The mass of Mg in Mg (OH)2 in its 10.2 gms is

Explanation:

To calculate the mass of Mg in the sample we must find the molar mass of Mg divide it by the molar mass of the sample and multiply it by the total mass of the sample

Molar mass (M) of Mg = 24g/mol

M of Mg (OH)2 = 24 + 2( 16 + 1)

= 24 + 34

= 58g/mol

Mass of Mg in Mg (OH)2 is

Hope this helps you.