For a fixed mass of gas at constant pressure, the volume is directly proportional to temperature (in Kelvin). This is mathematically
\[ V = constant x T \]
That means, for example, that if you double the temperature from, say to 300 K to 600 K, at constant pressure, the volume of a fixed mass of the gas will double as well. You can express this mathematically as
Is this consistent with pV = nRT ?
- You have a fixed mass of gas, so n (the number of moles) is constant.
- R is the gas constant.
- Charles' Law demands that pressure is constant as well.
If you rearrange the pV = nRT equation by dividing both sides by p, you will get
V = nR/p x T
But everything in the nR/p part of this is constant. That means that V = constant x T, which is Charles' Law.
Contributors and Attributions
Jim Clark (Chemguide.co.uk)