Question

What is the molar mass of a gas which occupies 48.7 L at 111oC under 698 torr of pressure and has a mass of 21.5 grams?

Answer 1

Molar mass of the gas = 15.15 g/mol

Step-by-step explanation:

PV = nRT

Where,

P = pressure

n = No. of moles

R = Gas constant

T = Temperature

P = 698 torr, 1 torr = 0.00131579 atm

`698\;torr = 698*0.00131579 = 0.9184\;atm`

Temperature = 111 °C = 100 + 273.15 = 384.15 K

V = 48.7 L

R = 0.082057 L atm/mol K

Now, PV = nRT

`n = (PV)/(RT)`

`n = (0.9184*48.7)/(0.082057*384.15)`

=1.4189 mol

Molar mass = Mass/ No. of moles

= 21.5/1.4189

=15.15 g/mol