Question

Find out the weight % of carbon in 50 g $CaCO_3$ sample.

Answer 1

12.00%

Answer 2

The weight percentage of an element in a compound is calculated by dividing the total mass of that element in one mole of the compound by the molar mass of the compound, and then multiplying by 100. The sample size (50 g) is irrelevant as the percentage composition is an intrinsic property of the compound.

For $CaCO_3$, the molar mass is $40.08 (Ca) + 12.01 (C) + 3 \times 16.00 (O) = 100.09$ g/mol. The mass of carbon in one mole is $12.01$ g. Thus, the weight percentage of carbon is $(12.01 / 100.09) \times 100\% \approx 12.00\%$.