If the transformation occurs at constant temperature, then the answer is
halves
In fact, for a gas transformation occuring at constant temperature, we can use Boyle's law, which states that the product between the gas pressure P and the gas volume V remains constant:
[tex] PV=const. [/tex]
The equation can also be rewritten as:
[tex] V \sim \frac{1}{P} [/tex]
so, the volume of the gas is inversely proportional to its pressure. Therefore, if the pressure of the gas doubles, its volume will halve.
