An ideal sample weighing 1.28g at 127C (temp) and 1 atm has a volume of 0.250L. Determine the molar mass of the gas.

Molar mass of gas = 160 g/mol

Explanation:

Given data:

Mass of sample gas = 1.28 g

Temperature of sample gas = 127°C (127+273 = 400K)

Pressure of sample gas = 1 atm

Volume of sample gas = 0.250 L

Molar mass of gas = ?

Solution:

Formula:

PV = nRT

R = general gas constant = 0.0821 atm.L/ mol.K

Now we will put the values in formula.

1 atm × 0.250 L = n × 0.0821 atm.L/ mol.K ×400K

0.250 L.atm   = n ×32.84atm.L/ mol

n = 0.250 L.atm/32.84atm.L/ mol

n = 0.008 mol

Molar mass of gas:

Number of moles = Mass/molar mass

0.008 mol = 1.28 g / molar mass

Molar mass = 1.28 g / 0.008 mol

Molar mass = 160 g/mol