In this problem, we are asked to find the new concentration.
So, we use the dilution equation;
M1V1 = M2V2
Where M1 = concentration in molarity (moles/Liters) of the concentrated solution,
V2 =volume of the concentrated solution,
M2 =concentration in molarity of the dilute solution, and
V2 = volume of the dilute solution.
Before substituting the formula, convert the given mL to L since the unit for molarity is (moles/Liter).
Use the conversion factor (1000 mL = 1 L), so:
10.0 mL = 0.01 L
100 mL= 0.1 L
Now, we substitute the given (in liters) to the formula.
(0.50 M) (0.01 L) = M2(0.1 L)
M2 = [(0.50 M) (0.01 L)] / 0.1 L
M2 = 0.05 M