Question 1

Which one of the following relationships is always correct?

Accepted Answer

A)  potential energy + kinetic energy = constant 
B)  E = q + w 
C)  ($\Delta$E = $\Delta$H - P $\Delta$V) 
D)  H = E + PV 
E)  ($\Delta$H = qv) 
A)  potential energy + kinetic energy = constant 
B)  E = q + w 
C)  ($\Delta$E = $\Delta$H - P $\Delta$V) 
D)  H = E + PV 
E)  ($\Delta$H = qv)

Question 2

Calcium hydroxide, which reacts with carbon dioxide to form calcium carbonate, was used by the ancient Romans as mortar in stone structures. The reaction for this process is:   What is the enthalpy change if 3.8 mol of calcium carbonate is formed?

Accepted Answer

A)  -18 kJ 
B)  -69 kJ 
C)  -73 kJ 
D)  -260 kJ 
E)  None of these choices is correct. 
A)  -18 kJ 
B)  -69 kJ 
C)  -73 kJ 
D)  -260 kJ 
E)  None of these choices is correct.

Question 3

The highly exothermic thermite reaction, in which aluminum reduces iron(III) oxide to elemental iron, has been used by railroad repair crews to weld rails together.   What mass of iron is formed when 725 kJ of heat are released?

Accepted Answer

A)  47 g 
B)  65 g 
C)  95 g 
D)  112 g 
E)  130 g 
A)  47 g 
B)  65 g 
C)  95 g 
D)  112 g 
E)  130 g

Question 4

Calculate the $\Delta$H$\degree$rxn for the following reaction. ($\Delta$H$\degree$f [AsH3(g)] = 66.4 kJ/mol; $\Delta$H$\degree$f [H3AsO4(aq)] = -904.6 kJ/mol; $\Delta$H$\degree$f [H2O(l)] = -285.8 kJ/mol)

Accepted Answer

A)  -1981.4 kJ 
B)  -685.2 kJ 
C)  -172.2 kJ 
D)  172.2 kJ 
E)  685.2 kJ 
A)  -1981.4 kJ 
B)  -685.2 kJ 
C)  -172.2 kJ 
D)  172.2 kJ 
E)  685.2 kJ

Question 5

Different chemical bonds have different potential energies.

Accepted Answer

A) True 
 B)False

Question 6

Which one of the following is a correct formation reaction?

Accepted Answer

A)  C(diamond) $\rightarrow$C(graphite) 
B)  H2(g) + O(g) $\rightarrow$ H2O(l) 
C)  C(graphite) + 4H(g) $\rightarrow$CH4(g) 
D)  6C(graphite) + 6H2O(s) $\rightarrow$C6H12O6(s) 
E)  2C(graphite) + 3H2(g) + ½O2(g) $\rightarrow$C2H5OH(l) 
A)  C(diamond) $\rightarrow$C(graphite) 
B)  H2(g) + O(g) $\rightarrow$ H2O(l) 
C)  C(graphite) + 4H(g) $\rightarrow$CH4(g) 
D)  6C(graphite) + 6H2O(s) $\rightarrow$C6H12O6(s) 
E)  2C(graphite) + 3H2(g) + ½O2(g) $\rightarrow$C2H5OH(l)

Question 7

Use Hess's Law to calculate the enthalpy change for the reaction $$
\mathrm{WO}_{3}(s)+3 \mathrm{H}_{2}(g) \rightarrow W(s)+3 \mathrm{H}_{2} \mathrm{O}(g)
$$
from the following data:
$$
\begin{array}{l}
2 \mathrm{~W}(\mathrm{~s})+3 \mathrm{O}_{2}(g) \rightarrow 2 \mathrm{WO}_{3}(\mathrm{~s}), \Delta \mathrm{H}=-1685.4 \mathrm{~kJ} \
2 \mathrm{H}_{2}(g)+\mathrm{O}_{2}(g) \rightarrow 2 \mathrm{H}_{2} \mathrm{O}(g), \Delta H=-477.84 \mathrm{~kJ}
\end{array}
$$

Accepted Answer

A)  125.9 kJ 
B)  252.9 kJ 
C)  364.9 kJ 
D)  1207.6 kJ 
E)  None of these choices is correct. 
A)  125.9 kJ 
B)  252.9 kJ 
C)  364.9 kJ 
D)  1207.6 kJ 
E)  None of these choices is correct.

Question 8

In an endothermic reaction, in going from the reactants to the products at the same temperature, the value of q is negative.

Accepted Answer

A) True 
 B)False

Question 9

Which one of the following is not a correct formation reaction? (products are correct)

Accepted Answer

A)  $ \mathrm{H}_{2}(g)+\mathrm{O}(g) \rightarrow \mathrm{H}_{2} \mathrm{O}(\mathrm{g}) $ 
B)  $ 1 / 2 \mathrm{H}_{2}(g)+1 / 2 \mathrm{Cl}_{2}(g) \rightarrow \mathrm{HCl}(g) $ 
C)  $ 6 \mathrm{C} $ (graphite) $ +3 \mathrm{H}_{2}(g) \rightarrow \mathrm{C}_{6} \mathrm{H}_{6}(l) $ 
D)  $ C $ (graphite $ ) \rightarrow C( $ diamond) 
E)  $ 6 \mathrm{C}( $graphite$ )+6 \mathrm{H}_{2}(g)+3 \mathrm{O}_{2}(g) \rightarrow \mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}(\mathrm{~s}) $ 
A)  $ \mathrm{H}_{2}(g)+\mathrm{O}(g) \rightarrow \mathrm{H}_{2} \mathrm{O}(\mathrm{g}) $ 
B)  $ 1 / 2 \mathrm{H}_{2}(g)+1 / 2 \mathrm{Cl}_{2}(g) \rightarrow \mathrm{HCl}(g) $ 
C)  $ 6 \mathrm{C} $ (graphite) $ +3 \mathrm{H}_{2}(g) \rightarrow \mathrm{C}_{6} \mathrm{H}_{6}(l) $ 
D)  $ C $ (graphite $ ) \rightarrow C( $ diamond) 
E)  $ 6 \mathrm{C}( $graphite$ )+6 \mathrm{H}_{2}(g)+3 \mathrm{O}_{2}(g) \rightarrow \mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}(\mathrm{~s}) $

Question 10

The only way in which a system can do work on the surroundings is by expansion against the external pressure.

Accepted Answer

A) True 
 B)False

Question 11

Stoichiometric amounts of nitrogen gas and hydrogen gas react in a calorimeter to produce 5.00 g of ammonia gas. The calorimeter temperature rises 0.42$\degree$C. The calorimeter and water have a combined heat capacity of 32.16 kJ/K. Calculate the heat of formation of ammonia, $\Delta$Hf$\degree$, in kJ/mol. The formation reaction for ammonia is:

Accepted Answer

A)  -46 kJ/mol 
B)  -13.5 kJ/mol 
C)  -3.97 kJ/mol 
D)  3.97 kJ/mol 
E)  13.5 kJ/mol 
A)  -46 kJ/mol 
B)  -13.5 kJ/mol 
C)  -3.97 kJ/mol 
D)  3.97 kJ/mol 
E)  13.5 kJ/mol

Question 12

The compound carbon suboxide, C3O2, is a gas at room temperature. Use the data supplied to calculate the heat of formation of carbon suboxide. (Data:  $\Delta$H$\degree$ = 127.3 kJ/mol and $\Delta$H$\degree$f of CO(g) = -110.5 kJ/mol)

Accepted Answer

A)  116.8 
B)  -93.7 
C)  227.8 
D)  -348.3 
E)  93.7 
A)  116.8 
B)  -93.7 
C)  227.8 
D)  -348.3 
E)  93.7

Question 13

A system that does no work but which transfers heat to the surroundings has:

Accepted Answer

A) q 0 B) q 0, $\Delta$E > 0 D) q > 0, $\Delta$E < 0 E) q < 0, $\Delta$E = 0 A) q 0 B) q 0, $\Delta$E > 0 D) q > 0, $\Delta$E < 0 E) q < 0, $\Delta$E = 0

Question 14

Natural gas, or methane, is an important fuel. Combustion of one mole of methane releases 802.3 kilojoules of energy. How much energy does that represent in kilocalories?

Accepted Answer

A)  1.92 *10¯1 kcal 
B)  1.92 * 102 kcal 
C)  3.36 * 103 kcal 
D)  1.92 *105 kcal 
E)  3.36 * 106 kcal 
A)  1.92 *10¯1 kcal 
B)  1.92 * 102 kcal 
C)  3.36 * 103 kcal 
D)  1.92 *105 kcal 
E)  3.36 * 106 kcal

Question 15

15.0 g of ice cubes at 0.0$\degree$C are combined with 150. g of liquid water at 70.0$\degree$C in a coffee cup calorimeter. Calculate the final temperature reached, assuming no heat loss or gain from the surroundings. (Data: specific heat capacity of H2O(l), c = 4.18 J/g*$\degree$C; H2O(s) $\rightarrow$ H2O(l) $\Delta$H = 6.02 kJ/mol)

Accepted Answer

A)  0.0 
B)  10.6 
C)  30.7 
D)  43.2 
E)  56.4 
A)  0.0 
B)  10.6 
C)  30.7 
D)  43.2 
E)  56.4

Question 16

Use the following data to calculate the standard heat (enthalpy) of formation, $\Delta$Hf, of manganese(IV) oxide, MnO2 (s).

Accepted Answer

A)  -504 kJ 
B)  -372 kJ 
C)  -24 kJ 
D)  24 kJ 
E)  504 kJ 
A)  -504 kJ 
B)  -372 kJ 
C)  -24 kJ 
D)  24 kJ 
E)  504 kJ

Question 17

In a reaction with high energy reactants and low energy products, q is negative.

Accepted Answer

A) True 
 B)False

Question 18

In a phase change of water between the liquid and the gas phases, 770.1 kJ of energy was released by the system. What was the product, and how much of it was formed in the phase change? (Data: H2O(l) $\rightarrow$ H2O(g) $\Delta$H = 44.01 kJ/mol.)

Accepted Answer

A)  315 g water vapor was produced. 
B)  17.5 g of water vapor was produced. 
C)  17.5 mol of water vapor was produced. 
D)  17.5 mol of liquid water was produced. 
E)  17.5 g of liquid water was produced. 
A)  315 g water vapor was produced. 
B)  17.5 g of water vapor was produced. 
C)  17.5 mol of water vapor was produced. 
D)  17.5 mol of liquid water was produced. 
E)  17.5 g of liquid water was produced.

Question 19

Ethanol, C2H5OH, is being promoted as a clean fuel and is used as an additive in many gasoline mixtures. Calculate the $\Delta$H$\degree$rxn for the combustion of ethanol. ($\Delta$H$\degree$f [C2H5OH(l)] = -277.7 kJ/mol; $\Delta$H$\degree$f [CO2(g)] = -393.5 kJ/mol; $\Delta$H$\degree$f [H2O(g)] = -241.8 kJ/mol)

Accepted Answer

A)  -1234.7 kJ 
B)  -751.1 kJ 
C)  -357.6 kJ 
D)  357.6 kJ 
E)  1234.7 kJ 
A)  -1234.7 kJ 
B)  -751.1 kJ 
C)  -357.6 kJ 
D)  357.6 kJ 
E)  1234.7 kJ

Which one of the following relationships is always correct?

Calcium hydroxide, which reacts with carbon dioxide to form calcium carbonate, was used by the ancient Romans as mortar in stone structures. The reaction for this process is: What is the enthalpy change if 3.8 mol of calcium carbonate is formed?

The highly exothermic thermite reaction, in which aluminum reduces iron(III) oxide to elemental iron, has been used by railroad repair crews to weld rails together. What mass of iron is formed when 725 kJ of heat are released?

Different chemical bonds have different potential energies.

Which one of the following is a correct formation reaction?

Use Hess's Law to calculate the enthalpy change for the reaction $\mathrm{WO}_{3}(s)+3 \mathrm{H}_{2}(g) \rightarrow W(s)+3 \mathrm{H}_{2} \mathrm{O}(g)$ from the following data: 2()+3(g)\rightarrow2(),\Delta=-1685.4 2(g)+(g)\rightarrow2(g),\DeltaH=-477.84

In an endothermic reaction, in going from the reactants to the products at the same temperature, the value of q is negative.

Which one of the following is not a correct formation reaction? (products are correct)

The only way in which a system can do work on the surroundings is by expansion against the external pressure.

A system that does no work but which transfers heat to the surroundings has:

Natural gas, or methane, is an important fuel. Combustion of one mole of methane releases 802.3 kilojoules of energy. How much energy does that represent in kilocalories?

Use the following data to calculate the standard heat (enthalpy) of formation, $\Delta$ H_f, of manganese(IV) oxide, MnO₂ (s). $Use the following data to calculate the standard heat (enthalpy) of formation, \Delta H<sub>f</sub>, of manganese(IV) oxide, MnO<sub>2</sub> (s).$

In a reaction with high energy reactants and low energy products, q is negative.

In a phase change of water between the liquid and the gas phases, 770.1 kJ of energy was released by the system. What was the product, and how much of it was formed in the phase change? (Data: H₂O(l) $\rightarrow$ H₂O(g) $\Delta$ H = 44.01 kJ/mol.)

Keys to the Study of Chemistry

The Components of Matter

Stoichiometry of Formulas and Equations

Three Major Classes of Chemical Reactions

Gases and the Kinetic-Molecular Theory

Quantum Theory and Atomic Structure

Electron Configuration and Chemical Periodicity

Models of Chemical Bonding

The Shapes of Molecules

Theories of Covalent Bonding

Intermolecular Forces: Liquids, Solids, and Phase Changes

The Properties of Mixtures: Solutions and Colloids

Periodic Patterns in the Main-Group Elements

Organic Compounds and the Atomic Properties of Carbon

Kinetics: Rates and Mechanisms of Chemical Reactions

Equilibrium: the Extent of Chemical Reactions

Acid-Base Equilibria

Ionic Equilibria in Aqueous Systems

Thermodynamics: Entropy, Free Energy, and the Direction of Chemical Reactions

Electrochemistry: Chemical Change and Electrical Work

The Elements in Nature and Industry

The Transition Elements and Their Coordination Compounds

Nuclear Reactions and Their Applications

Filters

Exam 6: Thermochemistry: Energy Flow and Chemical Change

Which one of the following relationships is always correct?

Calcium hydroxide, which reacts with carbon dioxide to form calcium carbonate, was used by the ancient Romans as mortar in stone structures. The reaction for this process is: What is the enthalpy change if 3.8 mol of calcium carbonate is formed?

The highly exothermic thermite reaction, in which aluminum reduces iron(III) oxide to elemental iron, has been used by railroad repair crews to weld rails together. What mass of iron is formed when 725 kJ of heat are released?

Calculate the Δ\DeltaΔ H °\degree° rxn for the following reaction. ( Δ\DeltaΔ H °\degree° f [AsH3(g)] = 66.4 kJ/mol; Δ\DeltaΔ H °\degree° f [H3AsO4(aq)] = -904.6 kJ/mol; Δ\DeltaΔ H °\degree° f [H2O(l)] = -285.8 kJ/mol)

Different chemical bonds have different potential energies.

Which one of the following is a correct formation reaction?

In an endothermic reaction, in going from the reactants to the products at the same temperature, the value of q is negative.

Which one of the following is not a correct formation reaction? (products are correct)

The only way in which a system can do work on the surroundings is by expansion against the external pressure.

The compound carbon suboxide, C3O2, is a gas at room temperature. Use the data supplied to calculate the heat of formation of carbon suboxide. (Data: Δ\DeltaΔ H °\degree° = 127.3 kJ/mol and Δ\DeltaΔ H °\degree° f of CO(g) = -110.5 kJ/mol)

A system that does no work but which transfers heat to the surroundings has:

Natural gas, or methane, is an important fuel. Combustion of one mole of methane releases 802.3 kilojoules of energy. How much energy does that represent in kilocalories?

Use the following data to calculate the standard heat (enthalpy) of formation, Δ\DeltaΔ Hf, of manganese(IV) oxide, MnO2 (s).

In a reaction with high energy reactants and low energy products, q is negative.

In a phase change of water between the liquid and the gas phases, 770.1 kJ of energy was released by the system. What was the product, and how much of it was formed in the phase change? (Data: H2O(l) →\rightarrow→ H2O(g) Δ\DeltaΔ H = 44.01 kJ/mol.)

Keys to the Study of Chemistry

The Components of Matter

Stoichiometry of Formulas and Equations

Three Major Classes of Chemical Reactions

Gases and the Kinetic-Molecular Theory

Quantum Theory and Atomic Structure

Electron Configuration and Chemical Periodicity

Models of Chemical Bonding

The Shapes of Molecules

Theories of Covalent Bonding

Intermolecular Forces: Liquids, Solids, and Phase Changes

The Properties of Mixtures: Solutions and Colloids

Periodic Patterns in the Main-Group Elements

Organic Compounds and the Atomic Properties of Carbon

Kinetics: Rates and Mechanisms of Chemical Reactions

Equilibrium: the Extent of Chemical Reactions

Acid-Base Equilibria

Ionic Equilibria in Aqueous Systems

Thermodynamics: Entropy, Free Energy, and the Direction of Chemical Reactions

Electrochemistry: Chemical Change and Electrical Work

The Elements in Nature and Industry

The Transition Elements and Their Coordination Compounds

Nuclear Reactions and Their Applications

Filters

Use the following data to calculate the standard heat (enthalpy) of formation, $\Delta$ H_f, of manganese(IV) oxide, MnO₂ (s). $Use the following data to calculate the standard heat (enthalpy) of formation, \Delta H<sub>f</sub>, of manganese(IV) oxide, MnO<sub>2</sub> (s).$

In a phase change of water between the liquid and the gas phases, 770.1 kJ of energy was released by the system. What was the product, and how much of it was formed in the phase change? (Data: H₂O(l) $\rightarrow$ H₂O(g) $\Delta$ H = 44.01 kJ/mol.)