If molar mass of Na2SO4xnH2O is 304.04 mol/g, what is the hydration number of n

n = 9

Explanation:

Given parameters:

Molar mass of Na₂SO₄. nH₂O = 304.04gmol⁻¹

Solution

To find the hydration number n, we simply express atomic masses of the atoms in the compound as equal to the given molar mass.

Atomic mass of Na = 23g

S = 32g

O = 16g

H = 1g

Molar mass of the compound is evaluated as:

2 (23) + 32 + 4 (16) + n[2 (1) + 16] = 304.04

46 + 32 + 64 + 18n = 304.04

142 + 18n = 304.04

18n = 304.04 - 142

18n = 162.04

n = 9