What is the molar mass of Na_2SO_4 (sodium sulfate)?

• A. 120 g/mol
• B. 142 g/mol
• C. 156 g/mol
• D. 98 g/mol

Answer: (B)

Verified step by step guidance

1. Identify the chemical formula of sodium sulfate, which is \(\mathrm{Na_2SO_4}\).
2. List the atomic masses of each element involved: sodium (Na) = 22.99 g/mol, sulfur (S) = 32.07 g/mol, and oxygen (O) = 16.00 g/mol.
3. Calculate the total mass contributed by each element by multiplying the atomic mass by the number of atoms in the formula: for sodium, multiply 22.99 g/mol by 2; for sulfur, multiply 32.07 g/mol by 1; for oxygen, multiply 16.00 g/mol by 4.
4. Add all these individual masses together to find the molar mass of \(\mathrm{Na_2SO_4}\): \$2 \times 22.99 + 1 \times 32.07 + 4 \times 16.00$.
5. Sum the values from the previous step to get the total molar mass of sodium sulfate in g/mol.