H2S(g) + O2(g) → H2O (liq) + SO2(g) &emsp; &emsp; ΔH° = -562.3 kJ 1/8 S8(s) + O2(g) → SO(g) &emsp; &emsp; ΔH° = -297.0 kJ H2(g) + O2 → H2O (liq) ΔH° = -266.9 kJ Compute ΔH° for H2(g) + 1/8 S8 (s) → H2S(g) in kJ.

A) 562.3 kJ B) 276.6 kJ C) 265.3 kJ D) 20.5 kJ E) -1.6 kJ A) 562.3 kJ B) 276.6 kJ C) 265.3 kJ D) 20.5 kJ E) -1.6 kJ

Using the heat of combustion of methanol as -726.6 kJ and the following data: C(graph) + 1/2O2 → CO(g) &emsp;ΔH° = -110.5 kJ C(graph) + O2(g) → CO2(g)&emsp;ΔH° = -393.5 kJ H2(g) + 1/2O2(g) → H2O(l) &emsp;ΔH° = -285.8 kJ Determine ΔH° for the following reaction: CO(g) + 2 H2(g) → CH3OH(l)

A) -349 kJ B) 157.8 kJ C) -157.8 kJ D) 128 kJ E) -128 kJ A) -349 kJ B) 157.8 kJ C) -157.8 kJ D) 128 kJ E) -128 kJ

What is the work done in joules by the system when H2 expands against a constant pressure of 75 atm at 45.3°C? The change in volume is 24.0 L.

A) 1.8 × 103 J B) -8.2 × 104 J C) 8.2 × 104 J D) 1.8 × 105 J E) -1.8 × 105 J A) 1.8 × 103 J B) -8.2 × 104 J C) 8.2 × 104 J D) 1.8 × 105 J E) -1.8 × 105 J

Consider the reaction: &emsp; &emsp; 4 NH3(g) + 5 O2(g) → 4 NO2(g) + 6 H2O(l) ΔH°f -46.19 &emsp; &emsp; 0.00 &emsp; &emsp; 90.37 &emsp; &emsp; -285.85 kJ/mol Compute ΔH° for this reaction.

A) -622.62 kJ B) 984.10 kJ C) -1168.9 kJ D) -241.67 kJ E) -149.29 kJ A) -622.62 kJ B) 984.10 kJ C) -1168.9 kJ D) -241.67 kJ E) -149.29 kJ

Calculate ΔH°f of octane, C8H18(l), given the enthalpy of combustion of octane to CO2(g) and H2O(l), -5471 kJ/mol, and the standard enthalpies of formation of CO2(g) and H2O(l), -393.5 kJ/mol and -285.8 kJ/mol, respectively.

A) -249.2 kJ/mol B) +4792 kJ/mol C) +249.2 kJ/mol D) -4792 kJ/mol A) -249.2 kJ/mol B) +4792 kJ/mol C) +249.2 kJ/mol D) -4792 kJ/mol

2 LiOH(s) → Li2O(s) + H2O(l) ΔH° = 379.1 kJ LiH(s) + H2O(l) → LiOH(s) + H2(g) ΔH° = -111.0 kJ 2 H2(g) + O2(g) → 2 H2O(l) ΔH° = -285.9 kJ Compute ΔH° in kJ for 2 LiH(s) + O2(g) → Li2O(s) + H2O(l)

A) +125.2 kJ B) -17.7 kJ C) -128.8 kJ D) -303.6 kJ E) + 128.8 kJ A) +125.2 kJ B) -17.7 kJ C) -128.8 kJ D) -303.6 kJ E) + 128.8 kJ

Exam 7: Thermochemistry

A mixture of 125 g of iron and 250 g of water is heated from 25.0°C to 70.0°C. How much heat is absorbed by the mixture? (Specific heat of water = 4.18 J/g °C; iron = 0.473 J/g °C)

(Multiple Choice)

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Question 41

Two solutions, 50.0 mL of 1.00 M BaCl₂(aq) and 50.0 mL of 1.00 M Na₂SO₄(aq), both initially at 21.5°C, are added to a calorimeter with a total heat capacity, after the solutions are added, of 1.10 kJ/°C and the temperature rises to 22.7°C. Determine qrxn per mole of BaSO₄(s) formed in the reaction.

(Multiple Choice)

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Question 42

Choose the INCORRECT statement.

(Multiple Choice)

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Question 43

Calculate the enthalpy change for the following reaction at 25°C. The value of ΔH°f in kJ/mol is given below each species: Al³⁺ (aq) + 3 OH- (aq) → Al(OH)₃(s) -531 -230.0 -1276

(Multiple Choice)

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Question 44

How much work, in joules, is done when the pressure is suddenly released from 2.05 atm to 1.87 atm on 27.5 g of He at 27°C?

(Multiple Choice)

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Question 45

A 12-inch diameter ball of pure cobalt metal at 225°C was placed in 10.0 gal. of water at 15.0°C. What is the final temperature of the water? Assume no heat is lost to the surroundings. (sp ht for cobalt is 0.421 J/g °C, density of cobalt = 8.862 g/cm3, 1 gal. = 3.785 L, 1 in = 2.54 cm, V(sphere) = 4/3 πr3)

(Multiple Choice)

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Question 46

Compute ΔH°rxn for the following reaction. The value of ΔH°f in kJ/mol is given below each species: 2 CaO(s) + 2 SO₂(g) + O₂(g) → 2 CaSO₄(s) -635.5 -296.9 0.0 -1432.7

(Multiple Choice)

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Question 47

How much heat is needed to raise the temperature of 5.28 gal of water from 25.0°C to 88.0°C (1 gal = 3.785 L)?

(Multiple Choice)

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Question 48

H₂S(g) + O₂(g) → H₂O (liq) + SO₂(g) ΔH° = -562.3 kJ 1/8 S₈(s) + O₂(g) → SO(g) ΔH° = -297.0 kJ H₂(g) + O₂ → H₂O (liq) ΔH° = -266.9 kJ Compute ΔH° for H₂(g) + 1/8 S8 (s) → H₂S(g) in kJ.

(Multiple Choice)

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Question 49

What is the heat of combustion in kJ/g of benzoic acid (HC₇H₅O₂) if the initial temperature was 22.62°C, the final temperature was 31.10°C, the heat capacity of the bomb calorimeter was 4.88 kJ/°C, and 1.567 grams were combusted?

(Multiple Choice)

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Question 50

Oxygen gas at 34.5°C is compressed from 45.7 L to 34.5 L against a constant pressure of 750 mmHg. What is the work done in joules by the system?

(Multiple Choice)

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Question 51

Using the heat of combustion of methanol as -726.6 kJ and the following data: C(graph) + 1/2O₂ → CO(g) ΔH° = -110.5 kJ C(graph) + O₂(g) → CO₂(g) ΔH° = -393.5 kJ H₂(g) + 1/2O₂(g) → H₂O(l) ΔH° = -285.8 kJ Determine ΔH° for the following reaction: CO(g) + 2 H₂(g) → CH₃OH(l)

(Multiple Choice)

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Question 52

What is the work done in joules by the system when H₂ expands against a constant pressure of 75 atm at 45.3°C? The change in volume is 24.0 L.

(Multiple Choice)

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Question 53

5.04 × 10^-3 mole of a compound is added to 41.0 g of water in a styrofoam cup and stirred until it dissolves. The temperature of the solution changes from 23.460°C to 23.420°C. What is the heat of solution of the compound expressed in kJ/mol? Assume the specific heat of the solution is 4.18 J/g °C.

(Multiple Choice)

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Question 54

Consider the reaction: 4 NH₃(g) + 5 O₂(g) → 4 NO₂(g) + 6 H₂O(l) ΔH°f -46.19 0.00 90.37 -285.85 kJ/mol Compute ΔH° for this reaction.

(Multiple Choice)

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Question 55

1219 joules of heat raise the temperature of 250 g of metal by 64°C. What is the specific heat in J/(g °C? )

(Multiple Choice)

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Question 56

Calculate ΔH°f of octane, C₈H₁₈(l), given the enthalpy of combustion of octane to CO₂(g) and H₂O(l), -5471 kJ/mol, and the standard enthalpies of formation of CO₂(g) and H₂O(l), -393.5 kJ/mol and -285.8 kJ/mol, respectively.

(Multiple Choice)

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Question 57

How much heat is involved in the complete combustion of 2.50 kg propane, C₃H₈? ΔHcomb = -2219 kJ/mol.

(Multiple Choice)

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Question 58

2 LiOH(s) → Li₂O(s) + H₂O(l) ΔH° = 379.1 kJ LiH(s) + H₂O(l) → LiOH(s) + H₂(g) ΔH° = -111.0 kJ 2 H₂(g) + O₂(g) → 2 H₂O(l) ΔH° = -285.9 kJ Compute ΔH° in kJ for 2 LiH(s) + O₂(g) → Li₂O(s) + H₂O(l)

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Question 59

A system that absorbs heat is an exothermic system.

(True/False)

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Question 60

Showing 41 - 60 of 101

Exam 7: Thermochemistry

A mixture of 125 g of iron and 250 g of water is heated from 25.0°C to 70.0°C. How much heat is absorbed by the mixture? (Specific heat of water = 4.18 J/g °C; iron = 0.473 J/g °C)

Choose the INCORRECT statement.

Calculate the enthalpy change for the following reaction at 25°C. The value of ΔH°f in kJ/mol is given below each species: Al3+ (aq) + 3 OH- (aq) → Al(OH)3(s) -531 -230.0 -1276

How much work, in joules, is done when the pressure is suddenly released from 2.05 atm to 1.87 atm on 27.5 g of He at 27°C?

Compute ΔH°rxn for the following reaction. The value of ΔH°f in kJ/mol is given below each species: 2 CaO(s) + 2 SO2(g) + O2(g) → 2 CaSO4(s) -635.5 -296.9 0.0 -1432.7

How much heat is needed to raise the temperature of 5.28 gal of water from 25.0°C to 88.0°C (1 gal = 3.785 L)?

H2S(g) + O2(g) → H2O (liq) + SO2(g) ΔH° = -562.3 kJ 1/8 S8(s) + O2(g) → SO(g) ΔH° = -297.0 kJ H2(g) + O2 → H2O (liq) ΔH° = -266.9 kJ Compute ΔH° for H2(g) + 1/8 S8 (s) → H2S(g) in kJ.

What is the heat of combustion in kJ/g of benzoic acid (HC7H5O2) if the initial temperature was 22.62°C, the final temperature was 31.10°C, the heat capacity of the bomb calorimeter was 4.88 kJ/°C, and 1.567 grams were combusted?

Oxygen gas at 34.5°C is compressed from 45.7 L to 34.5 L against a constant pressure of 750 mmHg. What is the work done in joules by the system?

Using the heat of combustion of methanol as -726.6 kJ and the following data: C(graph) + 1/2O2 → CO(g) ΔH° = -110.5 kJ C(graph) + O2(g) → CO2(g) ΔH° = -393.5 kJ H2(g) + 1/2O2(g) → H2O(l) ΔH° = -285.8 kJ Determine ΔH° for the following reaction: CO(g) + 2 H2(g) → CH3OH(l)

What is the work done in joules by the system when H2 expands against a constant pressure of 75 atm at 45.3°C? The change in volume is 24.0 L.

Consider the reaction: 4 NH3(g) + 5 O2(g) → 4 NO2(g) + 6 H2O(l) ΔH°f -46.19 0.00 90.37 -285.85 kJ/mol Compute ΔH° for this reaction.

1219 joules of heat raise the temperature of 250 g of metal by 64°C. What is the specific heat in J/(g °C? )

Calculate ΔH°f of octane, C8H18(l), given the enthalpy of combustion of octane to CO2(g) and H2O(l), -5471 kJ/mol, and the standard enthalpies of formation of CO2(g) and H2O(l), -393.5 kJ/mol and -285.8 kJ/mol, respectively.

How much heat is involved in the complete combustion of 2.50 kg propane, C3H8? ΔHcomb = -2219 kJ/mol.

2 LiOH(s) → Li2O(s) + H2O(l) ΔH° = 379.1 kJ LiH(s) + H2O(l) → LiOH(s) + H2(g) ΔH° = -111.0 kJ 2 H2(g) + O2(g) → 2 H2O(l) ΔH° = -285.9 kJ Compute ΔH° in kJ for 2 LiH(s) + O2(g) → Li2O(s) + H2O(l)

A system that absorbs heat is an exothermic system.

Matter - Its Properties and Measurement

Atoms and the Atomic Theory

Chemical Compounds

Chemical Reactions

Introduction to Reactions in Aqueous Solutions

Gases

Electrons in Atoms

The Periodic Table and Some Atomic Properties

Chemical Bonding I: Basic Concepts

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Intermolecular Forces: Liquids and Solids

Solutions and Their Physical Properties

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Principles of Chemical Equilibrium

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Additional Aspects of Acid-Base Equilibria

Solubility and Complex-Ion Equilibria

Spontaneous Change: Entropy and Free Energy

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Main Group Elements I: Groups 1, 2, 13, and 14

Main Group Elements II: Groups 18, 17, 16, 15, and Hydrogen

The Transition Elements

Complex Ions and Coordination Compounds

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Calculate the enthalpy change for the following reaction at 25°C. The value of ΔH°f in kJ/mol is given below each species: Al³⁺ (aq) + 3 OH- (aq) → Al(OH)₃(s) -531 -230.0 -1276

Compute ΔH°rxn for the following reaction. The value of ΔH°f in kJ/mol is given below each species: 2 CaO(s) + 2 SO₂(g) + O₂(g) → 2 CaSO₄(s) -635.5 -296.9 0.0 -1432.7

H₂S(g) + O₂(g) → H₂O (liq) + SO₂(g) ΔH° = -562.3 kJ 1/8 S₈(s) + O₂(g) → SO(g) ΔH° = -297.0 kJ H₂(g) + O₂ → H₂O (liq) ΔH° = -266.9 kJ Compute ΔH° for H₂(g) + 1/8 S8 (s) → H₂S(g) in kJ.

What is the heat of combustion in kJ/g of benzoic acid (HC₇H₅O₂) if the initial temperature was 22.62°C, the final temperature was 31.10°C, the heat capacity of the bomb calorimeter was 4.88 kJ/°C, and 1.567 grams were combusted?

What is the work done in joules by the system when H₂ expands against a constant pressure of 75 atm at 45.3°C? The change in volume is 24.0 L.

Consider the reaction: 4 NH₃(g) + 5 O₂(g) → 4 NO₂(g) + 6 H₂O(l) ΔH°f -46.19 0.00 90.37 -285.85 kJ/mol Compute ΔH° for this reaction.

Calculate ΔH°f of octane, C₈H₁₈(l), given the enthalpy of combustion of octane to CO₂(g) and H₂O(l), -5471 kJ/mol, and the standard enthalpies of formation of CO₂(g) and H₂O(l), -393.5 kJ/mol and -285.8 kJ/mol, respectively.

How much heat is involved in the complete combustion of 2.50 kg propane, C₃H₈? ΔHcomb = -2219 kJ/mol.

2 LiOH(s) → Li₂O(s) + H₂O(l) ΔH° = 379.1 kJ LiH(s) + H₂O(l) → LiOH(s) + H₂(g) ΔH° = -111.0 kJ 2 H₂(g) + O₂(g) → 2 H₂O(l) ΔH° = -285.9 kJ Compute ΔH° in kJ for 2 LiH(s) + O₂(g) → Li₂O(s) + H₂O(l)