Question

Given a jar of gas (fixed volume and pressure) at 273.15K, the temperature is lowered to 0K, what happens to the volume?

Answer 1

Haven't you asked this before? The answer is the same. The volume does not change because it is fixed.

Explanation:

Why is the volume fixed? Because you specified it as fixed in the question. You could enclose the gas in a piston, so the volume could change.