Question

What is the mass of: 

(a) 0.2 mole of oxygen atoms? 

(b) 0.5 mole of water molecules?

Answer 1

(a) Mass of one mole of oxygen atoms = 16g 

Then, mass of 0.2 mole of oxygen atoms = 0.2 × 16g = 3.2g 

(b) Mass of one mole of water molecule = 18g 

Then, mass of 0.5 mole of water molecules = 0.5 × 18g = 9g