What is the volume occupied by 10.8 g of argon gas at a pressure of 1.30 atm and a temperature of 408 K?

1 Answer
Nov 23, 2015

The volume of argon will be 6.96 L.

Explanation:

Use the ideal gas law PV=nRTPV=nRT, where nn is moles and RR is the gas constant.

Since we have mass and need moles, we must divide the given mass of argon by its molar mass (atomic weight on the periodic table in g/mol). The molar mass of argon is 39.948 g/mol.

"Ar":Ar:10.8"g Ar"xx(1"mol Ar")/(39.948"g Ar")="0.27035 mol Ar"10.8g Ar×1mol Ar39.948g Ar=0.27035 mol Ar

I am keeping a couple of guard digits to reduce rounding errors. I will round the final answer to three significant figures.

Ideal Gas Law

Given/Known
P="1.30 atm"P=1.30 atm
n="0.27035 mol"n=0.27035 mol
R="0.082057 L atm K"^(-1) "mol"^(-1)"R=0.082057 L atm K1mol1
https://en.wikipedia.org/wiki/Gas_constant
T="408 K"T=408 K

Unknown
VV

Equation
PV=nRTPV=nRT

Solution
Rearrange the equation to isolate volume, VV, and solve.

V=(nRT)/PV=nRTP

V=(0.27035cancel"mol"xx0.082057"L" cancel"atm" cancel("K"^(-1)) cancel("mol"^(-1))xx408cancel"K")/(1.30cancel"atm")="6.96 L Ar"