Question

Calculate the gram molecular mass of oxygen if 385 cm³ of volume is occupied by 0.55 g of oxygen at S.T.P.

Answer 1

Given:

Volume of O₂ = 385 cm³

Mass of O₂ = 0.55 g

At STP, 1 mole of gas occupies 22,400 cm³.

Formula:

Molecular mass = `("Mass" xx 22400)/"Volume"`

= `(0.55 xx 22400)/385`

= 32 g mol^−1​

The gram molecular mass of oxygen is 32 g mol^−1​.