Question

An experiment shows that a 111 mL gas sample has a mass of 0.168 g at a pressure of 734 mmHg and a temperature of 34 ∘C. What is the molar mass of the gas?

Answer 1

hey there!:

Volume in liters ( V ) = 111 mL / 1000 => 0.111 L

Pressure in atm ( P )  = 734 / 760 => 0.965789 atm

temperature in Kelvin ( K )  = 34+273.15 => 307.15 K

Molar gas constant ( R ) = 0.0826 atm*L/mol*K

ideal gas  equation :

p*V = n*R*T

moles of gas:

n =  p*v / R*T

n = 0.965789 * 0.111 / 0.0826 * 307.15

n = 0.107202 / 25.37059

n = 0.004225 moles

Therefore:

Molar mass =  mass / moles of gas

molar mass = 0.168 / 0.004225

molar mass = 39.76 g/mol

Hope this helps!