how many milliliters of a 5% stock solution are needed to prepare 250ml of a 2% solution?
To find out how many milliliters of a 5% stock solution are needed to prepare 250 ml of a 2% solution, we can use the concept of dilution.
The formula for dilution is:
C1V1 = C2V2
Where:
C1 = concentration of the initial solution (stock solution)
V1 = volume of the initial solution (stock solution)
C2 = concentration of the final solution
V2 = volume of the final solution
In this case, we know the concentration and volume of both the initial and final solutions. Let's assign the values to the variables:
C1 = 5% = 0.05 (decimal form)
V1 = ?
C2 = 2% = 0.02 (decimal form)
V2 = 250 ml
Plugging these values into the formula:
0.05 * V1 = 0.02 * 250
Now, we can solve for V1:
V1 = (0.02 * 250) / 0.05
V1 = 50 ml
Therefore, 50 milliliters of the 5% stock solution are needed to prepare 250 ml of a 2% solution.