Answer to Question #316497 in General Chemistry for Stemmeow

Question

If 160 g of KCI is dissolved in water to make 500ml solution,what is the molarity of the solution?

Answer 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

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