Question

A 515cm^3 flask contains 0.460 g of a gas at a pressure of 153 kPa and a temperature of 322K. What is the molecular mass of this gas

Answer 1

Answer:

Molecular mass, $M=28.89\ \text{g/mol}$

Explanation:

Given that,

Mass of gas, m = 0.46 g

Volume of the container, V = 515 cm^3

Pressure, P = 153 kPa

Temperature, T = 322 K

We need to find the molecular mass of this gas. We know that,

PV =nRT

n = no of moles

$n=\dfrac{PV}{RT}\\\\n=\dfrac{153\ kPa\times 0.515\ L}{8.31447\ LkPaK^{-1}{mol^{-1}}\times (322+273)\ K }\\\\n=0.01592\ \text{moles}$

No of moles = mass/molecular mass

Let molecular mass is M

$M=\dfrac{m}{n}\\\\M=\dfrac{0.46}{0.01592}\\\\M=28.89\ \text{g/mol}$

So, the molecular mass of this gas is $28.89\ \text{g/mol}$