Hydrazine,N2H4,is a liquid used as a rocket fuel.It reacts with oxygen to yield nitrogen gas and water. N2H4( )+ O2(g)$\to$N2(g)+ 2 H2O( ) 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

Calculate the energy in the form of heat (in kJ)required to change 71.8 g of liquid water at 25.7 S1U1P1$\circ$S1S1P0C to ice at -16.1 S1U1P1$\circ$S1S1P0C.Assume that no energy in the form of heat is transferred to the environment.(Heat of fusion = 333 J/g; heat of vaporization = 2256 J/g; specific heat capacities: ice = 2.06 J/g.K,liquid water = 4.184 J/g.K)

A) -12.6 kJ B) -7.7 kJ C) -34.0kJ D) -31.6 kJ E) -10.1 kJ A) -12.6 kJ B) -7.7 kJ C) -34.0kJ D) -31.6 kJ E) -10.1 kJ

Determine the enthalpy change for the decomposition of calcium carbonate CaCO3(s)$\to$ CaO(s)+ CO2(g) Given the thermochemical equations below.

A) +48.6 kJ/mol-rxn B) +179.0 kJ/mol-rxn C) +345.5 kJ/mol-rxn D) +441.0 kJ/mol-rxn E) +1711.7 kJ/mol-rxn A) +48.6 kJ/mol-rxn B) +179.0 kJ/mol-rxn C) +345.5 kJ/mol-rxn D) +441.0 kJ/mol-rxn E) +1711.7 kJ/mol-rxn

Determine the standard enthalpy of formation of Fe2O3(s)given the thermochemical equations below.

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

What is the standard enthalpy of formation of BaCO3(s)? BaO(s)+ CO2(g)$\to$ BaCO3(s); $\Delta$H° = -269.3 kJ/mol-rxn

A) -109.3 kJ/mol-rxn B) -429.3 kJ/mol-rxn C) -677.7 kJ/mol-rxn D) -1216.3 kJ/mol-rxn E) 677.7 kJ/mol-rxn A) -109.3 kJ/mol-rxn B) -429.3 kJ/mol-rxn C) -677.7 kJ/mol-rxn D) -1216.3 kJ/mol-rxn E) 677.7 kJ/mol-rxn

What is the minimum mass of ice at 0.0 S1U1P1$\circ$S1S1P0C that must be added to 1.00 kg of water to cool the water from 28.0 S1U1P1$\circ$S1S1P0C to 12.0 S1U1P1$\circ$S1S1P0C? (Heat of fusion = 333 J/g; specific heat capacities: ice = 2.06 J/g.K,liquid water = 4.184 J/g.K)

A) 175 g B) 201 g C) 244 g D) 299 g E) 1140 g A) 175 g B) 201 g C) 244 g D) 299 g E) 1140 g

A 100 g sample of each of the following metals is heated from 35S1U1P1$\circ$S1S1P0C to 45S1U1P1$\circ$S1S1P0C.Which metal absorbs the greatest amount of heat energy?

A) magnesium B) lead C) mercury D) silver E) copper A) magnesium B) lead C) mercury D) silver E) copper

The heat of vaporization of benzene,C6H6,is 30.7 kJ/mol at its boiling point of 80.1 S1U1P1$\circ$S1S1P0C.How much energy in the form of heat is required to vaporize 102 g benzene at its boiling point?

A) 0.302 kJ B) 23.6 kJ C) 24.2 kJ D) 40.1 kJ E) 3.14 $\times$ 103 kJ A) 0.302 kJ B) 23.6 kJ C) 24.2 kJ D) 40.1 kJ E) 3.14 $\times$ 103 kJ

Commercial cold packs consist of solid ammonium nitrate and water.NH4NO3 absorbs 25.69 kJ of heat per mole dissolved in water.In a coffee-cup calorimeter,5.60 g NH4NO3 is dissolved in 100.0 g of water at 22.0 S1U1P1$\circ$S1S1P0C.What is the final temperature of the solution? Assume that the solution has a specific heat capacity of 4.18 J/g.K.

A) 0.0 S1U1P1$\circ$S1S1P0C B) 17.9 S1U1P1$\circ$S1S1P0C C) 11.6 S1U1P1$\circ$S1S1P0C D) -54.8 S1U1P1$\circ$S1S1P0C E) 26.1 S1U1P1$\circ$S1S1P0C A) 0.0 S1U1P1$\circ$S1S1P0C B) 17.9 S1U1P1$\circ$S1S1P0C C) 11.6 S1U1P1$\circ$S1S1P0C D) -54.8 S1U1P1$\circ$S1S1P0C E) 26.1 S1U1P1$\circ$S1S1P0C

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

A 41.3-g piece of nickel (s = 0.443 J/(g·°C)),initially at 255.8°C,is added to 144.8 g of a liquid,initially at 23.1°C,in an insulated container.The final temperature of the metal-liquid mixture at equilibrium is 35.4°C.What is the identity of the liquid? Neglect the heat capacity of the container.

(Multiple Choice)

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Question 41

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

(Multiple Choice)

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Question 42

What is $\Delta$ _rH° for the following phase change? $What is \Delta rH° for the following phase change?$

(Multiple Choice)

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Question 43

Which of the following processes will result in the lowest final temperature of the metal-water mixture at when thermal equilibrium is reached? The specific heat capacity of nickel is 0.443 J/(g·°C).The specific heat capacity of water is 4.184 J/(g·°C).

(Multiple Choice)

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Question 44

Internal energy and enthalpy are state functions.What is meant by this statement?

(Essay)

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Question 45

Calculate the energy in the form of heat (in kJ)required to change 71.8 g of liquid water at 25.7 ^$\circ$C to ice at -16.1 ^$\circ$C.Assume that no energy in the form of heat is transferred to the environment.(Heat of fusion = 333 J/g; heat of vaporization = 2256 J/g; specific heat capacities: ice = 2.06 J/g.K,liquid water = 4.184 J/g.K)

(Multiple Choice)

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Question 46

Determine the enthalpy change for the decomposition of calcium carbonate CaCO₃(s) $\to$ CaO(s)+ CO₂(g) Given the thermochemical equations below. $Determine the enthalpy change for the decomposition of calcium carbonate CaCO3(s) \to CaO(s)+ CO2(g) Given the thermochemical equations below.$

(Multiple Choice)

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Question 47

A 170.0-g sample of metal at 79.00°C is added to 170.0 g of H₂O(l)at 14.00°C in an insulated container.The temperature rises to 16.19°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).

(Multiple Choice)

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Question 48

Determine the standard enthalpy of formation of Fe₂O₃(s)given the thermochemical equations below.

(Multiple Choice)

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Question 49

What is the standard enthalpy of formation of BaCO₃(s)? BaO(s)+ CO₂(g) $\to$ BaCO₃(s); $\Delta$ H° = -269.3 kJ/mol-rxn $What is the standard enthalpy of formation of BaCO3(s)? BaO(s)+ CO2(g) \to BaCO3(s); \Delta H° = -269.3 kJ/mol-rxn$

(Multiple Choice)

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Question 50

What is the minimum mass of ice at 0.0 ^$\circ$C that must be added to 1.00 kg of water to cool the water from 28.0 ^$\circ$C to 12.0 ^$\circ$C? (Heat of fusion = 333 J/g; specific heat capacities: ice = 2.06 J/g.K,liquid water = 4.184 J/g.K)

(Multiple Choice)

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Question 51

Calculate $\Delta$ U of a gas for a process in which the gas absorbs 19 J of heat and does 49 J of work by expanding.

(Multiple Choice)

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Question 52

A 100 g sample of each of the following metals is heated from 35^$\circ$C to 45^$\circ$C.Which metal absorbs the greatest amount of heat energy? $A 100 g sample of each of the following metals is heated from 35 \circ C to 45 \circ C.Which metal absorbs the greatest amount of heat energy?$

(Multiple Choice)

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Question 53

How much energy is needed to convert 57.5 grams of ice at 0.00°C to liquid water at 75.0°C? Specific heat capacity (ice)= 2.10 J/g°C Specific heat capacity (liquid water)= 4.18 J/g°C Heat of fusion = 333 J/g Heat of vaporization = 2258 J/g

(Multiple Choice)

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Question 54

How much energy is gained by nickel when 18.7 g of nickel is warmed from 20.5 °C to 79.8 °C? The specific heat capacity of nickel is 0.443 J/(g·°C).

(Multiple Choice)

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Question 55

Acetylene,C₂H₂,is a gas used in welding.The molar enthalpy of combustion for acetylene is -2599 kJ.A mass of 0.338 g C₂H₂(g)is combusted in a bomb calorimeter.If the heat capacity of the calorimeter is 729 J/K and it contains 1.150 kg of water,what is the temperature increase of the bomb calorimeter? The specific heat capacity of water is 4.184 J/g.K and the molar mass of acetylene is 26.04 g/mol.

(Multiple Choice)

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Question 56

The heat of vaporization of benzene,C₆H₆,is 30.7 kJ/mol at its boiling point of 80.1 ^$\circ$C.How much energy in the form of heat is required to vaporize 102 g benzene at its boiling point?

(Multiple Choice)

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Question 57

Which of the following statements is/are CORRECT? 1)If a reaction occurs at constant pressure,q = $\Delta$ H. 2)The change in energy for a system is defined as the sum of the energies transferred as heat and work (i.e., $\Delta$ U = q + w). 3)If a reaction occurs at constant volume,q = w

(Multiple Choice)

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Question 58

A hot piece of iron is dropped into a beaker containing colder water.Which of the following statements is/are CORRECT? 1)Energy is transferred as heat from the iron to the water. 2)Thermal equilibrium is attained when the iron and the water reach the same temperature. 3)Thermal energy from the iron is converted to electrostatic energy in the water.

(Multiple Choice)

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Question 59

Commercial cold packs consist of solid ammonium nitrate and water.NH₄NO₃ absorbs 25.69 kJ of heat per mole dissolved in water.In a coffee-cup calorimeter,5.60 g NH₄NO₃ is dissolved in 100.0 g of water at 22.0 ^$\circ$C.What is the final temperature of the solution? Assume that the solution has a specific heat capacity of 4.18 J/g.K.

(Multiple Choice)

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Question 60

Showing 41 - 60 of 74

What is $\Delta$ _rH° for the following phase change? $What is \Delta <sub>r</sub>H° for the following phase change?$

Which of the following processes will result in the lowest final temperature of the metal-water mixture at when thermal equilibrium is reached? The specific heat capacity of nickel is 0.443 J/(g·°C).The specific heat capacity of water is 4.184 J/(g·°C).

Internal energy and enthalpy are state functions.What is meant by this statement?

A 170.0-g sample of metal at 79.00°C is added to 170.0 g of H₂O(l)at 14.00°C in an insulated container.The temperature rises to 16.19°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).

Determine the standard enthalpy of formation of Fe₂O₃(s)given the thermochemical equations below.

What is the standard enthalpy of formation of BaCO₃(s)? BaO(s)+ CO₂(g) $\to$ BaCO₃(s); $\Delta$ H° = -269.3 kJ/mol-rxn $What is the standard enthalpy of formation of BaCO<sub>3</sub>(s)? BaO(s)+ CO<sub>2</sub>(g) \to BaCO<sub>3</sub>(s); \Delta H° = -269.3 kJ/mol-rxn$

What is the minimum mass of ice at 0.0 ^$\circ$C that must be added to 1.00 kg of water to cool the water from 28.0 ^$\circ$C to 12.0 ^$\circ$C? (Heat of fusion = 333 J/g; specific heat capacities: ice = 2.06 J/g.K,liquid water = 4.184 J/g.K)

Calculate $\Delta$ U of a gas for a process in which the gas absorbs 19 J of heat and does 49 J of work by expanding.

How much energy is needed to convert 57.5 grams of ice at 0.00°C to liquid water at 75.0°C? Specific heat capacity (ice)= 2.10 J/g°C Specific heat capacity (liquid water)= 4.18 J/g°C Heat of fusion = 333 J/g Heat of vaporization = 2258 J/g

How much energy is gained by nickel when 18.7 g of nickel is warmed from 20.5 °C to 79.8 °C? The specific heat capacity of nickel is 0.443 J/(g·°C).

The heat of vaporization of benzene,C₆H₆,is 30.7 kJ/mol at its boiling point of 80.1 ^$\circ$C.How much energy in the form of heat is required to vaporize 102 g benzene at its boiling point?

Which of the following statements is/are CORRECT? 1)If a reaction occurs at constant pressure,q = $\Delta$ H. 2)The change in energy for a system is defined as the sum of the energies transferred as heat and work (i.e., $\Delta$ U = q + w). 3)If a reaction occurs at constant volume,q = w

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

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

What is Δ\DeltaΔ rH° for the following phase change?

Which of the following processes will result in the lowest final temperature of the metal-water mixture at when thermal equilibrium is reached? The specific heat capacity of nickel is 0.443 J/(g·°C).The specific heat capacity of water is 4.184 J/(g·°C).

Internal energy and enthalpy are state functions.What is meant by this statement?

Determine the enthalpy change for the decomposition of calcium carbonate CaCO3(s) →\to→ CaO(s)+ CO2(g) Given the thermochemical equations below.

A 170.0-g sample of metal at 79.00°C is added to 170.0 g of H2O(l)at 14.00°C in an insulated container.The temperature rises to 16.19°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).

Determine the standard enthalpy of formation of Fe2O3(s)given the thermochemical equations below.

What is the standard enthalpy of formation of BaCO3(s)? BaO(s)+ CO2(g) →\to→ BaCO3(s); Δ\DeltaΔ H° = -269.3 kJ/mol-rxn

What is the minimum mass of ice at 0.0 ∘\circ∘ C that must be added to 1.00 kg of water to cool the water from 28.0 ∘\circ∘ C to 12.0 ∘\circ∘ C? (Heat of fusion = 333 J/g; specific heat capacities: ice = 2.06 J/g.K,liquid water = 4.184 J/g.K)

Calculate Δ\DeltaΔ U of a gas for a process in which the gas absorbs 19 J of heat and does 49 J of work by expanding.

A 100 g sample of each of the following metals is heated from 35 ∘\circ∘ C to 45 ∘\circ∘ C.Which metal absorbs the greatest amount of heat energy?

How much energy is needed to convert 57.5 grams of ice at 0.00°C to liquid water at 75.0°C? Specific heat capacity (ice)= 2.10 J/g°C Specific heat capacity (liquid water)= 4.18 J/g°C Heat of fusion = 333 J/g Heat of vaporization = 2258 J/g

How much energy is gained by nickel when 18.7 g of nickel is warmed from 20.5 °C to 79.8 °C? The specific heat capacity of nickel is 0.443 J/(g·°C).

The heat of vaporization of benzene,C6H6,is 30.7 kJ/mol at its boiling point of 80.1 ∘\circ∘ C.How much energy in the form of heat is required to vaporize 102 g benzene at its boiling point?

Which of the following statements is/are CORRECT? 1)If a reaction occurs at constant pressure,q = Δ\DeltaΔ H. 2)The change in energy for a system is defined as the sum of the energies transferred as heat and work (i.e., Δ\DeltaΔ U = q + w). 3)If a reaction occurs at constant volume,q = w

Basic Concepts of Chemistry

Mathlets Review: The Tools of Quantitative Chemistry

Atoms, molecules, and Ions

Chemical Reactions

Stoichiometry: Quantitative Information About Chemical Reactions

The Structure of Atoms

The Structure of Atoms and Periodic Trends

Bonding and Molecular Structure

Bonding and Molecular Structure: Orbital Hybridization and Molecular Orbitals

Gases and Their Properties

Intermolecular Forces and Liquids

The Chemistry of Solids

Solutions and Their Behavior

Chemical Kinetics: the Rates of Chemical Reactions

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What is $\Delta$ _rH° for the following phase change? $What is \Delta <sub>r</sub>H° for the following phase change?$

A 170.0-g sample of metal at 79.00°C is added to 170.0 g of H₂O(l)at 14.00°C in an insulated container.The temperature rises to 16.19°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).

Determine the standard enthalpy of formation of Fe₂O₃(s)given the thermochemical equations below.

What is the standard enthalpy of formation of BaCO₃(s)? BaO(s)+ CO₂(g) $\to$ BaCO₃(s); $\Delta$ H° = -269.3 kJ/mol-rxn $What is the standard enthalpy of formation of BaCO<sub>3</sub>(s)? BaO(s)+ CO<sub>2</sub>(g) \to BaCO<sub>3</sub>(s); \Delta H° = -269.3 kJ/mol-rxn$

What is the minimum mass of ice at 0.0 ^$\circ$C that must be added to 1.00 kg of water to cool the water from 28.0 ^$\circ$C to 12.0 ^$\circ$C? (Heat of fusion = 333 J/g; specific heat capacities: ice = 2.06 J/g.K,liquid water = 4.184 J/g.K)

Calculate $\Delta$ U of a gas for a process in which the gas absorbs 19 J of heat and does 49 J of work by expanding.

The heat of vaporization of benzene,C₆H₆,is 30.7 kJ/mol at its boiling point of 80.1 ^$\circ$C.How much energy in the form of heat is required to vaporize 102 g benzene at its boiling point?

Which of the following statements is/are CORRECT? 1)If a reaction occurs at constant pressure,q = $\Delta$ H. 2)The change in energy for a system is defined as the sum of the energies transferred as heat and work (i.e., $\Delta$ U = q + w). 3)If a reaction occurs at constant volume,q = w