Which of the following is the correct molar mass of sodium sulfate, Na2SO4?

• A. 98.08 g/mol
• B. 142.04 g/mol
• C. 156.00 g/mol
• D. 120.06 g/mol

Answer: (B)

Verified step by step guidance

1. Identify the chemical formula of sodium sulfate, which is Na\_2SO\_4. This means the compound contains 2 sodium (Na) atoms, 1 sulfur (S) atom, and 4 oxygen (O) atoms.
2. Find the atomic masses of each element from the periodic table: 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 contributions together to find the molar mass of sodium sulfate: total molar mass = (2 × 22.99) + (1 × 32.07) + (4 × 16.00).
5. Compare the calculated molar mass with the given options to determine which one matches the correct molar mass of sodium sulfate.