Question

what is the molarity of solution if 7.46g of KCl in 1 litre of solution​

Answer 1

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What is the molarity of a

K

C

l

solution made by dissolving 24.7 g of

K

C

l

in a total volume of 500. mL?

Chemistry Molarity

1 Answer

Stefan V.

Feb 27, 2016

0.663 mol L

−

1

Explanation:

In order to calculate the molarity of a solution, you need to know two things

the number of moles of solute present in solution

the total volume of the solution

The problem provides you with a

24.7-g

sample of potassium chloride,

KCl

, and a total volume of a solution of

500. mL

.

In order to find the number of moles of potassium chloride, your solute, use the compound's molar mass, which as you know tells you the mass of one mole of potassium chloride

24.7

g

⋅

molar mass of KCl



1 mole KCl

74.55

g

=

0.3313 moles KCl

Now, molarity is expressed per liter of solution. Since you dissolve

0.3313

moles of potassium chloride in

500. mL

of solution, you can say that

1.0 L

will contain

1.0

L

⋅

10

3

mL

1

L

⋅

0.3313 moles

500

.

mL

=

0.6626 moles KCl

This means that the molarity of the solution will be

c

=

0.663 mol L

−

1

The answer is rounded to three sig figs.