Octane (C8H18)undergoes combustion according to the following thermochemical equation: 2C8H18(l)+ 25O2(g) $\rarr$16CO2(g)+ 18H2O(l) $\Delta$H°rxn = -11,020 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 standard enthalpy of formation of octane.

A) -210 kJ/mol B) -11,230 kJ/mol C) 22,040 kJ/mol D) -420 kJ/mol E) 420 kJ/mol A) -210 kJ/mol B) -11,230 kJ/mol C) 22,040 kJ/mol D) -420 kJ/mol E) 420 kJ/mol

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. 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.

Acetylene (C2H2)undergoes combustion in excess oxygen to generate gaseous carbon dioxide and water.Given $\Delta$H°f[CO2(g)] = -393.5 kJ/mol, $\Delta$H°f[H2O(g)] = -241.8 kJ/mol, and $\Delta$H°f [C2H2(g)] = 226.6 kJ/mol, how much energy is released (kJ)when 10.5 moles of acetylene is burned?

A) 2,510.8 kJ B) 26,400 kJ C) 13,200 kJ D) 52,700 kJ E) 9,050 kJ A) 2,510.8 kJ B) 26,400 kJ C) 13,200 kJ D) 52,700 kJ E) 9,050 kJ

Which of the following processes is exothermic, given the following: N2(g)+ 2 O2(g)$\rarr$N2O4(l)$\Delta$H° = 9.67 kJ/mol N2(g)+ 2 O2(g)$\rarr$2 NO2(g)$\Delta$H° = 67.70 kJ/mol

A) 2 N2(g)+ 4 O2(g)$\rarr$ 2 N2O4(l) B) ½ N2(g)+ O2(g)$\rarr$ ½ N2O4(l) C) N2O4(l)$\rarr$ N2(g)+ 2 O2(g) D) 2 N2(g)+ 4 O2(g)$\rarr$ 2 NO2(g)+ N2O4(l) E) 2 N2(g)+ 4 O2(g)$\rarr$ 4 NO2(g) A) 2 N2(g)+ 4 O2(g)$\rarr$ 2 N2O4(l) B) ½ N2(g)+ O2(g)$\rarr$ ½ N2O4(l) C) N2O4(l)$\rarr$ N2(g)+ 2 O2(g) D) 2 N2(g)+ 4 O2(g)$\rarr$ 2 NO2(g)+ N2O4(l) E) 2 N2(g)+ 4 O2(g)$\rarr$ 4 NO2(g)

Ethanol undergoes combustion in oxygen to produce carbon dioxide gas and liquid water.The standard heat of combustion of ethanol, C2H5OH(l), is -1366.8 kJ/mol.Given that $\Delta$H°f[CO2(g)] = -393.5 kJ/mol and $\Delta$H°f[H2O(l)] = -285.8 kJ/mol, what is the standard enthalpy of formation of ethanol?

A) -687.6 kJ/mol B) -277.6 kJ/mol C) 687.6 kJ/mol D) 1,367 kJ/mol E) 3,010 kJ/mol A) -687.6 kJ/mol B) -277.6 kJ/mol C) 687.6 kJ/mol D) 1,367 kJ/mol E) 3,010 kJ/mol

Find the standard enthalpy of formation of ethylene, C2H4(g), given the following data: heat of combustion of C2H4(g) = -1411 kJ/mol; $\Delta$H°f[CO2(g)] = -393.5 kJ/mol; $\Delta$H°f[H2O(l)] = -285.8 kJ/mol.

A) 52 kJ/mol B) 87 kJ/mol C) 731 kJ/mol D) 1.41 × 103 kJ/mol E) 2.77 × 103 kJ/mol A) 52 kJ/mol B) 87 kJ/mol C) 731 kJ/mol D) 1.41 × 103 kJ/mol E) 2.77 × 103 kJ/mol

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. 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.

Exam 6: Thermochemistry

Octane (C₈H₁₈)undergoes combustion according to the following thermochemical equation: 2C₈H₁₈(l)+ 25O₂(g) $\rarr$ 16CO₂(g)+ 18H₂O(l) $\Delta$ H°_rxn = -11,020 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 standard enthalpy of formation of octane.

(Multiple Choice)

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Question 21

Find $\Delta$ H°_rxn for the reaction CH₄(g)+ 2O₂(g) $\rarr$ CO₂(g)+ 2H₂O(l). [ $\Delta$ H°_f (CH₄(g))= -74.8 kJ/mol; $\Delta$ H°_f (CO₂(g))= -393.5 kJ/mol; $\Delta$ H°_f (H₂O(l))= -285.5 kJ/mol]

(Short Answer)

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Question 22

Thermal energy is

(Multiple Choice)

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Question 23

The heat of solution of NH₄NO₃ is 26.2 kJ/mol.Is heat evolved or absorbed when a solution of NH₄NO₃ is diluted by addition of more water?

(Short Answer)

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Question 24

A beaker contains 115 g of ethanol at 18.2°C.If the ethanol absorbs 1125 J of heat without losing heat to the surroundings, what will be the final temperature of the ethanol? The specific heat of ethanol is 2.46 J/g.°C.

(Multiple Choice)

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Question 25

The heat of solution of calcium chloride CaCl₂ is -82.8 kJ/mol, and the combined heats of hydration of 1.00 mole of gaseous calcium ions and 2.00 mole of gaseous chloride ions is -2327 kJ.What is the lattice energy of calcium chloride?

(Short Answer)

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Question 26

Determine the heat given off to the surroundings when 9.0 g of aluminum reacts according to the equation 2Al + Fe₂O₃ $\rarr$ Al₂O₃ + 2Fe, $\Delta$ H°_rxn= -849 kJ/mol.

(Multiple Choice)

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Question 27

A 22.0 g block of copper at 45°C absorbs 2.50 kJ of heat.Given the specific heat of Cu is 0.385 J/g·°C what will be the final temperature of the Cu?

(Multiple Choice)

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Question 28

The specific heat of gold is 0.129 J/g·°C.What is the molar heat capacity of gold?

(Multiple Choice)

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Question 29

Acetylene (C₂H₂)undergoes combustion in excess oxygen to generate gaseous carbon dioxide and water.Given $\Delta$ H°_f[CO₂(g)] = -393.5 kJ/mol, $\Delta$ H°_f[H₂O(g)] = -241.8 kJ/mol, and $\Delta$ H°_f[C₂H₂(g)] = 226.6 kJ/mol, how much energy is released (kJ)when 10.5 moles of acetylene is burned?

(Multiple Choice)

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Question 30

For which of these reactions will the difference between $\Delta$ H° and $\Delta$ E° be the greatest?

(Multiple Choice)

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Question 31

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.How much heat was given off during combustion of the sample of pentane?

(Short Answer)

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Question 32

Which of the following processes is exothermic, given the following: N₂(g)+ 2 O₂(g) $\rarr$ N₂O₄(l) $\Delta$ H° = 9.67 kJ/mol N₂(g)+ 2 O₂(g) $\rarr$ 2 NO₂(g) $\Delta$ H° = 67.70 kJ/mol

(Multiple Choice)

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Question 33

A gas is compressed in a cylinder from a volume of 20.0 L to 2.0 L by a constant pressure of 10.0 atm.Calculate the amount of work done on the system.

(Multiple Choice)

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Question 34

Ethanol undergoes combustion in oxygen to produce carbon dioxide gas and liquid water.The standard heat of combustion of ethanol, C₂H₅OH(l), is -1366.8 kJ/mol.Given that $\Delta$ H°_f[CO₂(g)] = -393.5 kJ/mol and $\Delta$ H°_f[H₂O(l)] = -285.8 kJ/mol, what is the standard enthalpy of formation of ethanol?

(Multiple Choice)

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Question 35

A 0.1326 g sample of magnesium was burned in an oxygen bomb calorimeter.The total heat capacity of the calorimeter plus water was 5,760 J/°C.If the temperature rise of the calorimeter with water was 0.570°C, calculate the enthalpy of combustion of magnesium. Mg(s)+ 1/2O₂(g) $\rarr$ MgO(s)

(Multiple Choice)

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Question 36

Aluminum metal has a specific heat of 0.900 J/g·°C.Calculate the amount of heat required to raise the temperature of 10.5 moles of Al from 30.5 °C to 225°C.

(Multiple Choice)

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Question 37

Find the standard enthalpy of formation of ethylene, C₂H₄(g), given the following data: heat of combustion of C₂H₄(g)= -1411 kJ/mol; $\Delta$ H°_f[CO₂(g)] = -393.5 kJ/mol; $\Delta$ H°_f[H₂O(l)] = -285.8 kJ/mol.

(Multiple Choice)

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Question 38

Calculate the amount of heat necessary to raise the temperature of 135.0 g of water from 50.4°F to 85.0°F.The specific heat of water = 4.184 J/g·°C.

(Multiple Choice)

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Question 39

Chemical energy is

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Question 40

Showing 21 - 40 of 118

Exam 6: Thermochemistry

Find Δ\DeltaΔ H°rxn for the reaction CH4(g)+ 2O2(g) →\rarr→ CO2(g)+ 2H2O(l). [ Δ\DeltaΔ H°f (CH4(g))= -74.8 kJ/mol; Δ\DeltaΔ H°f (CO2(g))= -393.5 kJ/mol; Δ\DeltaΔ H°f (H2O(l))= -285.5 kJ/mol]

Thermal energy is

The heat of solution of NH4NO3 is 26.2 kJ/mol.Is heat evolved or absorbed when a solution of NH4NO3 is diluted by addition of more water?

A beaker contains 115 g of ethanol at 18.2°C.If the ethanol absorbs 1125 J of heat without losing heat to the surroundings, what will be the final temperature of the ethanol? The specific heat of ethanol is 2.46 J/g.°C.

The heat of solution of calcium chloride CaCl2 is -82.8 kJ/mol, and the combined heats of hydration of 1.00 mole of gaseous calcium ions and 2.00 mole of gaseous chloride ions is -2327 kJ.What is the lattice energy of calcium chloride?

Determine the heat given off to the surroundings when 9.0 g of aluminum reacts according to the equation 2Al + Fe2O3 →\rarr→ Al2O3 + 2Fe, Δ\DeltaΔ H°rxn= -849 kJ/mol.

A 22.0 g block of copper at 45°C absorbs 2.50 kJ of heat.Given the specific heat of Cu is 0.385 J/g·°C what will be the final temperature of the Cu?

The specific heat of gold is 0.129 J/g·°C.What is the molar heat capacity of gold?

For which of these reactions will the difference between Δ\DeltaΔ H° and Δ\DeltaΔ E° be the greatest?

Which of the following processes is exothermic, given the following: N2(g)+ 2 O2(g) →\rarr→ N2O4(l) Δ\DeltaΔ H° = 9.67 kJ/mol N2(g)+ 2 O2(g) →\rarr→ 2 NO2(g) Δ\DeltaΔ H° = 67.70 kJ/mol

A gas is compressed in a cylinder from a volume of 20.0 L to 2.0 L by a constant pressure of 10.0 atm.Calculate the amount of work done on the system.

A 0.1326 g sample of magnesium was burned in an oxygen bomb calorimeter.The total heat capacity of the calorimeter plus water was 5,760 J/°C.If the temperature rise of the calorimeter with water was 0.570°C, calculate the enthalpy of combustion of magnesium. Mg(s)+ 1/2O2(g) →\rarr→ MgO(s)

Aluminum metal has a specific heat of 0.900 J/g·°C.Calculate the amount of heat required to raise the temperature of 10.5 moles of Al from 30.5 °C to 225°C.

Find the standard enthalpy of formation of ethylene, C2H4(g), given the following data: heat of combustion of C2H4(g) = -1411 kJ/mol; Δ\DeltaΔ H°f[CO2(g)] = -393.5 kJ/mol; Δ\DeltaΔ H°f[H2O(l)] = -285.8 kJ/mol.

Calculate the amount of heat necessary to raise the temperature of 135.0 g of water from 50.4°F to 85.0°F.The specific heat of water = 4.184 J/g·°C.

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Find $\Delta$ H°_rxn for the reaction CH₄(g)+ 2O₂(g) $\rarr$ CO₂(g)+ 2H₂O(l). [ $\Delta$ H°_f (CH₄(g))= -74.8 kJ/mol; $\Delta$ H°_f (CO₂(g))= -393.5 kJ/mol; $\Delta$ H°_f (H₂O(l))= -285.5 kJ/mol]

The heat of solution of NH₄NO₃ is 26.2 kJ/mol.Is heat evolved or absorbed when a solution of NH₄NO₃ is diluted by addition of more water?

The heat of solution of calcium chloride CaCl₂ is -82.8 kJ/mol, and the combined heats of hydration of 1.00 mole of gaseous calcium ions and 2.00 mole of gaseous chloride ions is -2327 kJ.What is the lattice energy of calcium chloride?

Determine the heat given off to the surroundings when 9.0 g of aluminum reacts according to the equation 2Al + Fe₂O₃ $\rarr$ Al₂O₃ + 2Fe, $\Delta$ H°_rxn= -849 kJ/mol.

For which of these reactions will the difference between $\Delta$ H° and $\Delta$ E° be the greatest?

Which of the following processes is exothermic, given the following: N₂(g)+ 2 O₂(g) $\rarr$ N₂O₄(l) $\Delta$ H° = 9.67 kJ/mol N₂(g)+ 2 O₂(g) $\rarr$ 2 NO₂(g) $\Delta$ H° = 67.70 kJ/mol

A 0.1326 g sample of magnesium was burned in an oxygen bomb calorimeter.The total heat capacity of the calorimeter plus water was 5,760 J/°C.If the temperature rise of the calorimeter with water was 0.570°C, calculate the enthalpy of combustion of magnesium. Mg(s)+ 1/2O₂(g) $\rarr$ MgO(s)

Find the standard enthalpy of formation of ethylene, C₂H₄(g), given the following data: heat of combustion of C₂H₄(g)= -1411 kJ/mol; $\Delta$ H°_f[CO₂(g)] = -393.5 kJ/mol; $\Delta$ H°_f[H₂O(l)] = -285.8 kJ/mol.