Question

calculate the number of molecules of a gas occupies 280 ml at the ntp

Answer 1

As we know density of a gas = Mass/Volume = 3.2gm / 280mL

Molecular mass = Molar volume x density

As molar volume at N.T.P = 22.4L = 22.4 x 1000mL

So molecular mass = 22.4 x 1000 x 3.2 / 280 = 256

Now molecular formula = n x Empirical formula

n = Molecular mass / Empirical formula mass

Empirical formula mass for sulphur is = 32

So, n = 256 / 32 = 8

Hence molecular formulaof sulphur vapour is = 8 x (S)

= S8