How many moles of copper sulfate, CuSO4 are in a o.671 g sample?

How do I start on this?

1 answer

mols = grams/molar mass by formula OR if you want to do it with dimensional analysis it is
0.671 g CuSO4 x (1 mol CuSO4/159 g CuSO4) = ?? Note how the g CuSO4 cancel ( the unit we don't want to keep) and leaves the mol CuSO4 (the unit we want to keep and the unit to which we are trying to convert). The 159 is an estimate of the molar mass of CuSO4. You will need to look it up to work the problem exactly.