Question

A sample of gas has a mass of 38.6 mg . Its volume is 222 mL at a temperature of 53 ∘C and a pressure of 884 torr .

Part A Find the molar mass of the gas.

Answer 1

we have:

P = 884.0 torr

= (884.0/760) atm

= 1.1632 atm

V = 222.0 mL

= (222.0/1000) L

= 0.222 L

T = 53.0 oC

= (53.0+273) K

= 326 K

find number of moles using:

P * V = n*R*T

1.1632 atm * 0.222 L = n * 0.08206 atm.L/mol.K * 326 K

n = 9.653*10^-3 mol

mass of solute = 38.6 g

we have below equation to be used:

number of mol = mass / molar mass

9.653*10^-3 mol = (38.6 g)/molar mass

molar mass = 4000 g/mol

Answer: 4000 g/mol