Question 1

The heat of solution of calcium chloride CaCl2 is -82.8 kJ/mol, and the combined heats of hydration of 1 mole of gaseous calcium ions and 2 mole of gaseous chloride ions is -2327 kJ.What is the lattice energy of calcium chloride?

Accepted Answer

Question 2

The enthalpy of combustion of acetylene C2H2 is described by
C2H2(g)+ (5/2)O2(g)$\rarr$ 2CO2(g)+ H2O(l)$\Delta$H°rxn= -1299 kJ/mol
Calculate the enthalpy of formation of acetylene, given the following enthalpies of formation
F1F1F1S1F1F1F10H°f[CO2(g)] = -393.5 kJ/mol
F1F1F1S1F1F1F10H°f[H2O(l)] = -285.8 kJ/mol

Accepted Answer

The answer of The enthalpy of combustion of acetylene C2H2...

Question 3

At 25°C, the standard enthalpy of formation of anhydrous sodium carbonate is -1130.9 kJ/mol, whereas the standard enthalpy of formation of sodium carbonate monohydrate is -1430.1 kJ/mol. Determine  Δ\DeltaΔ H° at 25°C for the reaction Na2CO3(s) + H2O(l)  →\rarr→ Na2CO3·H2O(s) .
(Given:  Δ\DeltaΔ H°f[H2O(l) ] = -285.8 kJ/mol)

Accepted Answer

A)  -13.4 kJ/mol
B)  -285.8 kJ/mol
C)  -585.0 kJ/mol
D)  -299.2 kJ/mol
E)  -156.3 kJ/mol F) C) and D)
G) A) and C)

Question 4

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?

Accepted Answer

A)  1,797 kJ
B)  1,367 kJ
C)  9.61 * 10-4 kJ
D)  4.78 * 104 kJ
E)  1,040 kJ F) A) and D)
G) All of the above

Question 5

An endothermic reaction causes the surroundings to

Accepted Answer

A)  warm up.
B)  become acidic.
C)  condense.
D)  decrease in temperature.
E)  release CO2.F) A) and D)
G) C) and D)

Question 6

What would be the standard enthalpy change for the reaction of one mole of H2(g)with one mole of Cl2(g)to produce two moles of HCl(g)at standard state conditions?
[$\Delta$H°f (HCl(g))= -92.3 kJ/mol]

Accepted Answer

The answer of What would be the standard enthalpy change...

Question 7

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.F) A) and D)
G) A) and E)

Question 8

At 25°C, the standard enthalpy of formation of KCl(s) is -435.87 kJ/mol. When one mole of KCl(s) is formed by reacting potassium vapor and chlorine gas at 25°C, the standard enthalpy of reaction is -525.86 kJ/mol. Find  Δ\DeltaΔ H° for the sublimation of potassium, K(s)  →\rarr→ K(g) , at 25°C.

Accepted Answer

A)  -345.88 kJ/mol
B)  45.00 kJ/mol
C)  345.88 kJ/mol
D)  89.99 kJ/mol
E)  -525.86 kJ/mol F) A) and B)
G) C) and D)

Question 9

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)  24.53°C
C)  101.8°C
D)  24.40°C
E)  34.25°CF) B) and E)
G) B) and D)

Question 10

At body temperature 2,404 joules of energy are required to evaporate 1.00 g of water.After vigorous exercise, a person feels chilly because the body is giving up heat to evaporate the perspiration.A typical person perspires 25 mL of water after 20.minutes of exercise.How much body heat is this person using to evaporate this water?

Accepted Answer

6.0 * 10<s...

Question 11

A piece of copper with a mass of 218 g has a heat capacity of 83.9 J/°C. What is the specific heat of copper?

Accepted Answer

A)  0.385 J/g·°C
B)  1.83 * 104 J/g·°C
C)  2.60 J/g·°C
D)  1.32 J/g·°C
E)  24.5 J/g·°CF) B) and D)
G) A) and C)

Exam 6: Thermo-Chemistry

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At 25°C, the standard enthalpy of formation of KCl(s) is -435.87 kJ/mol. When one mole of KCl(s) is formed by reacting potassium vapor and chlorine gas at 25°C, the standard enthalpy of reaction is -525.86 kJ/mol. Find $\Delta$ H° for the sublimation of potassium, K(s) $\rarr$ K(g) , at 25°C.

Correct Answer
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Correct Answer
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An endothermic reaction causes the surroundings to

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

Correct Answer
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Correct Answer
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A piece of copper with a mass of 218 g has a heat capacity of 83.9 J/°C. What is the specific heat of copper?

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Correct Answer
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The heat of solution of calcium chloride CaCl₂ is -82.8 kJ/mol, and the combined heats of hydration of 1 mole of gaseous calcium ions and 2 mole of gaseous chloride ions is -2327 kJ.What is the lattice energy of calcium chloride?

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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?

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What would be the standard enthalpy change for the reaction of one mole of H₂(g)with one mole of Cl₂(g)to produce two moles of HCl(g)at standard state conditions? [ $\Delta$ H°_f (HCl(g))= -92.3 kJ/mol]

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Exam 6: Thermo-Chemistry

Correct Answerverified6.0 * 10View AnswerShow Answer

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An endothermic reaction causes the surroundings to

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

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A piece of copper with a mass of 218 g has a heat capacity of 83.9 J/°C. What is the specific heat of copper?

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The enthalpy of combustion of acetylene C2H2 is described by C2H2(g)+ (5/2)O2(g) →\rarr→ 2CO2(g)+ H2O(l) Δ\DeltaΔ H°rxn= -1299 kJ/mol Calculate the enthalpy of formation of acetylene, given the following enthalpies of formation H°f[CO2(g)] = -393.5 kJ/mol H°f[H2O(l)] = -285.8 kJ/mol

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The heat of solution of calcium chloride CaCl2 is -82.8 kJ/mol, and the combined heats of hydration of 1 mole of gaseous calcium ions and 2 mole of gaseous chloride ions is -2327 kJ.What is the lattice energy of calcium chloride?

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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?

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What would be the standard enthalpy change for the reaction of one mole of H2(g)with one mole of Cl2(g)to produce two moles of HCl(g)at standard state conditions? [ Δ\DeltaΔ H°f (HCl(g))= -92.3 kJ/mol]

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6.0 * 10
View Answer

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Correct Answer
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The heat of solution of calcium chloride CaCl₂ is -82.8 kJ/mol, and the combined heats of hydration of 1 mole of gaseous calcium ions and 2 mole of gaseous chloride ions is -2327 kJ.What is the lattice energy of calcium chloride?

Correct Answer
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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?

Correct Answer
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What would be the standard enthalpy change for the reaction of one mole of H₂(g)with one mole of Cl₂(g)to produce two moles of HCl(g)at standard state conditions? [ $\Delta$ H°_f (HCl(g))= -92.3 kJ/mol]

Correct Answer
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