Question

280 mL of sulphur vapours weigh 3.2 g at NTP.
Calculate the number of atoms present per
molecule.

Answer 1

Answer:

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

number of atoms=S₈

Explanation: