$\mathrm{2\ SO_2 (g) + O_2 (g) \rightarrow 2\ SO_3 (g)}$

Condensation of water vapor to liquid

Question 1

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

Accepted Answer

It increases.

Question 2

Which of the following physical changes results in a decrease in entropy ($\Delta S < 0$)?

Accepted Answer

Freezing water to form ice

Question 3

Which chemical reaction is most likely to have a positive entropy change ($\Delta S > 0$)?

Accepted Answer

$\mathrm{CaCO_3 (s) \rightarrow CaO (s) + CO_2 (g)}$

Question 4

Predict how the entropy of the substance is affected in the following process: $\mathrm{CH_4 (g,\ 125^\circ C) \rightarrow CH_4 (g,\ 200^\circ C)}$

Accepted Answer

Increases

Question 5

Which of the following processes shows a decrease in entropy of the system?

Accepted Answer

$\mathrm{H_2O (l) \rightarrow H_2O (s)}$

Question 6

Which of the following best describes entropy ($S$)?

Accepted Answer

A measure of disorder or randomness in a system

Question 7

Which of the following scenarios would result in the greatest increase in entropy?

Accepted Answer

Dissolving solid KCl in water

Question 8

A reaction occurs in which two gases combine to form a solid. What is the expected sign of $\Delta S$ for this reaction?

Accepted Answer

Negative

Question 9

Which of the following best explains why the entropy increases when a solid melts to a liquid?

Accepted Answer

The particles in a liquid have more freedom of movement than in a solid.

Question 10

Which process would you expect to have the largest positive entropy change ($\Delta S$)?

Accepted Answer

Sublimation of dry ice ($\mathrm{CO_2 (s) \rightarrow CO_2 (g)}$)

Question 11

A chemical reaction in a closed container produces more moles of gas than it consumes. What is the most likely effect on the system's entropy?

Accepted Answer

Entropy increases

Question 12

Which of the following statements about entropy is FALSE?

Accepted Answer

Entropy is always conserved in a chemical reaction.

Question 13

Which of the following reactions is most likely to have a negative entropy change ($\Delta S < 0$)?

Accepted Answer

$\mathrm{2\ SO_2 (g) + O_2 (g) \rightarrow 2\ SO_3 (g)}$

Question 14

During which of the following changes does the entropy of the system decrease?

Accepted Answer

Condensation of water vapor to liquid

Question 15

Which of the following best describes the entropy change when a gas is compressed to a smaller volume at constant temperature?

Accepted Answer

Entropy decreases

Entropy: Physical and Chemical Changes in GOB Chemistry

Study Guide - Practice Questions