How much water should be added to 5.00 g of KCI to prepare a 0.500 M solution?

1 Answer
Apr 11, 2017

133.4 #cm^3#


Molarity is number of moles of solute divided by number of litres of solution.


Rearrange for V to give #V=n/M#

Number of moles of KCl is the mass divided by the molar mass of KCl which is 75.5 g/mol, so (5/75.5) = 0.0667 moles.

Now plug in the numbers: #V=n/m = 0.0667/0.5 = 0.1334# litres

So you need to add 0.1334 litres of 133.4 #cm^3# of water.

(NB: symbol for molarity is upper case M. m is metres).