A student needs to make #5.00xx10^1# mL of a potassium carbonate solution with a concentration of #3.3000xx10^(-2)# mol/L. What mass of potassium carbonate should they use to make the solution? (Answer to 3 s.d. in g)

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Answer 1 · 2017-05-24T07:30:59

We need a mass of #228*mg# of #"potassium carbonate"#...........

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

And thus #"moles of solute"="concentration"xx"volume".......#

So here...............

#"moles"=50*mLxx10^-3L*mL^-1xx3.30xx10^-2*mol*L^-1#

#=1.65xx10^-3*mol#.

Which represents a mass of ............................

#=1.65xx10^-3*cancel(mol)xx138.21*g*cancel(mol^-1)=0.228*g#.