Calculate the volume in dm^3 occupied by 60.0 g of ethane at STP.

Given : 

Mass of ethane at STP = 60.0 g 

To find : 

Volume of ethane

Formulae :

i. Number of moles = \(\frac{Mass\,of\,a\,substance}{Molar\,mass\,of\,the\,substance}\)

ii. Number of moles = \(\frac{Volume\,of\,a\,gas\,at\,STP}{Molar\,volume\,of\,a\,gas}\)

Calculation :

Molar volume of a gas = 22.4 dm³ mol^-1 at STP 

Molecular mass of ethane = 30 g mol^-1

Number of moles = \(\frac{Mass\,of\,a\,substance}{Molar\,mass\,of\,the\,substance}\)

= \(\frac{60.0\,g}{30\,g\,mol^{-1}}\)

= 2 mol

Number of moles of a gas (n) = \(\frac{Volume\,of\,a\,gas\,at\,STP}{Molar\,volume\,of\,a\,gas}\)

∴ Volume of the gas at STP = Number of moles of a gas (n) × Molar volume of a gas 

= 2 mol × 22.4 dm³mol^-1 

= 44.8 dm³

∴ Volume of ethane = 44.8 dm³