Question

How much water should be added to 5.00 g of KCl to prepare a 0.500 m
solution? *
Molality = moles of solute
Kg of solvent
100 g
38g
500 g
134 g
Other

Answer 1

Answer:133.4

c

m

3

Explanation: Explanation:

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

M

=

n

V

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

c

m

3

of water.

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