Help me with gas chemistry please

Question

A balloon has a volume of 150 mL. If the pressure is kept constant, while the temperature is halved, the volume of the balloon:

A. Will also be doubled

B. Will be halved   

C.  Will be squared

D. Will not change

Answer 1

Consider the ideal gas equation PV = nRT and solve for V to get V = nRT/P.

As P is constant, the the term nR/P stays constant, so the equation can be written V = KT where K represents nR/P. As you can see, if T is halved, the volume is also halved.

The answer is B.