Question

If the concentration of a saturated solution at 0∘C is 12.5 gCuSO4/100 g soln, what mass of CuSO4⋅5H2O would be obtained? [Hint: Note that the solution composition is stated in terms of CuSO4 and that the solid that crystallizes is the hydrate CuSO4⋅5H2O.]

Answer 1

Mass of CuSO4.H2O obtained:
`m_(total)=19.52 g`

Step-by-step explanation:

The molecular weight of the salt is:
`M=159.5 g/mol`

In the solution: 12.5 g of CuSO4

In moles:
`n=(12.5 g)/(159.5 g/mol)=0.078 mol`

Mass of water:

5 moles of water per mol of salt:
`m=(5mol)/(1mol)*0.078mol*(18g)/(mol)=7.02 g`

Mass of CuSO4.H2O obtained:
`m_(total)=12.5 g + 7.02 g=19.52 g`