Question

At ntp 5.6 litre of a gas weight 8 gram the vapour density of the gases

Answer 1

Answer: 16

Explanation: we know that

Mole = given volume / 22.4

= 5.6/22.4

= 1/4 mol

We also know that

Mole = given mass /molecular mass

1/4 = 8/molecular mass

Therefore,

Molecular mass = 32

By the formula,

Molecular mass = 2 multiplied by

Vapour density

32/2 = V. D

So, vapour density = 16

Answer 2

Given: Volume at NTP, V = 5.6L

           Weight of gas, m = 8g

To Find: vapor density of the gas, V.D.

Solution:

To calculate vapor density, the formula used:

• V.D. = Molecular mass(M) / 2

To calculate M, the formula used:

• number of moles, n = mass(m) / Molecular mass of gas(M)  ⇒ 1

At NTP, 1 mol of gas occupies 22.4L of volume, and at 5.6 L of gas

Number of moles = (5.6 / 22.4 )mol        ⇒ 2

Equating equation 1 and equation2 :

5.6 / 22.4 = m / M

1 / 4 = 8 / M

   M = 4 x 8

        = 32 g

Applying the formula for V.D. -

V.D. = M / 2

       = 32 / 2

       = 16

V.D. = 16

Hence, the vapor density of the gas is 16.