Hydrazine, N2H4, is a liquid used as a rocket fuel. It reacts with oxygen to yield nitrogen gas and water. N2H4( $\ell$ ) + O2(g) ? N2(g) + 2 H2O( $\ell$ ) The reaction of 6.50 g N2H4 evolves 126.2 kJ of heat. Calculate the enthalpy change per mole of hydrazine combusted.

A) -19.4 kJ/mol B) -25.6 kJ/mol C) -126 kJ/mol D) -622 kJ/mol E) -820. kJ/mol A) -19.4 kJ/mol B) -25.6 kJ/mol C) -126 kJ/mol D) -622 kJ/mol E) -820. kJ/mol

Determine the standard enthalpy of formation of Fe2O3(s) given the thermochemical equations below. Fe(s) + 3 H2O( $\ell$ ) ? Fe(OH)3(s) + 3/2 H2(g) ?rH° = +160.9 kJ/mol-rxn H2(g) + 1/2 O2(g) ? H2O( $\ell$ ) ?rH° = -285.8 kJ/mol-rxn Fe2O3(s) + 3 H2O( $\ell$ ) ? 2 Fe(OH)3(s) ?rH° = +288.6 kJ/mol-rxn

A) -252.6 kJ/mol-rxn B) +163.7 kJ/mol-rxn C) -824.2 kJ/mol-rxn D) +33.2 kJ/mol-rxn E) + 890.6 kJ/mol-rxn A) -252.6 kJ/mol-rxn B) +163.7 kJ/mol-rxn C) -824.2 kJ/mol-rxn D) +33.2 kJ/mol-rxn E) + 890.6 kJ/mol-rxn

The following reaction of iron oxide with aluminum is an exothermic reaction. Fe2O3(s) + 2 Al(s) → 2 Fe(s) + Al2O3(s) The reaction of 5.00 g of Fe2O3 with excess Al(s) evolves 26.6 kJ of energy in the form of heat. Calculate the enthalpy change per mole of Fe2O3.

A) -5.32 kJ/mol B) -1.33 × 102 kJ/mol C) -2.12 × 104 kJ/mol D) -2.12 × 102 kJ/mol E) -8.50 × 102 kJ/mol A) -5.32 kJ/mol B) -1.33 × 102 kJ/mol C) -2.12 × 104 kJ/mol D) -2.12 × 102 kJ/mol E) -8.50 × 102 kJ/mol

Exam 6: Principles of Chemical Reactivity: Energy and Chemical Reactions

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A bomb calorimeter has a heat capacity of 2.47 kJ/K. When a 0.103-g sample of a certain hydrocarbon was burned in this calorimeter, the temperature increased by 2.14 K. Calculate the energy of combustion for 1 g of the hydrocarbon.

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Question 41

How much energy is gained by copper when 68.4 g of copper is warmed from 13.4 °C to 78.4 °C? The specific heat capacity of copper is 0.385 J/(g·°C).

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Question 42

One statement of the first law of thermodynamics is that

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Question 43

_____ is used to measure the energy evolved or absorbed as heat in a chemical or physical process.

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Question 44

Specific heat capacity is

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Question 45

Heat capacity is defined as

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Question 46

Which of these physical changes would require the release of energy?

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Question 47

A 170.0-g sample of metal at 83.00°C is added to 170.0 g of H₂O(l) at 15.00°C in an insulated container. The temperature rises to 18.16°C. Neglecting the heat capacity of the container, what is the specific heat capacity of the metal? The specific heat capacity of H₂O(l) is 4.18 J/(g·°C).

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Question 48

What is ?_rH° for the following phase change? LiF(s) ? LiF(l) Substance $\quad \Delta H ^ { \circ } {}_f ( \mathrm {~kJ} / \mathrm { mol } - \mathrm { rxn } )$ $\operatorname { LiF } ( s ) \quad - 616.93$ $\operatorname { LiF } ( l ) \quad - 598.65$

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Question 49

Hydrazine, N₂H₄, is a liquid used as a rocket fuel. It reacts with oxygen to yield nitrogen gas and water. N₂H₄( $\ell$ ) + O₂(g) ? N₂(g) + 2 H₂O( $\ell$ ) The reaction of 6.50 g N₂H₄ evolves 126.2 kJ of heat. Calculate the enthalpy change per mole of hydrazine combusted.

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Question 50

Determine the standard enthalpy of formation of Fe₂O₃(s) given the thermochemical equations below. Fe(s) + 3 H₂O( $\ell$ ) ? Fe(OH)₃(s) + 3/2 H₂(g) ?_rH° = +160.9 kJ/mol-rxn H₂(g) + 1/2 O₂(g) ? H₂O( $\ell$ ) ?_rH° = -285.8 kJ/mol-rxn Fe₂O₃(s) + 3 H₂O( $\ell$ ) ? 2 Fe(OH)₃(s) ?_rH° = +288.6 kJ/mol-rxn

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Question 51

In thermodynamics, a(n) ________ is defined as the object, or collection of objects, being studied. The surroundings include everything else.

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Question 52

Combustion of 2.14 g of liquid benzene (C₆H₆) causes a temperature rise of 16.2 °C in a constant-pressure calorimeter that has a heat capacity of 5.53 kJ/°C. What is ?H for the following reaction? C₆H₆(l) + $\frac { 15 } { 2 }$ O₂(g) ? 6 CO₂(g) + 3 H₂O( $\ell$ )

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Question 53

Calculate ΔU of a gas for a process in which the gas absorbs 45 J of heat and does 11 J of work by expanding.

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Question 54

Many homes are heated using natural gas. The combustion of natural gas converts

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Question 55

It is relatively easy to change the temperature of a substance that

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Question 56

Which one of the following statements is INCORRECT?

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Question 57

Which of the following chemical equations does not correspond to a standard molar enthalpy of formation?

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Question 58

What is the change in internal energy of the system (ΔU) if 65 kJ of heat energy is evolved by the system and 62 kJ of work is done on the system for a certain process?

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Question 59

The following reaction of iron oxide with aluminum is an exothermic reaction. Fe₂O₃(s) + 2 Al(s) → 2 Fe(s) + Al₂O₃(s) The reaction of 5.00 g of Fe₂O₃ with excess Al(s) evolves 26.6 kJ of energy in the form of heat. Calculate the enthalpy change per mole of Fe₂O₃.

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Question 60

Showing 41 - 60 of 69

Exam 6: Principles of Chemical Reactivity: Energy and Chemical Reactions

A bomb calorimeter has a heat capacity of 2.47 kJ/K. When a 0.103-g sample of a certain hydrocarbon was burned in this calorimeter, the temperature increased by 2.14 K. Calculate the energy of combustion for 1 g of the hydrocarbon.

How much energy is gained by copper when 68.4 g of copper is warmed from 13.4 °C to 78.4 °C? The specific heat capacity of copper is 0.385 J/(g·°C).

One statement of the first law of thermodynamics is that

_____ is used to measure the energy evolved or absorbed as heat in a chemical or physical process.

Specific heat capacity is

Heat capacity is defined as

Which of these physical changes would require the release of energy?

A 170.0-g sample of metal at 83.00°C is added to 170.0 g of H2O(l) at 15.00°C in an insulated container. The temperature rises to 18.16°C. Neglecting the heat capacity of the container, what is the specific heat capacity of the metal? The specific heat capacity of H2O(l) is 4.18 J/(g·°C).

Hydrazine, N2H4, is a liquid used as a rocket fuel. It reacts with oxygen to yield nitrogen gas and water. N2H4( ℓ\ellℓ ) + O2(g) ? N2(g) + 2 H2O( ℓ\ellℓ ) The reaction of 6.50 g N2H4 evolves 126.2 kJ of heat. Calculate the enthalpy change per mole of hydrazine combusted.

In thermodynamics, a(n) ________ is defined as the object, or collection of objects, being studied. The surroundings include everything else.

Combustion of 2.14 g of liquid benzene (C6H6) causes a temperature rise of 16.2 °C in a constant-pressure calorimeter that has a heat capacity of 5.53 kJ/°C. What is ?H for the following reaction? C6H6(l) + 152\frac { 15 } { 2 }215​ O2(g) ? 6 CO2(g) + 3 H2O( ℓ\ellℓ )

Calculate ΔU of a gas for a process in which the gas absorbs 45 J of heat and does 11 J of work by expanding.

Many homes are heated using natural gas. The combustion of natural gas converts

It is relatively easy to change the temperature of a substance that

Which one of the following statements is INCORRECT?

Which of the following chemical equations does not correspond to a standard molar enthalpy of formation?

What is the change in internal energy of the system (ΔU) if 65 kJ of heat energy is evolved by the system and 62 kJ of work is done on the system for a certain process?

The following reaction of iron oxide with aluminum is an exothermic reaction. Fe2O3(s) + 2 Al(s) → 2 Fe(s) + Al2O3(s) The reaction of 5.00 g of Fe2O3 with excess Al(s) evolves 26.6 kJ of energy in the form of heat. Calculate the enthalpy change per mole of Fe2O3.

Basic Concepts of Chemistry

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Intermolecular Forces and Liquids

The Solid State

Solutions and Their Behavior

Chemical Kinetics: the Rates of Chemical Reactions

Principles of Chemical Reactivity: Equilibria

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Principles of Chemical Reactivity: Other Aspects of Aqueous Equilibria

Principles of Chemical Reactivity: Entropy and Free Energy

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Carbon: Not Just Another Element

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A 170.0-g sample of metal at 83.00°C is added to 170.0 g of H₂O(l) at 15.00°C in an insulated container. The temperature rises to 18.16°C. Neglecting the heat capacity of the container, what is the specific heat capacity of the metal? The specific heat capacity of H₂O(l) is 4.18 J/(g·°C).

Hydrazine, N₂H₄, is a liquid used as a rocket fuel. It reacts with oxygen to yield nitrogen gas and water. N₂H₄( $\ell$ ) + O₂(g) ? N₂(g) + 2 H₂O( $\ell$ ) The reaction of 6.50 g N₂H₄ evolves 126.2 kJ of heat. Calculate the enthalpy change per mole of hydrazine combusted.

Combustion of 2.14 g of liquid benzene (C₆H₆) causes a temperature rise of 16.2 °C in a constant-pressure calorimeter that has a heat capacity of 5.53 kJ/°C. What is ?H for the following reaction? C₆H₆(l) + $\frac { 15 } { 2 }$ O₂(g) ? 6 CO₂(g) + 3 H₂O( $\ell$ )

The following reaction of iron oxide with aluminum is an exothermic reaction. Fe₂O₃(s) + 2 Al(s) → 2 Fe(s) + Al₂O₃(s) The reaction of 5.00 g of Fe₂O₃ with excess Al(s) evolves 26.6 kJ of energy in the form of heat. Calculate the enthalpy change per mole of Fe₂O₃.