Question

Entropy never decreases in a spontaneous process. Give an example to support this statement.

a) Ice melting into water.

b) Water freezing into ice.

c) Boiling water turning into steam.

d) Condensation of steam into water.

Answer 1

Entropy is a measure of disorder and a key factor in spontaneous processes, where the total entropy of an isolated system does not decrease. The melting of ice into water is a classic example of an entropy increase, embodying the second law of thermodynamics.

Step-by-step explanation:

Entropy, which is a measure of disorder or randomness in a system, often serves as a driving force in spontaneous processes. As per the second law of thermodynamics, the total entropy of an isolated system will not decrease over time. A classic example that illustrates an increase in entropy is the melting of ice into water. When ice at a temperature below 0°C in a room temperature environment begins to melt, it absorbs heat energy from the surroundings. This energy transfer increases the entropy of the ice as it transitions to a less ordered state - from solid to liquid.

In contrast, while water freezing into ice appears to involve a decrease in entropy due to solidification, the process overall still increases the entropy of the universe. This is because freezing releases heat into the environment, which increases the surrounding entropy more than the decrease caused by the water becoming ordered ice (H₂O(l) → H₂O(s)). It is this net increase in entropy that allows the process to be spontaneous when the water is below its freezing point.