Question

How many grams of sodium are in 0.820 moles of na2so4?

Answer 1

the molar mass of a compound is the sum of the products of the atomic masses by the number of atoms of the element.
molar mass of Na₂SO₄ is - 142 g/mol.
1 mol of Na₂SO₄ has a mass of 142 g.
In 1 mol of Na₂SO₄ the mass of Na is 23 g/mol x 2 = 46 g.
                             
Mass of Na in 1 mol of Na₂SO₄ is - 46 g
                           
mass of Na in 0.820 mol of Na₂SO₄ - 46 g /1 mol x 0.820 mol = 37.72 g.
mass of Na is 37.72 g

Answer 2

Explanation:

Number of moles are defined as given mass divided by molar mass of the compound or substance.

Mathematically,     Number of moles = $\frac{mass given}{molar mass}$

Since, it is given that number of moles is 0.820 and molar mass of $Na_{2}SO_{4}$ is 142 g/mol.

Therefore, calculate the mass as follows.

         Number of moles = $\frac{mass given}{molar mass}$

               0.820 moles = $\frac{mass given}{142 g/mol}$

           mass given = 116.44 g

Thus, we can conclude that there are 116.44 grams of sodium in 0.820 moles of $Na_{2}SO_{4}$.