Calculate the gram molecular mass of calcium phosphate, Ca3(PO4)2. (Atomic masses: Ca = 40, P = 30, O = 16)

1. Calcium part: $40 \times 3 = 120$. 2. One PO4 group: $30 + (16 \times 4) = 30 + 64 = 94$; two groups: $94 \times 2 = 188$. 3. Total $= 120 + 188 = 308$ g. Forgetting that the PO4 group is doubled (using 94 once) gives 214 g. _Source: Samacheer Kalvi (TN SCERT) Class 10 Science, Unit 7 Atoms and Molecules "Solved Problems", p.106_