Question 1

Thermal energy is

Accepted Answer

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.

Question 2

At 25°C, the following heats of reaction are known:   
At the same temperature, use Hess's law to calculate$\Delta$H°rxn for the reaction: ClF(g)+ F2(g)$\rarr$ClF3(g)

Accepted Answer

A) -217.5 kJ/mol 
B) -130.2 kJ/mol 
C) 217.5 kJ/mol 
D) -108.7 kJ/mol 
E) 465.4 kJ/mol 
A) -217.5 kJ/mol 
B) -130.2 kJ/mol 
C) 217.5 kJ/mol 
D) -108.7 kJ/mol 
E) 465.4 kJ/mol

Question 3

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

Accepted Answer

A) N2(g)+ 3H2(g)$\rarr$2NH3(g) 
B) 4PH3(g)$\rarr$P4(g)+ 6H2(g) 
C) H2(g)+ Cl2(g)$\rarr$ 2HCl(g) 
D) CO2(g)+ 2H2O(l)$\rarr$CH4(g)+ 2O2(g) 
E) P4(s)+ 10Cl2(g)$\rarr$4PCl5(s) 
A) N2(g)+ 3H2(g)$\rarr$2NH3(g) 
B) 4PH3(g)$\rarr$P4(g)+ 6H2(g) 
C) H2(g)+ Cl2(g)$\rarr$ 2HCl(g) 
D) CO2(g)+ 2H2O(l)$\rarr$CH4(g)+ 2O2(g) 
E) P4(s)+ 10Cl2(g)$\rarr$4PCl5(s)

Question 4

Define specific heat.

Accepted Answer

The amount of heat required to

Question 5

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

Accepted Answer

A) 2H2O2(l)$\rarr$ 2H2O(l)+ O2(g) 
B) CaCO3(s)$\rarr$CaO(s)+CO2(g) 
C) NO(g)+ O3(g)$\rarr$NO2(g)+ O2(g) 
D) 2C2H6(g)+ 7O2(g)$\rarr$4CO2(g)+ 6H2O(l) 
E) 4NH3(g)+ 5O2(g)$\rarr$ 4NO(g)+ 6H2O(g) 
A) 2H2O2(l)$\rarr$ 2H2O(l)+ O2(g) 
B) CaCO3(s)$\rarr$CaO(s)+CO2(g) 
C) NO(g)+ O3(g)$\rarr$NO2(g)+ O2(g) 
D) 2C2H6(g)+ 7O2(g)$\rarr$4CO2(g)+ 6H2O(l) 
E) 4NH3(g)+ 5O2(g)$\rarr$ 4NO(g)+ 6H2O(g)

Question 6

Find $\Delta$H°rxn for the reaction
2Na(s)+ 2H2O(l)$\rarr$ 2NaOH(aq)+ 2H2(g).
[$\Delta$H°f (NaOH(aq))= -426.8 kJ/mol; $\Delta$H°f (H2O(l))= -285.5 kJ/mol]

Accepted Answer

The answer of Find $\Delta$H°rxn for the reaction
2Na(s)+ 2H2O(l)$\rarr$ 2NaOH(aq)+...

Question 7

Calculate the amount of heat necessary to raise the temperature of 12.0 g of water from 15.4°C to 93.0°C.The specific heat of water = 4.18 J/g·°C.

Accepted Answer

A) 0.027 J 
B) 324 J 
C) 389 J 
D) 931 J 
E) 3,890 J 
A) 0.027 J 
B) 324 J 
C) 389 J 
D) 931 J 
E) 3,890 J

Question 8

To which one of the following reactions occurring at 25°C does the symbol $\Delta$H°f[HNO3(l)] refer?

Accepted Answer

A) H(g)+ N(g)+ O3(g)$\rarr$  HNO3(l) 
B) (1/2)H2(g)+ (1/2)N2(g)+ (3/2)O2(g)$\rarr$  HNO3(l) 
C) HNO3(l)$\rarr$  (1/2)H2(g)+ (1/2)N2(g)+ (3/2)O2(g) 
D) HNO3(l)$\rarr$  H(g)+ N(g)+ 3O(g) 
E) H2(g)+ N2(g)+ O3(g)$\rarr$ HNO3(l) 
A) H(g)+ N(g)+ O3(g)$\rarr$  HNO3(l) 
B) (1/2)H2(g)+ (1/2)N2(g)+ (3/2)O2(g)$\rarr$  HNO3(l) 
C) HNO3(l)$\rarr$  (1/2)H2(g)+ (1/2)N2(g)+ (3/2)O2(g) 
D) HNO3(l)$\rarr$  H(g)+ N(g)+ 3O(g) 
E) H2(g)+ N2(g)+ O3(g)$\rarr$ HNO3(l)

Question 9

The heat released when one mole of water is formed from the elements is 1,198 kJ. An experiment was conducted that permitted water to form in this manner, and the heat was contained in 2.0 liters of water.The water temperature before the reaction was 34.5°C, and after the reaction it had risen to 52.0°C. How many moles of water were formed? (The specific heat of water is 4.184 J/g·°C.)

Accepted Answer

The answer of The heat released when one mole of...

Question 10

For the reaction   how many grams of C(graphite)must be burned to release 275 kJ of heat?

Accepted Answer

A) 22.3 g 
B) 0.70 g 
C) 12.0 g 
D) 17.1 g 
E) 8.40 g 
A) 22.3 g 
B) 0.70 g 
C) 12.0 g 
D) 17.1 g 
E) 8.40 g

Question 11

Calculate the standard enthalpy of formation of liquid methanol, CH3OH(l), using the following information:

Accepted Answer

A) -1,691.5 kJ/mol 
B) -238.7 kJ/mol 
C) 1691.5 kJ/mol 
D) 47.1 kJ/mol 
E) -47.1 kJ/mol 
A) -1,691.5 kJ/mol 
B) -238.7 kJ/mol 
C) 1691.5 kJ/mol 
D) 47.1 kJ/mol 
E) -47.1 kJ/mol

Question 12

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?

Accepted Answer

Question 13

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.

Accepted Answer

A) 7.6 * 103 kJ 
B) 2.8 * 102 kJ 
C) 1.4 * 102 kJ 
D) 5.6 * 102 kJ 
E) 2.5 * 103 kJ 
A) 7.6 * 103 kJ 
B) 2.8 * 102 kJ 
C) 1.4 * 102 kJ 
D) 5.6 * 102 kJ 
E) 2.5 * 103 kJ

Question 14

The heat capacity of 20.0 g of water is 83.7 J/°C.

Accepted Answer

A) True 
 B)False

Question 15

Given the thermochemical equation 2SO2(g)+ O2(g)$\rarr$2SO3(g), $\Delta$H°rxn= -198 kJ/mol, how much heat is evolved when 600.g of SO2 is burned?

Accepted Answer

A) 5.46 * 10-2 kJ 
B) 928 kJ 
C) 1.85 * 103 kJ 
D) 59,400 kJ 
E) 3.71 * 103 kJ 
A) 5.46 * 10-2 kJ 
B) 928 kJ 
C) 1.85 * 103 kJ 
D) 59,400 kJ 
E) 3.71 * 103 kJ

Question 16

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?

Accepted Answer

Question 17

The heat absorbed by a system at constant pressure is equal to $\Delta$E + P$\Delta$V.

Accepted Answer

A) True 
 B)False

Question 18

A glass containing 200.g of H2O at 20°C was placed in a refrigerator. The water loses 11.7 kJ as it cools to a constant temperature. What is its new temperature? The specific heat of water is 4.184 J/g·°C.

Accepted Answer

A) 0.013°C 
B) 4°C 
C) 6°C 
D) 14°C 
E) 34°C 
A) 0.013°C 
B) 4°C 
C) 6°C 
D) 14°C 
E) 34°C

Question 19

Chemical reactions in a bomb calorimeter occur at constant pressure.

Accepted Answer

A) True 
 B)False

Question 20

A 100.mL sample of 0.200 M aqueous hydrochloric acid is added to 100.mL of 0.200 M aqueous ammonia in a calorimeter whose heat capacity (excluding any water)is 480.J/K. The following reaction occurs when the two solutions are mixed. HCl(aq)+ NH3(aq)$\rarr$ NH4Cl(aq)
The temperature increase is 2.34°C. Calculate $\Delta$H per mole of HCl and NH3 reacted.

Accepted Answer

A) 154 kJ/mol 
B) 1.96 kJ/mol 
C) 485 kJ/mol 
D) -1.96 kJ/mol 
E) -154 kJ/mol 
A) 154 kJ/mol 
B) 1.96 kJ/mol 
C) 485 kJ/mol 
D) -1.96 kJ/mol 
E) -154 kJ/mol

Exam 6: Thermo-Chemistry

Thermal energy is

At 25°C, the following heats of reaction are known: At the same temperature, use Hess's law to calculate Δ\DeltaΔ H°rxn for the reaction: ClF(g)+ F2(g) →\rarr→ ClF3(g)

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

Define specific heat.

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

Find Δ\DeltaΔ H°rxn for the reaction 2Na(s)+ 2H2O(l) →\rarr→ 2NaOH(aq)+ 2H2(g). [ Δ\DeltaΔ H°f (NaOH(aq))= -426.8 kJ/mol; Δ\DeltaΔ H°f (H2O(l))= -285.5 kJ/mol]

Calculate the amount of heat necessary to raise the temperature of 12.0 g of water from 15.4°C to 93.0°C.The specific heat of water = 4.18 J/g·°C.

To which one of the following reactions occurring at 25°C does the symbol Δ\DeltaΔ H°f[HNO3(l)] refer?

For the reaction how many grams of C(graphite)must be burned to release 275 kJ of heat?

Calculate the standard enthalpy of formation of liquid methanol, CH3OH(l), using the following information:

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.

The heat capacity of 20.0 g of water is 83.7 J/°C.

Given the thermochemical equation 2SO2(g)+ O2(g) →\rarr→ 2SO3(g), Δ\DeltaΔ H°rxn= -198 kJ/mol, how much heat is evolved when 600.g of SO2 is burned?

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 absorbed by a system at constant pressure is equal to Δ\DeltaΔ E + P Δ\DeltaΔ V.

A glass containing 200.g of H2O at 20°C was placed in a refrigerator. The water loses 11.7 kJ as it cools to a constant temperature. What is its new temperature? The specific heat of water is 4.184 J/g·°C.

Chemical reactions in a bomb calorimeter occur at constant pressure.

Chemistry: The Study of Change

Atoms, Molecules, and Ions

Mass Relationships in Chemical Reactions

Reactions in Aqueous Solution

Gases

Quantum Theory and the Electronic Structure of Atoms

Periodic Relationships Among the Elements

Chemical Bonding I: Basic Concepts

Chemical Bonding Ii: Molecular Geometry and Hybridization of Atomic Orbitals

Intermolecular Forces and Liquids and Solids

Physical Properties of Solutions

Chemical Kinetics

Chemical Equilibrium

Acids and Bases

Acid-Base Equilibria and Solubility Equilibria

Chemistry in the Atmosphere

Entropy, Free Energy, and Equilibrium

Electrochemistry

Metallurgy and the Chemistry of Metals

Nonmetallic Elements and Their Compounds

Transition Metal Chemistry and Coordination Compounds

Nuclear Chemistry

Organic Chemistry

Synthetic and Natural Organic Polymers

Filters

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

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

Find $\Delta$ H°_rxn for the reaction 2Na(s)+ 2H₂O(l) $\rarr$ 2NaOH(aq)+ 2H₂(g). [ $\Delta$ H°_f (NaOH(aq))= -426.8 kJ/mol; $\Delta$ H°_f (H₂O(l))= -285.5 kJ/mol]

To which one of the following reactions occurring at 25°C does the symbol $\Delta$ H°_f[HNO₃(l)] refer?

Calculate the standard enthalpy of formation of liquid methanol, CH₃OH(l), using the following information:

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.

Given the thermochemical equation 2SO₂(g)+ O₂(g) $\rarr$ 2SO₃(g), $\Delta$ H°_rxn= -198 kJ/mol, how much heat is evolved when 600.g of SO₂ is burned?

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 absorbed by a system at constant pressure is equal to $\Delta$ E + P $\Delta$ V.

A glass containing 200.g of H₂O at 20°C was placed in a refrigerator. The water loses 11.7 kJ as it cools to a constant temperature. What is its new temperature? The specific heat of water is 4.184 J/g·°C.