Which statement best describes Charles's Law?

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

Answer: (B)

Verified step by step guidance

1. Understand that Charles's Law describes the relationship between the volume and temperature of a gas when the pressure is held constant.
2. Recall the mathematical form of Charles's Law: \(V \propto T\) at constant pressure, which means volume is directly proportional to temperature measured in kelvins.
3. Express this relationship as an equation: \(\frac{V_1}{T_1} = \frac{V_2}{T_2}\), where \(V_1\) and \(V_2\) are volumes at temperatures \(T_1\) and \(T_2\) respectively.
4. Recognize that this law implies if the temperature of a gas increases, its volume increases proportionally, provided the pressure remains constant.
5. Compare this understanding with the given statements to identify that the correct description of Charles's Law is: 'At constant pressure, the volume of a gas is directly proportional to its temperature in kelvins.'