Calculate the change in entropy that occurs in the system when 1.50 mol of diethyl ether (C₄H₁₀O) condenses from a gas to a liquid at its normal boiling point (34.6 °C). See Table 12.7 for heats of vaporization.

Key Concepts

Entropy

Entropy is a measure of the disorder or randomness in a system. In thermodynamics, it quantifies the amount of energy in a physical system that is not available to do work. When a substance changes state, such as from gas to liquid, the entropy typically decreases because the molecules become more ordered in the liquid state.

Heat of Vaporization

The heat of vaporization is the amount of energy required to convert a unit mass of a substance from liquid to gas at its boiling point. This value is crucial for calculating changes in entropy during phase transitions, as it directly relates to the energy absorbed or released when a substance condenses or vaporizes.

Phase Change and Temperature

Phase changes, such as condensation, occur at specific temperatures known as boiling or melting points. During these transitions, the temperature remains constant while the substance changes state. Understanding the normal boiling point of diethyl ether (34.6 °C) is essential for calculating the entropy change, as it indicates the conditions under which the phase change occurs.