Question

Convert 9.52 x 10⁴ g O to atoms of Ca(OH)2

Answer 1

Molar mass of O is 16 gmol^-1

16 g atom means 1 mol O atoms = 6.023 × 10²³ no of O atoms.

So 9.52 × 10⁴ g O means = (9.52 × 10⁴)×(6.023× 10²³) \ 16 = 3.58 × 10²⁷ atoms of O.

Here Ca(OH)₂ is a compund so it is present as unit of calcium hydroxide not as atoms

So in one Ca(OH)₂ 2 O atoms present

That means 2 O atoms present in 1 Ca(OH)₂

So 3.58 × 10²⁷ O atoms present in

= 3.58 × 10²⁷ \ 2 = 1.79 × 10²⁷ Ca(OH)₂ unit.

That means Ans is 1.79× 10²⁷ .