Question

How many molecules are present in one ml of water vapours at STP -

(1) 1.69 × 10¹⁹ 

(2) 2.69 × 10^–19

(3) 1.69 × 10^–19 

(4) 2.69 × 10¹⁹

Answer 1

Correct Answer is: (4) 2.69 × 10¹⁹ 

∵ 22.4 litre water vapour at STP has = 6.023 × 10²³ molecules

∴ 1 × 10^–3 litre water vapours at STP has