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Moles

The Percentage of an Element in a Compound.

Example 2.

What is the percentage of Calcium in Calcium Carbonate?

The formula of calcium carbonate is CaCO₃.
RAM of  Ca = 40,  RAM of  C = 12,  RAM of  O = 16.

Method.
The RFM of calcium carbonate is (1 x 40) + (1 x 12) + (3 x 16),
=  40 + 12 + 48
=  100.            

40 of the 100 is due to calcium,
so the percentage of calcium in the compound is
(40 ÷ 100) x 100
= 40%.

Answer.  Calcium is 40% of calcium carbonate.

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