A sample of Freon-12 (CF2Cl2) occupies 25.5 L at 298 K and 153.3 kPa. Find its volume at STP.

35.8 L

According to the combined gas law: pV=nRT

p=pressure

V=volume

T=temperature in Kelvin

R=the universal gas constant

n=number of moles of the gas

Rearranging the equation: n = pV/RT

n = (153.3kPa) (25.5L) / R (298K) = 13.1/R

At STP (standard temperature and pressure) p=100kPa and T=273.15K.

Rearranging the equation again: V=nRT/p V=[ (13.1/R) (R) (273.15K) ]/100kPa = 35.8L