Mass of solute in a solution of known volume and molarity

whittfred Wed, 08/15/2007 - 09:05

How many grams of CaCl2 are contained in 350ml of 0.0650 M CaCl2 solution?  Atomic Wts.: Ca=40.1, Cl=35.5

I don't know where to start with this one, the answer I get is (2.05 x 10 -4 g)

Molarity stands for moles per liter.  Remember, we always want to cancel out units.  The only way to get to grams is by way of moles.  So we need to turn a volume of a solution into moles and turn that into grams

Volume * moles/Volume * grams/mole will give you grams

Double check by making sure you have the correct units.  If you don't get grams as your answer (by canceling out your units) you will get some weird answer with volume^2/grams

AFTER DOING WHAT YOU SAID THE ANSWER I CAME UP WITH WAS: 2.53g  does this seem correct  ???

Yea, that's right.