Question 1

Which statement best describes the First Law of Thermodynamics?

Accepted Answer

Energy cannot be created or destroyed, only converted from one form to another.

Question 2

Which of the following processes is spontaneous at room temperature?

Accepted Answer

Ice melting into liquid water.

Question 3

Which equation represents the relationship between entropy and the number of microstates?

Accepted Answer

$$S = k \ln W$$

Question 4

According to the Second Law of Thermodynamics, what happens to the entropy of the universe during a spontaneous process?

Accepted Answer

It increases.

Question 5

Which of the following changes will increase the entropy of a system?

Accepted Answer

Increasing the number of atoms or molecules.

Question 6

Which physical state change is associated with an increase in entropy?

Accepted Answer

Solid to gas.

Question 7

What is the entropy of a pure crystalline substance at absolute zero according to the Third Law of Thermodynamics?

Accepted Answer

$$S = 0$$

Question 8

Which of the following best describes a reversible process?

Accepted Answer

A process that maximizes the work done by the system on the surroundings.

Question 9

Which equation is used to calculate the change in entropy for a chemical reaction?

Accepted Answer

$$\Delta S^\circ = \sum n S^\circ_{products} - \sum m S^\circ_{reactants}$$

Question 10

Which equation defines Gibbs Free Energy?

Accepted Answer

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

Question 11

A reaction has $$\Delta H  0. $$What can be said about its spontaneity?

Accepted Answer

It is spontaneous at all temperatures.

Question 12

If $$\Delta G$$ for a reaction is positive, what does this indicate?

Accepted Answer

The reaction is nonspontaneous in the forward direction.

Question 13

Which equation relates the standard free energy change to the equilibrium constant?

Accepted Answer

$$\Delta G^\circ = -RT \ln K$$

Question 14

In a cell, the oxidation of glucose is coupled to the synthesis of ATP. What is the role of free energy in this process?

Accepted Answer

Free energy released by glucose oxidation is used to convert ADP to ATP.

Question 15

Which molecular motion contributes most to the entropy of a gas at high temperature?

Accepted Answer

Translational motion.

Question 16

A chemical reaction has $$\Delta H \u003e 0$$ and $$\Delta S \u003c 0. $$Under what conditions is the reaction spontaneous?

Accepted Answer

Never spontaneous.

Question 17

Which factor does NOT increase the number of microstates in a system?

Accepted Answer

Decreasing the number of atoms.

Question 18

If $$Q \u003c K$$ for a reaction, what will happen according to thermodynamics?

Accepted Answer

The reaction will shift right to form products.

Question 19

Which of the following is a plausible reason why a nonspontaneous reaction can occur in nature?

Accepted Answer

It is coupled to a spontaneous reaction.

Question 20

Which statement about spontaneous processes is correct?

Accepted Answer

All spontaneous processes are irreversible.

Chapter 19: Chemical Thermodynamics – Study Notes

Study Guide - Practice Questions