Question

In an experiment to measure the molar mass of a gas, 250 cm³ of the gas was confined in a glass vessel. The pressure was 152 Torr at 298 K, and after correcting for buoyancy effects, the mass of the gas was 33.5 mg. What is the molar mass of the gas?

Answer 1

Answer: 16.34g/mol

Explanation:

V = 250 cm³ = 0.25L

T = 298 K

R = 0.082atm.L.K^-1.mol^-1

P = 152 Torr = (152/760)atm = 0.2atm

mass of the gas = 33.5 mg = 0.0335g

n =?

PV = nRT

n = PV / RT = (0.2x0.25)/(0.082x298)

n = 0.00205mol

n = Mass / Molar Mass

Molar Mass = Mass / n = 0.0335/0.00205 = 16.34 g/mol