If 25.0 g of K_2CO_3, potassium carbonate, are dissolved in 450 cm^3 of solution, what is the molarity?

1 Answer
Jan 26, 2017

Approx. 0.4*mol*L^-1

Explanation:

"Molarity" = "Moles of potassium carbonate (mol)"/"Volume of solution (L)"

=((25*g)/(138.21*g*mol^-1))/(0.450*L)~=0.4*mol*L^-1

Note that when we do the calculation this wa we automatically get appropriate units. We seek the molarity, which should properly have units of mol*L^-1, and lo and behold, the expression gives us such units as the grams cancel out, and the mol^-1 is inverted to give 1/(1/(mol))=mol.......