What is the molar mass of 56.75 g of gas exerting a pressure of 2.87 atm on the walls of a 5.29 l container at 230 k?

We first need to find the number of moles of gas in the container

PV = nRT

where;

P - pressure - 2.87 atm x 101 325 Pa/atm = 290 802.75 Pa

V - volume - 5.29 x 10⁻³ m³

n - number of moles

R - universal gas constant - 8.314 Jmol⁻¹K⁻¹

T - temperature - 230 K

substituting these values in the equation

290 802.75 Pa x 5.29 x 10⁻³ m³ = n x 8.314 Jmol⁻¹K⁻¹ x 230 K

n = 0.804 mol

the molar mass = mass present / number of moles

molar mass of gas = 56.75 g / 0.804 mol

therefore molar mass is 70.6 g/mol