Percent Composition Chemistry Example 4

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Example 4

easy
What percent by mass of calcium carbonate (CaCO3\text{CaCO}_3) is oxygen? (Ca = 40.0840.08, C = 12.0112.01, O = 16.0016.00)

Solution

  1. 1
    Mass of oxygen in one mole of CaCO3\text{CaCO}_3 is 3×16.00=48.00 g3 \times 16.00 = 48.00\,\text{g}.
  2. 2
    Total molar mass is 40.08+12.01+48.00=100.09 g/mol40.08 + 12.01 + 48.00 = 100.09\,\text{g/mol}. Percent oxygen =48.00100.09×100%=48.0%= \frac{48.00}{100.09} \times 100\% = 48.0\%.

Answer

48.0% oxygen48.0\%\text{ oxygen}
Percent composition compares the mass contribution of one element to the total molar mass of the compound. Compute the part, divide by the whole, then convert to a percent.

About Percent Composition

Percent composition is the percentage by mass of each element in a chemical compound.

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More Percent Composition Examples

Example 1 easy

Calculate the percent composition by mass of each element in [formula].

Example 2 medium

Calculate the percent by mass of nitrogen in ammonium nitrate ([formula]).

Example 3 easy

What is the percent composition of carbon in [formula]? (C = 12.01, O = 16.00)

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