Q: Which of the following best explains why ice melts spontaneously above 0°C?

The process is endothermic but the increase in entropy makes $\Delta G$ negative.

Q: According to the Second Law of Thermodynamics, which statement is correct?

The total entropy of the universe increases in any spontaneous reaction.

Q: Which equation relates the entropy change of the surroundings ($\Delta S_{surr}$) to the enthalpy change of the system ($\Delta H_{sys}$) at constant temperature?

$\Delta S_{surr} = -\frac{\Delta H_{sys}}{T}$

Q: Which of the following processes will result in a decrease in entropy at constant temperature?

Condensation of water vapor to liquid water

Q: Which statement about microstates and entropy is correct?

A macrostate with more microstates has higher entropy.

Q: Which of the following is true about the Third Law of Thermodynamics?

The entropy of a perfect crystal at absolute zero is zero.

Question 1

Which of the following statements best describes the First Law of Thermodynamics?

Accepted Answer

Energy cannot be created or destroyed; it can only be converted from one form to another.

Question 2

A chemical reaction occurs in a sealed container at constant volume. Which equation correctly relates the change in internal energy ($\Delta E$) to heat ($q$) and work ($w$)?

Accepted Answer

$\Delta E = q + w$

Question 3

Which process is associated with an increase in entropy ($S$) at constant temperature?

Accepted Answer

Melting of ice to liquid water

Question 4

For the reaction $\mathrm{CH_4(g) + 2O_2(g) \rightarrow CO_2(g) + 2H_2O(l)}$, which statement is true?

Accepted Answer

The reaction is exothermic and decreases entropy in the system.

Question 5

Which equation defines the change in entropy ($\Delta S$) for a system at constant temperature?

Accepted Answer

$\Delta S = \frac{q_{sys}}{T}$

Question 6

Which of the following molecules would have the highest standard molar entropy ($S^\circ$)?

Accepted Answer

A linear hydrocarbon with 8 carbon atoms

Question 7

What is the correct expression for Gibbs Free Energy ($\Delta G$)?

Accepted Answer

$\Delta G = \Delta H - T\Delta S$

Question 8

A process is spontaneous if:

Accepted Answer

$\Delta G < 0$

Question 9

Which of the following best explains why ice melts spontaneously above 0°C?

Accepted Answer

The process is endothermic but the increase in entropy makes $\Delta G$ negative.

Question 10

According to the Second Law of Thermodynamics, which statement is correct?

Accepted Answer

The total entropy of the universe increases in any spontaneous reaction.

Question 11

Which equation relates the entropy change of the surroundings ($\Delta S_{surr}$) to the enthalpy change of the system ($\Delta H_{sys}$) at constant temperature?

Accepted Answer

$\Delta S_{surr} = -\frac{\Delta H_{sys}}{T}$

Question 12

Which of the following processes will result in a decrease in entropy at constant temperature?

Accepted Answer

Condensation of water vapor to liquid water

Question 13

Which statement about microstates and entropy is correct?

Accepted Answer

A macrostate with more microstates has higher entropy.

Question 14

Which of the following is true about the Third Law of Thermodynamics?

Accepted Answer

The entropy of a perfect crystal at absolute zero is zero.

Question 15

Which of the following would increase the entropy of a system?

Accepted Answer

Increasing the volume

Question 16

For the reaction $\mathrm{NH_3(g) + HCl(g) \rightarrow NH_4Cl(s)}$, what happens to the entropy of the system?

Accepted Answer

Entropy decreases because two gas molecules form one solid molecule.

Question 17

Which of the following is a correct statement about enthalpy of fusion ($\Delta H_{fusion}$)?

Accepted Answer

It is the amount of heat necessary to melt a substance without changing its temperature.

Question 18

Which equation is used to calculate the standard entropy change for a reaction ($\Delta S^\circ_{rxn}$)?

Accepted Answer

$\Delta S^\circ_{rxn} = \sum n_{products} S^\circ_{products} - \sum n_{reactants} S^\circ_{reactants}$

Question 19

Which of the following best describes a spontaneous process?

Accepted Answer

A process that proceeds without outside intervention, but may require an initial energy boost.

Chapter 18: Free Energy and Thermodynamics – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards