Which of the following correctly states Charles's Law?

• A. At constant volume, the pressure of a gas is directly proportional to its absolute temperature.
• B. At constant temperature, the pressure of a gas is inversely proportional to its volume.
• C. At constant pressure, the volume of a gas is directly proportional to its absolute temperature.
• D. At constant pressure, the volume of a gas is inversely proportional to its absolute temperature.

Answer: (C)

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. Charles's Law states that the volume of a gas is directly proportional to its absolute temperature (measured in Kelvin) at constant pressure.
3. Mathematically, Charles's Law can be expressed as \(\frac{V_1}{T_1} = \frac{V_2}{T_2}\), where \(V\) is volume and \(T\) is absolute temperature.
4. This means if the temperature of a gas increases, its volume increases proportionally, provided the pressure remains constant.
5. Review the given options and identify the one that matches this direct proportionality between volume and absolute temperature at constant pressure.