What's the percentage of the H202 that has been consumed if you use 11.5ml

of water, 3.0ml buffer, 2.5ml KI, 1.0ml starch, 1.0ml Na2S203.and 1.0ml H202

To calculate the percentage of H202 consumed, you need to know the initial volume of H202 and the final volume of H202 after the reaction occurs.

Let's assume the initial volume of H202 is V1 ml and the final volume of H202 is V2 ml.

The total volume of the solution is the sum of all the volumes mentioned:
Total volume = 11.5 ml (water) + 3.0 ml (buffer) + 2.5 ml (KI) + 1.0 ml (starch) + 1.0 ml (Na2S203) + 1.0 ml (H202)

Now, to calculate V2 (final volume of H202), you need to consider the reaction that occurs between H202 and KI. In this reaction, H202 is converted to water and oxygen gas according to the following equation:

2H202 + 2KI + H2SO4 → 2H2O + 2KOH + I2

Since 2 moles of H202 react with 2 moles of KI, the volume of H202 decreases by a factor of 2. Therefore:

V2 = V1 - (1.0 ml of H202 * 2)

Now, you can calculate the percentage of H202 consumed:

Percentage consumed = ((V1 - V2) / V1) * 100

Plug in the values of V1 and V2 to get the answer.