What is the percent composition of sodium in sodium phosphate (Na_3PO_4)?

• A. 42.1%
• B. 32.4%
• C. 25.8%
• D. 19.3%

Answer: (B)

Verified step by step guidance

1. Identify the chemical formula of sodium phosphate, which is \(\mathrm{Na_3PO_4}\), meaning it contains 3 sodium (Na) atoms, 1 phosphorus (P) atom, and 4 oxygen (O) atoms.
2. Find the atomic masses of each element from the periodic table: sodium (Na) is approximately 22.99 g/mol, phosphorus (P) is about 30.97 g/mol, and oxygen (O) is about 16.00 g/mol.
3. Calculate the molar mass of sodium phosphate by summing the masses of all atoms in the formula: \$3 \times 22.99 + 1 \times 30.97 + 4 \times 16.00$.
4. Calculate the total mass of sodium in the compound by multiplying the number of sodium atoms by the atomic mass of sodium: \$3 \times 22.99$.
5. Determine the percent composition of sodium by dividing the total mass of sodium by the molar mass of sodium phosphate and then multiplying by 100 to get a percentage: \(\left( \frac{3 \times 22.99}{\text{molar mass of } \mathrm{Na_3PO_4}} \right) \times 100\).