Chemical Reaction's Observations and Analysis

Rates can be measured by determining the amount of the product formed per minute time. Our group observed the reaction . The ions in iodate ion (Solution A) and hydrogen sulfite ion (Solution B) are unable to be seen in the solution but the iodide ion formed by this reaction will react with the iodate ion. The reaction between iodine and starch form a dark blue starch/ iodine complex. If we use a constant amount of Solution B then we are able to interpret the rate from time for iodine to react with a set amount of Solution B. We are then able to interpret the effect of temperature on the reaction rate for the hydrogen sulfite ion to be used.

For the procedure our group used a clean 150 mL beaker to obtain 50 mL of solution A and a clean 100 mL beaker to obtain 50 mL of solution B. We poured 10 mL of each solution into separate test tubes and from there we added 3 drops of starch into the test tube containing solution B. Our group then poured the solutions together and we kept repeating it until a reaction occurred. When the reaction of the two solutions occurred, we recorded the exact time using the second hand. Our group repeated this process five times only changing one step each time. For the second repetition we placed both test tubes containing the solutions into a warm water bath for 5 minutes before mixing the two solutions again to record the reaction time. The third time, we put the test tubes in an ice bath for 5 minutes before proceeding to mix the solutions and record reaction time. For the fourth repetition we only used 9.0 mL of solution A and 1.0 mL of distilled water in one test tube and mixed it with the same test tube of solution B with 3 drops of starch and recorded the time it took for the solutions to react. The final repetition, we used a ratio of 8.0 mL of solution A and 2.0 mL of distilled water in one test tube and mixed it with the test tube containing solution B and 3 drops of starch and noted the time it took for the two solutions to react.

Repeating a set procedure five times under a different set of circumstances each time resulted in a different time for each reaction. The first reaction resulted in 28 seconds. The second reaction was a shorter time of 21seconds while the third reaction was our longest recorded result of 52 seconds. The fourth reaction took 37 seconds for the two solutions to react and the final reaction resulted in a time of 49 seconds for the solutions to react.

Based on our results, the times we recorded support the factors affect the rate of reactions in our notes. When the temperature increases, it increases kinetic energy making molecules move faster and the probability of a collision higher. Our second repetition of this lab supports this statement as seen when we placed both test tubes in warm water for five minutes and ended up having our shortest time of 21seconds. Our third repetition also supports how temperature affects rates of reactions as seen when we placed both test tubes in cold water for five minutes and ended up recording our longest time of 52 seconds. This proves that lowering the temperature will lower the rates of reaction. It is also stated in our notes that a lower concentration will decrease the rate of reaction. Our fourth and fifth repetition of the lab supports this as we put less of Solution A into the test tube resulting in times longer than our first attempt of the lab under standard conditions