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

Apr 11, 2017

133.4 $c {m}^{3}$

Explanation:

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

$M = \frac{n}{V}$

Rearrange for V to give $V = \frac{n}{M}$

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: $V = \frac{n}{m} = \frac{0.0667}{0.5} = 0.1334$ litres

So you need to add 0.1334 litres of 133.4 $c {m}^{3}$ of water.

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