What mass of Cr(NO_3)_3*9H_2O is required to make a 100*mL volume of a solution that is 2.00xx10^-3*mol*L^-1 with respect to Cr^(3+)?

1 Answer
anor277
May 28, 2017

We need a mass of approx...0.8*g

Explanation:

We use the relationship, "Concentration"="Moles of solute"/"Volume of solution",

and thus to get the "moles of solute", we take the product............

"Moles of solute"="Concentration"xx"Volume"

=100.0*mLxx10^-3*L*mL^-1xx0.0200*mol*L^-1

=2.000xx10^-3*mol.

And this represents a mass of...............

=2.000xx10^-3*molxx400.15*g*mol^-1=0.800*g.

Note that this question has been poorly specified. When you say "chromium nitrate nonahydrate" I have ASSUMED that you mean the Cr(+III) hydrate, Cr(NO_3)_3*9H_2O, whose formula mass is 400.15*g*mol^-1.

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