Forming Hydrogen Idodide

Experiment #2

The purpose of this lab is to study reaction rates using hydrogen and iodine to form hydrogen iodide. As HI increases, the concentration of H2 and I2 decrease. In this experiment we observed what happens to the reaction rate when the concentration of reactants differs. We observed a chemical change watching iodine change from a yellow to colorless solution. We set up four experiments with varying concentrations of acetone, water, acid, and iodine.

Reaction number one had the greatest volume of water. This was our experimental control. It’s time was 237 s. Reaction two had the greatest volume of acetone. This reaction took about half the time as the control to neutralize the iodine. It’s time was 84 s. Our measured rate was a little slow. I think our concentration measurement was slightly over what it should have been which slowed our reaction time. Reaction three had the greatest volume of acid. Its rate was very similar to reaction three, the acetone. The time was 105 s. This tells me that the acid is a great catalyst between acetone and iodine. Reaction four increased the amount of iodine which slowed the reaction rate significantly because there was more iodine to neutralize. The reaction time was 428 s.

We then calculated our initial concentrations to come up with an initial reaction rate of Iodine per second. Next we used this data to calculate reaction orders. We found that acetone and acid are first order reactions. They exponentially influence the reaction rate. Then we calculated the rate constant, k and averaged it to 2.8 x 10-5. Finally, we have our determined rate equation which is rate = 2.8 x 10-5 [aceteone]1[iodine]0[acid]1.