Catalysts

2396 Words 10 Pages
I. Introduction
Catalysts are stimulus that speed up the rate of a reaction by lowering the activation energy of the reaction. Chemists discovered catalysts when they were trying to determine how to turn one substance into another. Although early chemists did not resolve how to turn substances into one another, they did discover that various materials could be changed from one form to another. This also led to the discovery that if certain chemicals were present in the reaction, the change would occur faster without consuming itself in the reaction. It is important to acknowledge that a reaction cannot be catalyzed that wouldn’t already occur in the absence of a catalyst. The reaction being catalyzed occurs naturally and does not depend on
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Tube 1 consisted of 1 mL enzyme solution, 2 mL catechol, and 2 mL of the chelating agent EDTA. Tubes 2 and 3 had the same contents except Tube 2 had 2 mL of the chelating agent PTU and Tube 3 had 2 mL of the chelating agent citric acid, rather than EDTA like Tube 1. Tube 4 was used as our control and consisted of 1 mL enzyme solution, 2 mL catechol, and 2 mL . This was our control because it uses distilled water rather than a chelating agent, showing how a reaction would occur normally without a chelating agent present. Our calibration tube (Tube 5) was 5 mL of . The calibration tube was not used as a control, but rather to establish a minimum value of absorbency. A pipette was used to pour the contents into a vial, which provided better accuracy in measuring the tube contents. It is important to acknowledge that the catechol solution was not added to the solution until 10 minutes later so that the chelating agents would have time to bind with the cofactor. During this 10 minutes, the tubes were covered with parafilm and were inverted to mix the contents of the tube every 2 minutes. The sides of the tubes were wiped with Kimwipes to keep the tubes as clean as possible for accurate readings from the spectrophotometer. Once the 10 minutes passed, 2 mL of catechol solution was added to Tubes 1-4. We then calibrated the spectrophotometer to a value of 0 …show more content…
Tube 1 contained the chelating agent EDTA, which can bind to both calcium and magnesium ions. This tube had the highest change in absorbance, meaning that the presence of this chelating agent did not affect the speed of the reaction since the cofactors were not bound up. We can conclude from this data that the reaction was not inhibited and could occur normally, allowing a high change in absorbance, color change, and formation of product. Tube 4, which was our control tube, also supports this idea. The control solution did not contain a chelating agent, meaning that this tube was measuring how a reaction would occur without a chelating agent present. Because there was no chelating agent for a cofactor to bind to, the reaction occurred normally and had a positive change in absorbance and a prominent color change. However, the control’s change in absorbance was not as high as Tube 1, which is due to the fact that the cofactor in Tube 1 was readily available to help the enzyme speed up the

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