Question

The mass of a molecule of water is

(A) 3 × 10⁻²⁶ kg 

(B) 3 × 10⁻²⁵kg 

 (C) 1.5 × 10⁻²⁶ kg 

(D) 2.5 × 10⁻²⁶ kg 

Answer 1

The mass of a molecule of water is 3 × 10⁻²⁶ kg .

Explanation :-

6 × 10²³ molecules has mass = 18 g 

1 molecule has mass = 18/6×10²³  = 3 × 10^–23 g = 3 × 10^–26 kg.