If you are given a stock starch solution of 0.5 M, how much water will you add to produce 500 ml of 0.05 M solution?
To calculate the amount of water that needs to be added, we need to use the formula for dilution:
C1V1 = C2V2
Where:
C1 = concentration of the initial solution
V1 = volume of the initial solution
C2 = concentration of the final solution
V2 = volume of the final solution
Given:
C1 = 0.5 M
V1 = unknown
C2 = 0.05 M
V2 = 500 ml
By rearranging the equation, we can solve for V1:
V1 = (C2V2) / C1
V1 = (0.05 M * 500 ml) / 0.5 M
V1 = (0.025 mol/L * 0.5 L) / 0.5 mol/L
V1 = 0.025 L = 25 ml
Therefore, to prepare a 500 ml solution with a concentration of 0.05 M, you would need to add 25 ml of the stock starch solution and 475 ml of water.