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Calorimetry Lab

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1 ml of starch, 5 ml of 0.0200 M Na2S2O3 and 5 ml of a 0.5 M C2H3NaO2 buffer were put into a 100 ml graduated cylinder. Using a pipet, 2 ml of 0.250 M KI was added, and distilled water was poured into the graduated cylinder up to the 80 ml graduation. This solution was then transferred into a flask. Using a 50 ml burette, 20 ml of 0.100 M H2O2was added into this flask, and the mixture was briefly mixed. A chronometer was started and time until the solution turned blue was calculated and noted. The same experiment as above was repeated four times, but now by using 4 ml, 4.8 ml, 6 ml, and 8 ml of 0.250 M KI. Then, the experiment was repeated again four other times, but the volume of KI was kept constant at 8 ml. Water was added in the graduated cylinder up to the 95 ml, 90 ml, 88 ml and 85 ml graduation. The volume of H2O2 was changed respectively to 5 ml, 10 ml, 12 ml and 15 ml. …show more content…

Then, distilled water was poured up to the 80 ml graduation. After, the solution was transferred into a flask. This procedure was repeated two other times, with the same quantities. The three flasks were put into a large container filled with ice. A thermometer was put into one of the flasks. When the temperature of the solutions had reached about 3°c, 20 ml of 0.100 M H2O2 was added into one of the flasks. This flask was briefly shaken and put back in the ice. The chronometer was started. Next, the same amount of H2O2 was added into the two other flasks and the time at which this happened was noted. Then, the time until the solution turned blue was noted

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