Chemistry help!!! Molality problem?

Question

can anyone show me how to do this??

How many kilograms of H2O must be added to 75.5 g of Ca(NO3)2 to form a .500 m solution???

Answer 1

molality = moles of solute / kg. of solvent

In your problem, molality = 0.500m
moles of solute = 75.5 g / molecular mass of Ca(NO3)2.

then you can solve for kg of water