What is the molar mass of calcium carbonate (CaCO3)?

What is the molar mass of calcium carbonate (CaCO3)?

• A. 100.09 g/mol
• B. 120.07 g/mol
• C. 40.00 g/mol
• D. 44.01 g/mol

Answer: (A)

Molar mass is found by adding the atomic masses of every atom in the formula. CaCO3 has one calcium, one carbon, and three oxygens. Using standard atomic masses: Ca 40.08 g/mol, C 12.01 g/mol, O 16.00 g/mol. Three oxygens contribute 3 × 16.00 = 48.00 g/mol. Total: 40.08 + 12.01 + 48.00 = 100.09 g/mol. That value matches the correct choice. The other numbers are for different substances or miscounts (for example, 44.01 g/mol is CO2, and 40.00 g/mol is calcium alone).

Molar mass is found by adding the atomic masses of every atom in the formula. CaCO3 has one calcium, one carbon, and three oxygens. Using standard atomic masses: Ca 40.08 g/mol, C 12.01 g/mol, O 16.00 g/mol. Three oxygens contribute 3 × 16.00 = 48.00 g/mol. Total: 40.08 + 12.01 + 48.00 = 100.09 g/mol. That value matches the correct choice. The other numbers are for different substances or miscounts (for example, 44.01 g/mol is CO2, and 40.00 g/mol is calcium alone).