The molar mass of sodium sulfate (Na₂SO₄) is 142.04 g/mol. Here's how to calculate it:

* Sodium (Na): Atomic mass = 22.99 g/mol. There are two sodium atoms, so 22.99 g/mol * 2 = 45.98 g/mol.

* Sulfur (S): Atomic mass = 32.07 g/mol.

* Oxygen (O): Atomic mass = 16.00 g/mol. There are four oxygen atoms, so 16.00 g/mol * 4 = 64.00 g/mol.

Total Molar Mass: 45.98 g/mol + 32.07 g/mol + 64.00 g/mol = 142.05 g/mol