Question

The number of moles of KCl in 100ml of 3 molar solution is?

Answer 1

The thing to remember about a solution's molarity is that you can express it as a fraction that has
1 L
of solution as the denominator.
In your case, a
2.0-M
potassium chloride solution contains
2.0
moles of potassium chloride, the solute, for every
1 L
of solution, which means that you can write it as
2.0 M
=
2.0 moles KCl
1 L solution
Now, you should know that
1 L
=
10
3

mL
This means that you can rewrite the molarity of the solution as
2.0 M
=
2.0 moles KCl
10
3
.
mL solution
So, you need to figure out how many moles of potassium chloride must be dissolved in water to make
100.0 mL
of
2.0 M
solution.
In other words, you must find the number of moles that when dissolved in
100.0 mL
are equivalent to
2.0
moles dissolved in