Question

You are given 1.0 mL of the enzyme amylase and add cold 95% ethanol to reach a final concentration of 30% ethanol. What volume of the 95% ethanol did you need to add to the enzyme solution to obtain this concentration? (*note: this one is a little tricky—you will need to account for the starting volume of the enzyme solution.)

Answer 1

Let us assume x mL of cold 95% Ethanol is added to 1.0 mL of amylase enzyme.

So, final volume of the solution is (x+1.0) mL

From the data we get that

             0.95 * 1.0 = 0.30 * (x+1.0)

                     0.95 = 0.30 x + 0.30

                  0.30 x = 0.95 - 0.30

                     x = 0.65 / 0.30

                       = 2.16 mL

                           ~ 2.2 mL