Here's how to calculate the molar mass of Na₂SO₄ (sodium sulfate):

1. Identify the elements and their atomic masses:

* Na (Sodium): 22.99 g/mol

* S (Sulfur): 32.07 g/mol

* O (Oxygen): 16.00 g/mol

2. Determine the number of atoms of each element in the compound:

* Na: 2 atoms

* S: 1 atom

* O: 4 atoms

3. Calculate the molar mass:

(2 x 22.99 g/mol Na) + (1 x 32.07 g/mol S) + (4 x 16.00 g/mol O) = 142.04 g/mol

Therefore, the molar mass of Na₂SO₄ is 142.04 g/mol.