You wish to make a 0.200 M solution of NiSO4 (aq). How many grams of NiSO4 * 6H2O should you put in a 0.500 L volumetric flask?

Question

The answer is 26.3 g NiSO4 * 6H20 but I am not sure how to get there.

Answer 1

Find moles first:
That is M x L = 0.20 x 0.500L = ?
Then convert from moles to grams with moles/molar mass. You want to use the molar mass of NiSO4.6H2O:
0.10 mol x 262.84 g/mol = 26.28 g of NiSO4.6H2O