Calculate the formula mass of potassium carbonate `(K_(2)CO_(3))` (Given : Atomic masses : `K = 39u , C = 12 u , O = 16 u`)

Explanation

We know that :
`{:("Formula mass",=,"Mass of",+,"Mass of",+,"Mass of"),("of" K_(2)CO_(3),,2"K atoms",,"one C atom",,3 'O' "atom"):}`
`= 2 xx 39 + 12 + 3 xx 16`
`= 78 + 12 + 48`
`= 138 u`
Thus, the formula mass of potassium carbonate is `138 u`.