Determining formula mass:

1. Sodium Chloride, also called as table salt is used to flavor food, preserve meat, and in the preparation of large number of compounds. Determine its formula mass
2. Milk of magnesia which contains Mg (OH)₂ is used to treat acidity. Determine its formula mass.

Problem solving strategy

Add the atomic masses of all the atoms in the formula unit

Solution:

1. Formula mass of NaCl = 1 x Atomic mass of Na + 1 x Atomic mass of CI

= 1 x 23 + 1 x 35.5

= 58.5 amu

2. Formula mass of Mg (OH)₂ = 24 + 16 x 2 + 1 x 2

= 24 + 32 + 2

= 58 amu