
B) will be lower than 50°C. 
C) will be exactly 50°C. 
D) is unrelated to the composition of the blocks. 
E) cannot be predicted.

Question 18

The combustion of pentane produces heat according to the equation C5H12(l)+ 8O2(g)$\rarr$5CO2(g)+ 6H2O(l),$\Delta$H°rxn= -3,510 kJ/mol
How many grams of CO2 are produced per 2.50 × 103 kJ of heat released?

Accepted Answer

A) 0.0809 g 
B) 3.56 g 
C) 31.3 g 
D) 157 g 
E) 309 g 
A) 0.0809 g 
B) 3.56 g 
C) 31.3 g 
D) 157 g 
E) 309 g

Question 19

At 25°C, the following heats of reaction are known:

At the same temperature, use the above data to calculate the heat released (kJ)when 3.40 moles of ClF(g)reacts with excess F2: ClF(g)+ F2(g)$\rarr$ ClF3(g)

Accepted Answer

A) 109 kJ 
B) 233 kJ 
C) 370.kJ 
D) 465 kJ 
E) 1,580 kJ 
A) 109 kJ 
B) 233 kJ 
C) 370.kJ 
D) 465 kJ 
E) 1,580 kJ

Question 20

The heat of solution of LiCl is -37.1 kJ/mol, and the lattice energy of LiCl(s)is 828 kJ/mol.Calculate the total heat of hydration of 1.00 mol of gas phase Li+ ions and Cl- ions.

Accepted Answer

A) -865 kJ 
B) -791 kJ 
C) 791 kJ 
D) 865 kJ 
E) None of these. 
A) -865 kJ 
B) -791 kJ 
C) 791 kJ 
D) 865 kJ 
E) None of these.

Heat is

The total heat of hydration of 1.00 mol of gas phase Li⁺ ions and Cl^- ions is -865 kJ.The lattice energy of LiCl(s)is 828 kJ/mol.Calculate the heat of solution of LiCl.

Given 2Al(s)+ (3/2)O₂(g) $\rarr$ Al₂O₃(s), $\Delta$ H°_f = -1,670 kJ/mol for Al₂O₃ (s). Determine $\Delta$ H° for the reaction 2Al₂O₃(s) $\rarr$ 4Al(s)+ 3O₂(g).

Given the specific heat for aluminum is 0.900 J/g·°C, how much heat is released when a 3.8 g sample of Al cools from 450.0°C to 25°C.

The specific heat of silver is 0.235 J/g·°C.How many joules of heat are required to heat a 75 g silver spoon from 20°C to 35°C?

The heat of combustion of propane, C₃H₈, 2220 kJ/mol.The specific heat of copper is 0.385 J/g.°C.How many grams of propane must be burned to raise the temperature of a 10.0 kg block of copper from 25.0°C to 65.0°C, assuming none of the heat is lost to the surroundings

The value of $\Delta$ H°_rxn for the following reaction is -6535 kJ/mol. 2C₆H₆(l)+ 15O₂(g) $\rarr$ 12CO₂(g)+ 6H₂O(g) How many kilojoules of heat will be evolved during the combustion of 16.0 g of C₆H₆(l)?

How many grams of ethylene (C₂H₄)would have to be burned to produce 450 kJ of heat? C₂H₄(g)+ 3O₂(g) $\rarr$ 2CO₂(g)+ H₂O(l), $\Delta$ H°_rxn = -1411 kJ/mol

A 26.2 g piece of copper metal is heated from 21.5°C to 201.6°C.Calculate the amount of heat absorbed by the metal.The specific heat of Cu is 0.385 J/g·°C.

The heat of solution of ammonium chloride is 15.2 kJ/mol.If a 6.134 g sample of NH₄Cl is added to 65.0 mL of water in a calorimeter at 24.5°C, what is the minimum temperature reached by the solution? (The specific heat of water = 4.18 J/g·°C; the heat capacity of the calorimeter = 365.J/°C.)

When 18.5 g of HgO(s)is decomposed to form Hg(l)and O₂(g), 7.75 kJ of heat is absorbed at standard-state conditions.What is the standard enthalpy of formation ( $\Delta$ H°_f)of HgO(s)?

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

Suppose a 50.0 g block of silver (specific heat = 0.2350 J/g·°C)at 100°C is placed in contact with a 50.0 g block of iron (specific heat = 0.4494 J/g·°C)at 0°C, and the two blocks are insulated from the rest of the universe.The final temperature of the two blocks

The combustion of pentane produces heat according to the equation C₅H₁₂(l)+ 8O₂(g) $\rarr$ 5CO₂(g)+ 6H₂O(l), $\Delta$ H°_rxn= -3,510 kJ/mol How many grams of CO₂ are produced per 2.50 × 10³ kJ of heat released?

The heat of solution of LiCl is -37.1 kJ/mol, and the lattice energy of LiCl(s)is 828 kJ/mol.Calculate the total heat of hydration of 1.00 mol of gas phase Li⁺ ions and Cl^- ions.

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Exam 6: Thermochemistry

Heat is

The total heat of hydration of 1.00 mol of gas phase Li+ ions and Cl - ions is -865 kJ.The lattice energy of LiCl(s)is 828 kJ/mol.Calculate the heat of solution of LiCl.

Given 2Al(s)+ (3/2)O2(g) →\rarr→ Al2O3(s), Δ\DeltaΔ H°f = -1,670 kJ/mol for Al2O3 (s). Determine Δ\DeltaΔ H° for the reaction 2Al2O3(s) →\rarr→ 4Al(s)+ 3O2(g).

Given the specific heat for aluminum is 0.900 J/g·°C, how much heat is released when a 3.8 g sample of Al cools from 450.0°C to 25°C.

The specific heat of silver is 0.235 J/g·°C.How many joules of heat are required to heat a 75 g silver spoon from 20°C to 35°C?

The heat of combustion of propane, C3H8, 2220 kJ/mol.The specific heat of copper is 0.385 J/g.°C.How many grams of propane must be burned to raise the temperature of a 10.0 kg block of copper from 25.0°C to 65.0°C, assuming none of the heat is lost to the surroundings

The value of Δ\DeltaΔ H°rxn for the following reaction is -6535 kJ/mol. 2C6H6(l)+ 15O2(g) →\rarr→ 12CO2(g)+ 6H2O(g) How many kilojoules of heat will be evolved during the combustion of 16.0 g of C6H6(l)?

How many grams of ethylene (C2H4)would have to be burned to produce 450 kJ of heat? C2H4(g)+ 3O2(g) →\rarr→ 2CO2(g)+ H2O(l), Δ\DeltaΔ H°rxn = -1411 kJ/mol

A 26.2 g piece of copper metal is heated from 21.5°C to 201.6°C.Calculate the amount of heat absorbed by the metal.The specific heat of Cu is 0.385 J/g·°C.

The heat of solution of ammonium chloride is 15.2 kJ/mol.If a 6.134 g sample of NH4Cl is added to 65.0 mL of water in a calorimeter at 24.5°C, what is the minimum temperature reached by the solution? (The specific heat of water = 4.18 J/g·°C; the heat capacity of the calorimeter = 365.J/°C.)

Calculate the heat required when 2.50 mol of A reacts with excess B and A2B according to the reaction: 2A + B + A2B →\rarr→ 2AB + A2 Given:

When 18.5 g of HgO(s)is decomposed to form Hg(l)and O2(g), 7.75 kJ of heat is absorbed at standard-state conditions.What is the standard enthalpy of formation ( Δ\DeltaΔ H°f)of HgO(s)?

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

Suppose a 50.0 g block of silver (specific heat = 0.2350 J/g·°C)at 100°C is placed in contact with a 50.0 g block of iron (specific heat = 0.4494 J/g·°C)at 0°C, and the two blocks are insulated from the rest of the universe.The final temperature of the two blocks

The combustion of pentane produces heat according to the equation C5H12(l)+ 8O2(g) →\rarr→ 5CO2(g)+ 6H2O(l), Δ\DeltaΔ H°rxn= -3,510 kJ/mol How many grams of CO2 are produced per 2.50 × 103 kJ of heat released?

At 25°C, the following heats of reaction are known: At the same temperature, use the above data to calculate the heat released (kJ)when 3.40 moles of ClF(g)reacts with excess F2: ClF(g)+ F2(g) →\rarr→ ClF3(g)

The heat of solution of LiCl is -37.1 kJ/mol, and the lattice energy of LiCl(s)is 828 kJ/mol.Calculate the total heat of hydration of 1.00 mol of gas phase Li+ ions and Cl- ions.

Chemistry: the Study of Change

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Mass Relationships in Chemical Reactions

Reactions in Aqueous Solutions

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Quantum Theory and the Electronic Structure of Atoms

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The total heat of hydration of 1.00 mol of gas phase Li⁺ ions and Cl^- ions is -865 kJ.The lattice energy of LiCl(s)is 828 kJ/mol.Calculate the heat of solution of LiCl.

Given 2Al(s)+ (3/2)O₂(g) $\rarr$ Al₂O₃(s), $\Delta$ H°_f = -1,670 kJ/mol for Al₂O₃ (s). Determine $\Delta$ H° for the reaction 2Al₂O₃(s) $\rarr$ 4Al(s)+ 3O₂(g).

The heat of combustion of propane, C₃H₈, 2220 kJ/mol.The specific heat of copper is 0.385 J/g.°C.How many grams of propane must be burned to raise the temperature of a 10.0 kg block of copper from 25.0°C to 65.0°C, assuming none of the heat is lost to the surroundings

The value of $\Delta$ H°_rxn for the following reaction is -6535 kJ/mol. 2C₆H₆(l)+ 15O₂(g) $\rarr$ 12CO₂(g)+ 6H₂O(g) How many kilojoules of heat will be evolved during the combustion of 16.0 g of C₆H₆(l)?

How many grams of ethylene (C₂H₄)would have to be burned to produce 450 kJ of heat? C₂H₄(g)+ 3O₂(g) $\rarr$ 2CO₂(g)+ H₂O(l), $\Delta$ H°_rxn = -1411 kJ/mol

The heat of solution of ammonium chloride is 15.2 kJ/mol.If a 6.134 g sample of NH₄Cl is added to 65.0 mL of water in a calorimeter at 24.5°C, what is the minimum temperature reached by the solution? (The specific heat of water = 4.18 J/g·°C; the heat capacity of the calorimeter = 365.J/°C.)

When 18.5 g of HgO(s)is decomposed to form Hg(l)and O₂(g), 7.75 kJ of heat is absorbed at standard-state conditions.What is the standard enthalpy of formation ( $\Delta$ H°_f)of HgO(s)?

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

The combustion of pentane produces heat according to the equation C₅H₁₂(l)+ 8O₂(g) $\rarr$ 5CO₂(g)+ 6H₂O(l), $\Delta$ H°_rxn= -3,510 kJ/mol How many grams of CO₂ are produced per 2.50 × 10³ kJ of heat released?

The heat of solution of LiCl is -37.1 kJ/mol, and the lattice energy of LiCl(s)is 828 kJ/mol.Calculate the total heat of hydration of 1.00 mol of gas phase Li⁺ ions and Cl^- ions.