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mwilliams15 · Oct 10, 2007, 12:46 PM

In a solution of NiCl2, the Cl concentration is 0.06099 M. How many grams of NiCl2 are in 620 mL of this solution?

templelane · Oct 10, 2007, 12:53 PM

How do you think you should start it?

You need to work out the concentration of NiCl2. If you post what you think the answer is I'll guide you.

You already know how to do the second part by using the formula I gave earlier.

mwilliams15 · Oct 10, 2007, 12:59 PM

I don't know how to work out the concentration..
I'm thinking that the 620 mL needs to be changed to Liters.. so that's .620.
Next do you divide .06099 by 2 to get .030495 as the concentration for Ni?. then add that to .06099 to get a total concentration of .091485?
I'm sorry if I am making absolutely no sense but I really don't even know where to start lol.

templelane · Oct 10, 2007, 01:16 PM

You don't need to add the concentrations as the amount of molecule is one per 2 of Cl.
So I'd say the M would be 0.30.
The mL should be changed so that's good.
Now you have the volume and Molarity...
amount (moles) = molarity (mol l-1) x volume (l)

Once you have the moles then you can work out the grams
mass (g) = amount (moles) x molecular weight (g/mole)

Should be able to go form there.

If you are having lots of trouble with these questions you should speak with your teacher or if they are a bit rubbish then another member of the chemistry or biology department. It's getting really late over here so I won't answer any more tonight in case I work it out wrong and confuse you more!