Question 1

Which statement best describes the Second Law of Thermodynamics?

Accepted Answer

The entropy of the universe can never decrease; $$\Delta S_{universe} \geq 0.$$

Question 2

What is the statistical definition of entropy according to Boltzmann?

Accepted Answer

$$S = k_B \ln W$$

Question 3

If you flip a fair coin 4 times, how many possible microstates are there?

Accepted Answer

16

Question 4

Which process results in an increase in entropy?

Accepted Answer

Water evaporating

Question 5

According to the Third Law of Thermodynamics, what is the entropy of a perfect crystal at absolute zero?

Accepted Answer

$$S = 0$$

Question 6

Which of the following best explains why the universe tends toward disorder?

Accepted Answer

There are more microstates that appear disordered than ordered.

Question 7

A gas is allowed to expand in a box. What happens to the entropy of the system?

Accepted Answer

Entropy increases as the gas particles occupy more possible positions.

Question 8

Which of the following is a correct unit for entropy?

Accepted Answer

$$\mathrm{J} / \mathrm{K}$$

Question 9

Consider the melting of ice at 0°C. Which statement is true regarding entropy?

Accepted Answer

Entropy increases because the molecules become more disordered.

Question 10

Which of the following processes would have the largest positive change in entropy?

Accepted Answer

A solid subliming to a gas

Question 11

If a system has $$W = 1$$ microstate, what is its entropy?

Accepted Answer

$$S = 0$$

Question 12

Which scenario best illustrates the concept of increasing entropy in a real-world context?

Accepted Answer

Dissolving salt in water

Question 13

For a reversible process at constant temperature, how is the change in entropy ($$\Delta S) $$calculated?

Accepted Answer

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

Question 14

Which of the following statements about entropy is FALSE?

Accepted Answer

Systems with higher entropy appear more ordered.

Question 15

Which process is most likely to be spontaneous based on entropy considerations?

Accepted Answer

A gas spreading to fill a larger volume

Question 16

If the entropy change of the universe ($$\Delta S_{universe}) $$for a reaction is negative, what does this imply?

Accepted Answer

The reaction is non-spontaneous.

Question 17

Which of the following is NOT a way to increase the entropy of a system?

Accepted Answer

Freezing a liquid

Question 18

What is the entropy change when a perfect crystal is cooled from 10 K to 0 K?

Accepted Answer

Entropy decreases to zero.

Question 19

Which of the following best describes a microstate?

Accepted Answer

A specific arrangement of the components of a system at a given energy.

Question 20

Why does the probability distribution of heads in coin flipping become more sharply peaked as the number of flips increases?

Accepted Answer

The number of possible arrangements increases, but the most probable outcome becomes more dominant.

Module 4.4: Entropy and the Laws of Thermodynamics

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