Question

How do I calculate the molecular weight of Mg(OH)2?

Answer 1

The molecular weight of Mg(OH)2 : 58 g/mol

Further explanation

Given

Mg(OH)2 compound

Required

The molecular weight

Solution

Relative atomic mass (Ar) of element : the average atomic mass of its isotopes  

Relative molecular weight (M)  : The sum of the relative atomic mass of Ar  

M AxBy = (x.Ar A + y. Ar B)  

So for Mg(OH)2 :

= Ar Mg + 2 x Ar O + 2 x Ar H

= 24 g/mol + 2 x 16 g/mol + 2 x 1 g/mol

= 24 + 32 + 2

= 58 g/mol