1. Zoek de molaire massa van elke component:

* mgso₄:

* Mg:24.31 g/mol

* S:32.06 g/mol

* O:16.00 g/mol (x 4) =64,00 g/mol

* Totale molaire massa van mgso₄ =24,31 + 32.06 + 64,00 =120,37 g/mol

* 7h₂o:

* H:1.01 g/mol (x 2 x 7) =14,14 g/mol

* O:16.00 g/mol (x 7) =112,00 g/mol

* Totale molaire massa van 7h₂o =14.14 + 112,00 =126.14 g/mol

2. Vind de totale molaire massa van Epsom -zout:

* Totale molaire massa van mgso₄ · 7h₂o =120,37 g/mol + 126,14 g/mol =246,51 g/mol

3. Bereken het percentage per massa water:

* (Massa water / totale massa Epsom -zout) x 100%

* (126,14 g/mol/246,51 g/mol) x 100% = 51,17%

Daarom is het percentage water in Epsom -zout (MGSO₄ · 7H₂O) ongeveer 51,17%.