We need to dilute 0.400 mol of copper (II) sulfate, how do we know, how many weigh of 
we have to dilute??
It's simple.
Using a periodic table we can find the molar mass of
Then
now we can replace it
Then we have to dilute 63.84 grams of copper (II) sulfate in 1 L of water to obtain a solution with 0.400M
It's simple.
Using a periodic table we can find the molar mass of
Then
now we can replace it
Then we have to dilute 63.84 grams of copper (II) sulfate in 1 L of water to obtain a solution with 0.400M