Question

a gas mass 1.6kg kept at 760mm Hg preasure and 273 temapture. occupies a volume of 1.12l determine the molar gas and its vapour density with respect hydrogen​

Answer 1

Given:

Pressure = 760mm Hg

Temperature = 273K

Volume = 1.12 L

mass of gas = 1.6kg

To find:

Molar mass of gas and vapour density

Solution:

The required formula used is as follows-

                           PV = nRT

This is ideal gas equation.

here, P = pressure ( 760mm Hg)

        V = volume ( 1.12 L )

         T = temperature (273K)

          n = number of moles of gas

          R = gas constant (0.082 L atm mol⁻¹ K⁻¹)

putting all the values in above equation,

    $n = \frac{PV}{RT}$

    $n = \frac{760 \times 1.12}{0.082 \times 273}$

    n = 38.024 moles

we know that,

                       $n = \frac{given mass}{molar mass }$

                       $Molar mass = \frac{1.6 \times 1000}{38.024}$

                      Molar mass = 42.08 gmol⁻¹

now, to vapour density, we know that,

          $VD = \frac{MM}{2}$

here, vapour density = VD

        molar mass = MM

so,

         $VD = \frac{42.08}{2}$

       Vapour Density = 21.04 gmol⁻¹

Therefore, Molar mass is 42.08 gmol⁻¹ and Vapour density is 21.04 gmol⁻¹.