How much 7.5% Powerade stock solution (V1) do you need to make up 1mL (V2) of a 20mg/mL (C2) Powerade solution and how much water do you need

To solve this problem, we need to use the formula for dilution: C1V1 = C2V2, where C1 is the concentration of the initial solution, V1 is the volume of the initial solution, C2 is the concentration of the final solution, and V2 is the volume of the final solution.

First, we need to convert the percentage concentration of the Powerade stock solution to mg/mL. Since 7.5% means 7.5g/100mL, and knowing that 1g = 1000mg, we can say that 7.5g = 7500mg. Therefore, the concentration of the stock solution (C1) is 7500mg/100mL = 75mg/mL.

Now we can plug the values into the formula:

75mg/mL * V1 = 20mg/mL * 1mL

Solving for V1 gives:

V1 = (20mg/mL * 1mL) / 75mg/mL = 0.267mL

So, you need 0.267mL of the 7.5% Powerade stock solution.

To find out how much water you need, subtract the volume of the Powerade stock solution from the total volume:

1mL - 0.267mL = 0.733mL

So, you need 0.733mL of water to make up 1mL of a 20mg/mL Powerade solution.