The pressure in a syringe

Question

When the volume is 25.0 mL, the pressure in a syringe will be 855 torr.

what is the pressure for the volume  (50.0 mL)?

Use P1V1T2=P2V2T1

Answer 1

If we assume that the temperature and number of moles are constant,

(855 torr)(25 ml) = (P2)(50 ml)

P2 = (855 torr)(25 ml)/50 ml

P2 = 427.5 torr = 428 torr