Question

magnesium sulfatee is often added to water insoluble liquid products of chemical reactions to remove any unwanted water. MgSO4 readily absorbs water to form two different hydrates. one of these hydrates is found to contain 13.0% H2O and 87.0% MgSO4. what is the name of this Hydrate?

Answer 1

Answer:  The name of this Hydrate is magnesium sulphate monohydrate.

Explanation:

Empirical formula is the simplest chemical formula which depicts the whole number of atoms of each element present in the compound.

a) If percentage are given then we are taking total mass is 100 grams.

So, the mass of each element is equal to the percentage given.

Mass of $MgSO_4$ = 87.0 g

Mass of $H_2O$ = 13.0 g

Step 1 : convert given masses into moles

Moles of  $MgSO_4$ =$\frac{\text{ given mass }}{\text{ molar mass }}= \frac{67.0g}{120g/mole}=0.56moles$

Moles of $H_2O$ =$\frac{\text{ given mass}}{\text{ molar mass}}= \frac{13.0g}{18g/mole}=0.72moles$

Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.

For $MgSO_4$ = $\frac{0.56}{0.56}=1$

For  $H_2O$ =$\frac{0.72}{0.56}=1$

Hence the empirical formula is $MgSO_4.H_2O$

Thus the name is magnesium sulphate monohydrate.