Question

How many grams are there in the following? 

(i) 2 moles of a hydrogen molecule, H₂ 

(ii) 3 moles of chlorine molecule, Cl₂ 

(iii) 5 moles of sulphur molecule, S₈ 

(iv) 4 moles of a phosphorous molecule, P₄ 

Answer 1

(i) 2 moles of a hydrogen molecule, H₂

Mass of 1 mole of hydrogen molecule = 2 g

Mass of 2 moles of hydrogen molecule = 2 × 2 = 4 g.

(ii) 3 moles of chlorine molecule, Cl₂ 

Mass of 1 mole of chlorine molecule = 71 g

Mass of 3 moles of chlorine molecules = 71 × 3 = 213 g.

(iii) 5 moles of sulphur molecule, S₈ 

Mass of 1 mole of sulphur molecule = 32 g 

Mass of 5 moles of sulphur molecules = 32 × 5 = 160 g. 

(iv) 4 moles of the phosphorous molecule, P 

Mass of 1 mole of phosphorous molecule = 30.97 g 

Mass of 4 moles of phosphorous molecules = 30.97 × 4 = 123.88 g.