You need to prepare 100ml of a 0.125m cuso4 stock solution. explain how you would prepare?

First thing to do is to determine the amount in grams of copper sulfate you need for the given concentration. We calculate as follows:

0.125 mol/L (.1 L) = .0125 mol CuSO4
0.125 mol (159.609 g / mol ) = 2.00 g CuSo4

We weigh the calculated amount above. Then, we dissolve in water in a 100-mL of volumetric flask. After dissolving every solute, fill the flask up to the mark.