What is the molar mass of a gas if 1.070g of gas occupies 264mL?

Question

AT 100oC and 768 torr

Answer 1

768 torr = 768/760 atm and 100 oC = 100 + 273 = 373 K

First find the moles of the gas using the state equation of ideal gases:

p*V = n*R*T ==> n = p*V/R*T

n = (768/760)*0.264/0.082*373 = 8.82*10^(-3) mol

Then, because n = m/Mm where m the mass and Mm the molar mass of the gas:

Mm = m/n = 1.070/8.82*10^(-3) = 122.67 g/mol