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Question
Calculate the formula masses of the following compounds :
- Calcium chloride
- Sodium carbonate
(Given : Atomic masses : Ca = 40 u ; Cl = 35.5 u ; Na = 23 u ; C = 12 u; O = 16 u)
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Solution
- Formula mass of calcium chloride = mass of one Ca atom + mass of two Cl atoms = 40 + 2 × 35.5 = 111
Thus, the formula mass of calcium chloride is 111 u. - Formula mass of sodium carbonate = mass of two Na atoms + mass of one C atom + mass of three O atoms = 2 × 23 + 12 + 3 × 16 = 106
Thus, the formula unit of sodium carbonate is 106 u.
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