Question

How many grams of CaCl2 would be required to produce a 3.5 M (molar) solution with a volume of 2.0 L?
I think I have done "okay" working on the problem, but I'm starting to worry I'm missing something. Please help.

Answer 1

Can I see your work so far with solving this? Remember the equation
Molarity = Moles/Litres

Answer 2

Okay so I know the volume is 2.0L and the molarity is 3.5M. I reached the conclusion that the moles was 7 however, Im not sure if thats right. I also don't know if that would be the grams in the problem. The examples I was given before the assignment problem was a bit confusing. The first one was telling me to find the moles in a problem like this. Although the second example was worded more like this and was looking for the mass. I'm just starting to get a little flustered with the wording of the question I think.

Answer 3

So far you are correct with your moles of CaCl2 are correct! now all you need left is the process of getting to grams of CaCl2! now the molecular weight of this is 110.98 g/mol so set up your stio. and lets go through the mole!
7moles CaCl2* *(110.98 g CaCl2)/1mole and you get...... GRAMS!

Answer 4

moles cancel out so you're left with grams

Answer 5

^ @lolaismy is correct. You need 7 moles of \(CaCl_2\) total, and if one mole of \(CaCl_2\) weighs 111g, then 7 moles should weigh 7 times as much!

Answer 6

Then I get 777g is that not to much?

Answer 7

nope that sounds right! :D

Answer 8

Thank you so much for the help!!