Determine the milliliters of water needed to prepare 2 oz of a 10% solution from a 12.5% solution and distilled water.
To determine the milliliters of water needed, we can use the equation:
C1V1 + C2V2 = C3V3
Where:
C1 = concentration of the first solution (12.5%)
V1 = volume of the first solution (unknown)
C2 = concentration of the second solution (0% since it's distilled water)
V2 = volume of the second solution (unknown)
C3 = concentration of the final solution (10%)
V3 = volume of the final solution (2 oz or 59.15 mL)
Let's plug in the values and solve for V1:
(12.5%)(V1) + (0%)(V2) = (10%)(59.15 mL)
0.125V1 = 0.1(59.15 mL)
0.125V1 = 5.915 mL
V1 = (5.915 mL) / 0.125
V1 ≈ 47.32 mL
Therefore, you would need approximately 47.32 mL of the 12.5% solution and the remaining volume of the final solution (2 oz or 59.15 mL) would be filled with distilled water.