Final answer:
To reduce the concentration of a 14 mL 8% alcohol solution to 7%, 2 mL of water must be added. This is calculated using the dilution formula C1V1 = C2V2 to find the new total volume, and then subtracting the initial volume to find the volume of water needed.
Step-by-step explanation:
To determine how much water should be added to 14 mL of 8% alcohol solution to reduce the concentration to 7%, we can use the concept of dilution which is rooted in the formula C1V1 = C2V2 where C1 and V1 are the concentration and volume of the initial solution, and C2 and V2 are the concentration and volume of the final diluted solution.
First, we calculate the amount of alcohol in the original solution:
- Original alcohol volume is 8% of 14 mL, which equals 1.12 mL.
Since the amount of alcohol remains constant upon dilution, we set up the equation:
- 1.12 mL / 14 mL = 7% / V2
By cross-multiplying and solving for V2, we get:
- V2 = 1.12 mL / 0.07 = 16 mL (total volume of the new solution)
Subtract the original volume from the total volume of the new solution:
- Amount of water to be added = V2 - 14 mL = 16 mL - 14 mL = 2 mL
Thus, 2 mL of water is needed to dilute the 14 mL of 8% alcohol solution to a 7% concentration.