Question

1. Calculate the relative molecular mass of water and carbon dioxide
2. Define molecular mass and formula unit mass
3. Calculate the formula unit mass of Mg(OH)2.​

Answer 1

Molecular formula of carbon dioxide =CO

2

1). The atomic mass of Carbon =12

The atomic mass of Oxygen =16

=1× atomic mass of carbon +2× atomic mass of oxygen.

=(1×12)+(2×16)=44

Hence the relative molecular mass of carbon dioxide =44.

2). Formula mass is defined as the sum of atomic masses of the ions present in the formula unit of an ionic compound whereas molecular mass is the sum of the atomic masses of the atoms in a molecule.

3). The molar mass of Mg(OH)2 is 58.33 g/mol. The molar mass of magnesium is 24.31 g/mol.