Question 1

For which of the following reactions is D H - D E > 0?

Accepted Answer

The reaction is endothermic, meaning that it requires energy to proceed. The enthalpy change for the reaction is positive, indicating that the products have more energy than the reactants.

Question 2

The combustion of a 3.06 g sample of formic acid (H CO₂ H(  ), molar mass = 46.03 g/mol) in a bomb calorimeter with a heat capacity of 5.423 J/ C causes the temperature to rise from 23.27 C to 26.41 C. What is D E for the reaction?
2 H CO₂ H (  ) + O₂(g) 2 CO₂ (g) + 2 H₂ O (  )

Accepted Answer

D

Question 3

From the D E given for 25 ° C, calculate D H at the same temperature for the reaction: 2 N₂O (g)→2 N₂ (g) + O₂ (g) D E = - 161.62 kJ

Accepted Answer

C

Question 4

Which of the following units express(es) a quantity of energy?
I. joule
II. L × atm
III. kcal

Accepted Answer

All three units express quantities of energy: joule is the SI unit of energy, L × atm is used in thermodynamics (especially in the context of gases), and kcal (kilocalories) is commonly used in food energy.

Question 5

When a sample of an ideal gas is compressed at 25 ° C from 39.0 L to 15.0 L at a constant pressure of 1.90 atm, the work is

Accepted Answer

The answer of When a sample of an ideal gas...

Question 6

Which of the following statements is incorrect ?

Accepted Answer

Heat absorbed by a system is not a state function as it depends on the process or path taken to reach the final state.

Question 7

Which of the following systems show(s) a decrease in entropy?
The system is underlined.

Accepted Answer

A) When molten iron solidifies, it goes from a liquid to a solid state, which means its particles are becoming more ordered. This represents a decrease in entropy. C) Solving a jigsaw puzzle involves organizing scattered pieces into a specific, ordered arrangement, which also represents a decrease in entropy.

Question 8

A sample of an ideal gas at 275 K occupies a volume oF₄2 L. The sample contracts to a volume of 15 L at a constant pressure of 1.50 atm, while heat of 2400 J is lost to the surroundings. What is D E for this process?

Accepted Answer

The answer of A sample of an ideal gas at...

Question 9

The mathematical form of the first law of thermodynamics is:

Accepted Answer

The first law of thermodynamics states that energy cannot be created or destroyed, only transferred or converted from one form to another. The mathematical expression of this law is dE = q + w, where dE is the change in internal energy of a system, q is the heat added to the system, and w is the work done by or on the system. Therefore, option B is the correct choice.

Question 10

One mole of an ideal gas at 300 K expands from 2.0 L to 9.0 L against a constant external pressure of 1.8 atm. The work done by this expansion is (in L × atm):

Accepted Answer

The answer of One mole of an ideal gas at...

Question 11

From the D E given for 25 ° C, calculate D H at the same temperature for the reaction: 2 HI (g)→H₂ (g) + I₂ (g) D E = +9.48 kJ

Accepted Answer

The enthalpy change, DH, is related to the internal energy change, DE, by the equation DH = DE + RTΔn, where R is the gas constant, T is the temperature in Kelvin, and Δn is the change in moles of gas between reactants and products. In this case, Δn = (2 moles of gas in products) - (1 mole of gas in reactants) = 1, since we count the stoichiometric coefficients as the number of moles.

Plugging in the given values, we get DH = +9.48 kJ + (8.314 J/(mol·K))(298 K)(1) / 1000 J/kJ = +9.80 kJ.

However, we need to round our final answer to two significant figures, since that's the precision of the given DE value. The closest choice is B, +9.48 kJ, which is the same as the given DE value. Therefore, B is the best choice.

Question 12

Which thermodynamic parameter listed below measures the degree of disorder associated with a system?

Accepted Answer

Entropy is a thermodynamic parameter that measures the degree of disorder or randomness associated with a system. It is represented by the symbol S and is a state function.

Question 13

Which substance listed below would be expected to have the greatest entropy value, S ° ?
Assume all substances are in the gas phase at the same temperature.

Accepted Answer

Pentane has the greatest number of carbon atoms and therefore has the most complex molecular structure. This increased complexity leads to more possible arrangements of molecules and thus a higher entropy value.

Question 14

If only work of expansion is done, the heat, q , for a change at constant temperature and volume is equal to what?

Accepted Answer

The heat, q, for a change at constant temperature and volume is equal to the work of expansion, w.

Question 15

When a 3.125 g sample of ammonium nitrate (NH ₄NO₃ , molar mass = 80.05 g/mol) decomposes in a bomb calorimeter with a heat capacity oF₄.116 kJ/ C, the temperature rises from 24.15 C to 25.35 C. What is D E for the decomposition of ammonium nitrate? NH ₄NO₃(s) N₂O (g) + 2 H₂ O ( )

Accepted Answer

The answer of When a 3.125 g sample of ammonium...

Question 16

The combustion of a 0.440 g sample of ethanol (C₂ H₅ OH, molar mass = 46.07 g/mol) in a bomb calorimeter with a heat capacity of 5.278 kJ/ C causes the temperature to rise from 23.98 C to 26.45 C. What is D E for the reaction? C₂ H₅ OH ( ) + 3 O₂(g) 2 CO₂ (g) + 3 H₂ O ( )

Accepted Answer

The answer of The combustion of a 0.440 g sample...

Question 17

Which one of the following systems shows a positive entropy change?
The system is underlined.

Accepted Answer

Ice melting shows a positive entropy change because the solid ice has low entropy due to its ordered crystalline structure. When it melts, the particles become more disordered, resulting in an increase in entropy.

Question 18

If q of the system is negative:

Accepted Answer

When q of the system is negative, it means the system is releasing heat to the surroundings, thus heating them.

Question 19

One mole of a gas, initially at 300 K and 1.00 atm, undergoes a change so the final conditions are T = 400 K and V = 50.0 liters. Which of the following cannot be calculated from this information?

Accepted Answer

We are not given any information about the process undergone by the gas, so we cannot determine the heat transferred between the system and the surroundings (q). The change in volume (D V), change in pressure (D P), and change in temperature (D T) can all be calculated using the initial and final values given.

Question 20

Calculate the work done by 1.00 mol of an ideal gas when it expands from a volume of 14.00 L to a volume of 18.00 L against a constant external pressure of 2.00 atm.

Accepted Answer

The work done by the gas during expansion against a constant external pressure can be calculated using the formula $w = -P_{\text{ext}}\Delta V$, where $P_{\text{ext}}$ is the external pressure and $\Delta V$ is the change in volume. Here, $\Delta V = 18.00\,L - 14.00\,L = 4.00\,L$ and $P_{\text{ext}} = 2.00\,atm$, so $w = -2.00\,atm \times 4.00\,L = -8.00\,L \times atm$.

Quiz 17: Chemical Thermodynamics

For which of the following reactions is D H - D E > 0?

The combustion of a 3.06 g sample of formic acid (H CO₂ H( ) , molar mass = 46.03 g/mol) in a bomb calorimeter with a heat capacity of 5.423 J/ C causes the temperature to rise from 23.27 C to 26.41 C. What is D E for the reaction? 2 H CO₂ H ( ) + O₂(g) 2 CO₂ (g) + 2 H₂ O ( )

From the D E given for 25 ° C, calculate D H at the same temperature for the reaction: 2 N₂O (g) →2 N₂ (g) + O₂ (g) D E = - 161.62 kJ

Which of the following units express(es) a quantity of energy? I. joule II. L × atm III. kcal

When a sample of an ideal gas is compressed at 25 ° C from 39.0 L to 15.0 L at a constant pressure of 1.90 atm, the work is

Which of the following statements is incorrect ?

Which of the following systems show(s) a decrease in entropy? The system is underlined.

A sample of an ideal gas at 275 K occupies a volume oF₄2 L. The sample contracts to a volume of 15 L at a constant pressure of 1.50 atm, while heat of 2400 J is lost to the surroundings. What is D E for this process?

The mathematical form of the first law of thermodynamics is:

One mole of an ideal gas at 300 K expands from 2.0 L to 9.0 L against a constant external pressure of 1.8 atm. The work done by this expansion is (in L × atm) :

From the D E given for 25 ° C, calculate D H at the same temperature for the reaction: 2 HI (g) →H₂ (g) + I₂ (g) D E = +9.48 kJ

Which thermodynamic parameter listed below measures the degree of disorder associated with a system?

Which substance listed below would be expected to have the greatest entropy value, S ° ? Assume all substances are in the gas phase at the same temperature.

If only work of expansion is done, the heat, q , for a change at constant temperature and volume is equal to what?

When a 3.125 g sample of ammonium nitrate (NH ₄NO₃ , molar mass = 80.05 g/mol) decomposes in a bomb calorimeter with a heat capacity oF₄.116 kJ/ C, the temperature rises from 24.15 C to 25.35 C. What is D E for the decomposition of ammonium nitrate? NH ₄NO₃(s) N₂O (g) + 2 H₂ O ( )

The combustion of a 0.440 g sample of ethanol (C₂ H₅ OH, molar mass = 46.07 g/mol) in a bomb calorimeter with a heat capacity of 5.278 kJ/ C causes the temperature to rise from 23.98 C to 26.45 C. What is D E for the reaction? C₂ H₅ OH ( ) + 3 O₂(g) 2 CO₂ (g) + 3 H₂ O ( )

Which one of the following systems shows a positive entropy change? The system is underlined.

If q of the system is negative:

One mole of a gas, initially at 300 K and 1.00 atm, undergoes a change so the final conditions are T = 400 K and V = 50.0 liters. Which of the following cannot be calculated from this information?

Calculate the work done by 1.00 mol of an ideal gas when it expands from a volume of 14.00 L to a volume of 18.00 L against a constant external pressure of 2.00 atm.

Quiz 17: Chemical Thermodynamics

For which of the following reactions is D H - D E > 0?

The combustion of a 3.06 g sample of formic acid (H CO₂ H( ) , molar mass = 46.03 g/mol) in a bomb calorimeter with a heat capacity of 5.423 J/ C causes the temperature to rise from 23.27 C to 26.41 C. What is D E for the reaction? 2 H CO₂ H ( ) + O₂(g) 2 CO₂ (g) + 2 H₂ O ( )

From the D E given for 25 ° C, calculate D H at the same temperature for the reaction: 2 N2O (g) →2 N2 (g) + O2 (g) D E = - 161.62 kJ

Which of the following units express(es) a quantity of energy? I. joule II. L × atm III. kcal

When a sample of an ideal gas is compressed at 25 ° C from 39.0 L to 15.0 L at a constant pressure of 1.90 atm, the work is

Which of the following statements is incorrect ?

Which of the following systems show(s) a decrease in entropy? The system is underlined.

A sample of an ideal gas at 275 K occupies a volume oF42 L. The sample contracts to a volume of 15 L at a constant pressure of 1.50 atm, while heat of 2400 J is lost to the surroundings. What is D E for this process?

The mathematical form of the first law of thermodynamics is:

One mole of an ideal gas at 300 K expands from 2.0 L to 9.0 L against a constant external pressure of 1.8 atm. The work done by this expansion is (in L × atm) :

From the D E given for 25 ° C, calculate D H at the same temperature for the reaction: 2 HI (g) →H2 (g) + I2 (g) D E = +9.48 kJ

Which thermodynamic parameter listed below measures the degree of disorder associated with a system?

Which substance listed below would be expected to have the greatest entropy value, S ° ? Assume all substances are in the gas phase at the same temperature.

If only work of expansion is done, the heat, q , for a change at constant temperature and volume is equal to what?

When a 3.125 g sample of ammonium nitrate (NH ₄NO3 , molar mass = 80.05 g/mol) decomposes in a bomb calorimeter with a heat capacity oF4.116 kJ/ C, the temperature rises from 24.15 C to 25.35 C. What is D E for the decomposition of ammonium nitrate? NH ₄NO3(s) N₂O (g) + 2 H₂ O ( )

The combustion of a 0.440 g sample of ethanol (C₂ H5 OH, molar mass = 46.07 g/mol) in a bomb calorimeter with a heat capacity of 5.278 kJ/ C causes the temperature to rise from 23.98 C to 26.45 C. What is D E for the reaction? C₂ H5 OH ( ) + 3 O₂(g) 2 CO₂ (g) + 3 H₂ O ( )

Which one of the following systems shows a positive entropy change? The system is underlined.

If q of the system is negative:

One mole of a gas, initially at 300 K and 1.00 atm, undergoes a change so the final conditions are T = 400 K and V = 50.0 liters. Which of the following cannot be calculated from this information?

Calculate the work done by 1.00 mol of an ideal gas when it expands from a volume of 14.00 L to a volume of 18.00 L against a constant external pressure of 2.00 atm.

From the D E given for 25 ° C, calculate D H at the same temperature for the reaction: 2 N₂O (g) →2 N₂ (g) + O₂ (g) D E = - 161.62 kJ

A sample of an ideal gas at 275 K occupies a volume oF₄2 L. The sample contracts to a volume of 15 L at a constant pressure of 1.50 atm, while heat of 2400 J is lost to the surroundings. What is D E for this process?

From the D E given for 25 ° C, calculate D H at the same temperature for the reaction: 2 HI (g) →H₂ (g) + I₂ (g) D E = +9.48 kJ

When a 3.125 g sample of ammonium nitrate (NH ₄NO₃ , molar mass = 80.05 g/mol) decomposes in a bomb calorimeter with a heat capacity oF₄.116 kJ/ C, the temperature rises from 24.15 C to 25.35 C. What is D E for the decomposition of ammonium nitrate? NH ₄NO₃(s) N₂O (g) + 2 H₂ O ( )

The combustion of a 0.440 g sample of ethanol (C₂ H₅ OH, molar mass = 46.07 g/mol) in a bomb calorimeter with a heat capacity of 5.278 kJ/ C causes the temperature to rise from 23.98 C to 26.45 C. What is D E for the reaction? C₂ H₅ OH ( ) + 3 O₂(g) 2 CO₂ (g) + 3 H₂ O ( )