First determine what’s needed.
As we only need ¼ of a liter, we need only ¼ as much CuSO
4
, or
¼ x 0.200 mole = 0.0500 mole CuSO
4
·
5H
2
O.
Calculate the mass in grams of 0.0500 mole of
CuSO
4
·
5H
2
O.
We need the molar mass of CuSO
4
·
5H
2
O.
The 5 waters of hydration are integral
to the copper sulfate crystals, so they must be included in calculating the molar mass.
copper
1 x
63.546 g/mol
sulfur
1 x
32.065 g/mol
oxygen
9 x
15.999 g/mol (4 from sulfate, 5 from 5H
2
O)
hydrogen
10 x
1.0079 g/mol
(from the 5 waters of hydration)
copper(II) sulfate pentahydrate
249.681 g/mol
