Calculate the change in entropy that occurs in the system when 1.00 mole of diethyl ether (C₄H₁₀O) condenses from a gas to a liquid at its normal boiling point (34.6 °C). See Table 11.7 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 transitions from gas to liquid, such as diethyl ether condensing, 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. For diethyl ether, the heat of vaporization will provide the necessary energy value to determine the entropy change when it condenses.

Phase Change and Temperature

Phase changes, such as condensation, occur at specific temperatures known as boiling or melting points. The normal boiling point of diethyl ether is 34.6 °C, which is the temperature at which it transitions from gas to liquid under standard atmospheric pressure. Understanding the relationship between temperature and phase changes is essential for calculating thermodynamic properties like entropy.