A sample of gas occupies a volume of 50.0 milliliters in a cylinder with a movable piston. The pressure of the sample is 0.90 atmosphere and the temperature is 298 K. What is the volume of the sample at STP?

1 Answer
Dec 19, 2015

The new volume is 41 mL.

Explanation:

Use the combined gas law (P_1V_1)/T_1=(P_2V_2)/T_2P1V1T1=P2V2T2.
"STP=273.15 K and 1 atm"STP=273.15 K and 1 atm

Given/Known
P_1="0.90 atm"P1=0.90 atm
V_1="50.0 mL"V1=50.0 mL
T_1="298 K"T1=298 K
P_2="1 atm"P2=1 atm
T_2="273.15 K"T2=273.15 K

Unknown
V_2V2

Solution
Rearrange the equation to isolate V_2V2 and solve.

(P_1V_1)/T_1=(P_2V_2)/T_2P1V1T1=P2V2T2

V_2=(P_1V_1T_2)/(T_1P_2)V2=P1V1T2T1P2

V_2=(0.90cancel"atm"xx50.0"mL"xx273.15cancel"K")/(298cancel"K"xx1cancel"atm")="41 mL"