Question

If the mass of 3.011x102 molecules of a gaseous compound in STP is 3.2 g, the gram molecular significance of the compound is determined. What is the volume of 3.2 g gaseous compound in STP?​

Answer 1

The mass of 3.011 × 10²² molecules of a gaseous compound in STP is 3.2 g.

To find : The volume of 3.2 g gaseous compound in STP.

solution : we know, mass of 1 mole of molecules of any compound is molecular mass of that compound.

but 1 mole of molecules = 6.022 × 10²³ molecules

so, mass of 6.022 × 10²³ molecules of a compound = molecular mass of that compound.

here mass of 3.011 × 10²² molecules = 3.2g

so, mass of 6.022 × 10²² molecules = 6.4 g

and also mass of 6.022 × 10²³ molecules = 64g

hence molecular mass of compound = 64 g/mol

now volume of gas in STP = no of moles × 22.4 L

= (given mass)/molecular mass × 22.4 L

= 3.2/64 × 22.4 L

= 1/20 × 22.4 L

= 1.12 L

Therefore the volume of gaseous compound in STP is 1.12 L