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

Answer:

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#.......