Question

A sample of gas has a mass of 827 mg . Its volume is 0.270 L at a temperature of 88 ∘ C and a pressure of 975 mmHg . Find its molar mass.

Answer 1

Steps:

Mw = w * R * T / p * V

T = 88 + 273 => 361 K

p = 975 mmHg in atm :

1 atm  = 760 mmHg

975 mmg / 760 mmHg =>  1.28 atm

Therefore:

= 0.827 * 0.0821 * 361 /  1.28 * 0.270

=  24.51 / 0.3456

molar mass =  70.92 g/mol

Answer 2

Answer:

The molar mass of the gas is 70.83 g/mol.

Explanation:

Mass of the gas m= 827 mg = 0.827 g

Molar mass of gas = M

Pressure of the gas = 975 mmHg = 1.28 atm

Temperature of the gas = 88^C=  361 K

Using idal gas equation:

$PV=nRT$

$PV=\frac{m}{M}\times RT$

$M=\frac{mRT}{PV}$

$M=\frac{0.827 g\times 0.0820 atm L/mol K\times 361 K}{1.28 atm \times 0.270 L}=70.83 g/mol$

The molar mass of the gas is 70.83 g/mol.