Question

Calculate the volume of 54.0 g of C2H2 gas at standard temperature and pressure (STP). Use a molar mass with at least as many significant figures as the data given.

Answer 1

Molar mass of C₂H₂ = ( 2 x 12.01 ) + ( 2 x 1.0079 ) = 26.04 g / mol

We know that, Number of moles = Mass / Molar Mass

No. of moles = 54.0 g / 26.04 g / mol = 2.07 mol

We have, PV= n RT

Where, Pressure (P) = 1 atm

Volume (V)= ?

number of moles (n) = 2.07 mol

R = 0.082057 L atm / mol K

Temperature (T) = 273.15 K

Therefore, Volume of C₂H₂ gas = n RT /P

Volume of C₂H₂ gas = 2.07 mol x ( 0.082057 L atm / mol K ) x 273.15 K / 1 atm

Volume of C₂H₂ gas = 46.4 L