Which one of the following best describes Charles's Law?

• A. At constant volume, the pressure of a gas is directly proportional to its absolute temperature.
• B. The total pressure of a mixture of gases is equal to the sum of the partial pressures of each gas.
• C. At constant temperature, the pressure of a gas is inversely proportional to its volume.
• D. At constant pressure, the volume of a gas is directly proportional to its absolute temperature.

Answer: (D)

Verified step by step guidance

1. Recall that Charles's Law describes the relationship between the volume and temperature of a gas when the pressure is held constant.
2. Understand that Charles's Law states that the volume of a gas is directly proportional to its absolute temperature (measured in Kelvin) at constant pressure.
3. Express Charles's Law mathematically as \(V \propto T\) or \(\frac{V_1}{T_1} = \frac{V_2}{T_2}\), where \(V\) is volume and \(T\) is absolute temperature.
4. Note that this means if the temperature of a gas increases, its volume increases proportionally, provided the pressure does not change.
5. Compare this to other gas laws: for example, Boyle's Law relates pressure and volume at constant temperature, and Dalton's Law relates total pressure to partial pressures in a gas mixture.