Question

Calculate the number of moles and number of molecules present in 1.4 g of ethylene gas. What is the volume occupied by the same amount of ethylene?

Answer 1

Molecular mass of ethylene (CH₂-CH₂) = 1.4 g

Number of moles = `"Mass"/"Molecular mass"`

= `1.4/28`

= 0.05 moles

Now, number of molecules in 1 mole = 6.023 × 10²³

∴ Number of molecules in 0.05 moles = 6.023 x 10²³ × 0.05

= 0.3 × 10²³

= 3 × 10²² molecules

Volume occupied by 1 mole of ethylene = 22.4 L

∴ Volume occupied by 0.05 moles of ethylene = 22.4 × 0.05

= 1.12 L