A 12.0 L sample of gas is at STP. What would be its new volume if its pressure was decreased to 575 mmHg and its temperature was doubled?

1 Answer
May 5, 2016

V_2=31.7LV2=31.7L

Explanation:

Let us first list the given data:

Position 1:
STP means that P=1atm=760mmHgP=1atm=760mmHg and T=273KT=273K.
The volume occupied by the gas is V=12.0LV=12.0L.

Position 2:
The new conditions are:
P=575mmHgP=575mmHg and T=2xx273=546KT=2×273=546K.
V=?V=?

To find the volume of the gas at position 2, we can rearrange the ideal gas law: PV=nRTPV=nRT to be:

(PV)/T=kPVT=k where k=nRk=nR, which is constant.

Therefore, (P_1V_1)/(T_1)=(P_2V_2)/(T_2)P1V1T1=P2V2T2

=>V_2=(P_1V_1)/(T_1)xx(T_2)/(P_2)=(760cancel(mmHg)xx12.0L)/(273cancel(K))xx(546cancel(K))/(575cancel(mmHg))=31.7L