What is the molar mass of Mg3(PO4)2?

• A. 246.33 g/mol
• B. 215.22 g/mol
• C. 262.86 g/mol
• D. 310.31 g/mol

Answer: (C)

Verified step by step guidance

1. Identify the chemical formula given: \(\mathrm{Mg_3(PO_4)_2}\). This means the compound contains 3 magnesium (Mg) atoms, 2 phosphate (PO\(_4\)) groups.
2. Determine the atomic masses of each element involved (from the periodic table): Magnesium (Mg) = 24.31 g/mol, Phosphorus (P) = 30.97 g/mol, Oxygen (O) = 16.00 g/mol.
3. Calculate the total mass contributed by magnesium: multiply the number of Mg atoms by its atomic mass: \$3 \times 24.31$ g/mol.
4. Calculate the total mass contributed by the phosphate groups: each phosphate group has 1 phosphorus and 4 oxygen atoms, so calculate the mass of one PO\(_4\) group as \$30.97 + 4 \times 16.00$ g/mol, then multiply by 2 for the two groups.
5. Add the total masses of magnesium and phosphate groups together to find the molar mass of \(\mathrm{Mg_3(PO_4)_2}\): \(\text{mass of Mg} + \text{mass of 2 PO}_4\).