chemistry
posted by lee .
You have 67.0 mL of a 0.400 M stock solution that must be diluted to 0.100 M. Assuming the volumes are additive, how much water should you add?

you want 1/4 the concentration, so you need 4 times the volume.
So, add 3*67.0mL of water 
If 4.30 g of CuNO3 is dissolved in water to make a 0.560 M solution, what is the volume of the solution?

if 4.30 g of CuNO3 is dissolved in water to make a 0.560 M solution, what is the volume of the solution?