WHAT IS THE MOLARITY OF A SOLUTION PREPARED BY DISSLOVING 4.92 GRAMS OF CALCIUM NITRATE, Ca(NO3)2 in 250 mL OF WATER?
CHEMISTY - DrBob222, Monday, July 21, 2008 at 10:28pm
Remember the definition.
M = #mols/L.
# mols = grams/molar mass.
Post your work if you get stuck.
CHEMISTY - Persia, Monday, July 21, 2008 at 10:36pm
Dr. Bob222 I'm not following. Would you please further explain?
CHEMISTY - DrBob222, Monday, July 21, 2008 at 10:52pm
Plug in the numbers.
# mols = g/molar mass = 4.92/molar mass Ca(NO3)2 = xx mols Ca(NO3)2.
Then M = #mols/L = xxmols/0.250 L = ?? M.
CHEMISTY - DrBob222, Monday, July 21, 2008 at 10:55pm
Technically, the problem should have said in 250 mL of SOLUTION. There is a difference. Or the problem could have said dissolve in a little water and make to a final volume of 250 mL. Or they could have asked for the molality and given the density and calculated the molarity that way; however, I think, in the spirit of the problem that it means 250 mL solution.