Question

The molar mass of the hydrated sodium sulfate is 322.1 g/mole. What is the formula of the hydrate salt?

Answer 1

Answer:

Na₂SO₄·10H₂O.

Explanation:

Hello.

In this case, since the anhydrous sodium sulfate is:

$Na_2SO_4$

Whose molar mass is:

$M=23+32+16*4=142 g/mol$

But the total hydrate's molar mass is 322.1 g/mol, we can compute the mass of water:

$m_{water}=322.1-142=180.1g/mol$

Thus, the molecules of water are found by diving the total mass of water by the mass of one mole of water:

$#water=\frac{180.1}{18}=10$

It means, that the formula is Na₂SO₄·10H₂O.

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