Which element contributes the most to the molar mass of Ca3(PO4)2?

Which element contributes the most to the molar mass of Ca3(PO4)2?

• A. Calcium
• B. Oxygen
• C. Phosphorus
• D. Hydrogen

Answer: (B)

Molar mass is found by adding up the masses of all atoms in the formula. In Ca3(PO4)2 there are 3 calcium atoms, 2 phosphorus atoms, and 8 oxygen atoms. Using approximate atomic masses: Ca ≈ 40.1, P ≈ 30.97, O ≈ 16.00. The contributions are about 3×40.1 ≈ 120.3 for calcium, 2×30.97 ≈ 61.9 for phosphorus, and 8×16.00 ≈ 128.0 for oxygen. Oxygen adds up to the largest total mass, so it contributes the most to the molar mass. Hydrogen isn’t present in this compound.

Molar mass is found by adding up the masses of all atoms in the formula. In Ca3(PO4)2 there are 3 calcium atoms, 2 phosphorus atoms, and 8 oxygen atoms. Using approximate atomic masses: Ca ≈ 40.1, P ≈ 30.97, O ≈ 16.00. The contributions are about 3×40.1 ≈ 120.3 for calcium, 2×30.97 ≈ 61.9 for phosphorus, and 8×16.00 ≈ 128.0 for oxygen. Oxygen adds up to the largest total mass, so it contributes the most to the molar mass. Hydrogen isn’t present in this compound.