What percent of carbon is calcium oxalate (CaC2O4)?

To find the percent of carbon in calcium oxalate (CaC₂O₄), we first need to determine the molar mass of carbon in the compound.

Calcium oxalate consists of:

• 1 atom of calcium (Ca)
• 2 atoms of carbon (C)
• 4 atoms of oxygen (O)

Each element has the following molar masses:

• Calcium (Ca): 40.08 g/mol
• Carbon (C): 12.01 g/mol
• Oxygen (O): 16.00 g/mol

Calculating the total molar mass of calcium oxalate:

• Molar mass of Ca = 40.08 g/mol
• Molar mass of 2C = 2 × 12.01 g/mol = 24.02 g/mol
• Molar mass of 4O = 4 × 16.00 g/mol = 64.00 g/mol

Adding these together:

Molar mass of CaC₂O₄ = 40.08 + 24.02 + 64.00 = 128.10 g/mol

Now, we find the mass contributed by the carbon atoms:

Mass of C = 24.02 g/mol (from 2 carbon atoms)

To find the percentage of carbon in calcium oxalate, we use the formula:

Percentage of C = (mass of C / molar mass of CaC₂O₄) × 100%

So:

Percentage of C = (24.02 g/mol / 128.10 g/mol) × 100% ≈ 18.75%

Thus, approximately 18.75% of calcium oxalate is carbon.