Chemical Reaction Lab

The purpose of the experiment was to determine how a buffer works and how to use an acid-base indicator. The way a buffer works was determined by observing the changes in pH of solutions of different concentrations weak acids and their conjugate bases to determine how a buffer affects the pH change. The solution of 10 mL of 0.20 M CH3COOH and 10 mL of 0.20 M CH3COONa had slighter changes in pH than the solution of 10 mL of 0.0020 M CH3COOH and 10 mL of 0.0020 M CH3COONa. Both of these solutions were buffers, shown because they had slighter changes in pH than the solutions with only the weak acid or conjugate base and water. The determination of how buffers work was also tested with observing that the solution of NaC4H3O4 and Na2C4H2O4 had smaller

Catalase is an enzyme needed to break down hazardous hydrogen peroxide into nonhazardous oxygen and water. This is needed for organisms as the reaction rate of the decomposition of hydrogen peroxide is too slow to protect cells against the oxidation of hydrogen peroxide. The purpose of this experiment is to test the concentration of hydrogen peroxide on catalase and variation in temperature of catalase to find the optimal values that will produce the highest rate of products. It was hypothesized that as the concentration of substrates increases, the reaction rate will as well. The null hypothesis for this is that the substrate concentration will have no effect on the reaction rate. For the varying temperature of catalase, it was hypothesized that as the temperature increases, the reaction rate will increase as well until the enzyme is denatured. The null hypothesis for this is that varying temperature will have no effect on the reaction rate. The experiment was completed by using a 10mL graduated cylinder filled with water that collected oxygen gas that was produced by the reaction. From this experiment, one can see that as the amount of hydrogen peroxide concentration increases, the rate of the reaction increases as well. The results support this as the average reaction rate starts at 0.00 mL O2/min for 0.0% hydrogen peroxide and raises to 38.17 mL O2/min for 0.8% hydrogen peroxide. As the temperature of catalase was increased, rate of reaction continued to

Objective: Measure the rate of decomposition of hydrogen peroxide with and without the addition of an enzyme catalase at different time intervals.

Procedure Part 1: Observe Normal Catalase Reaction Place a potato cube (3x3x3 cm) into a test tube Add 3 mL of H2O2 into each test tube Allow 1 minute for reaction to occur Record the height in cm of the bubbles Rate how rapidly the solution bubbles on a scale of 0-5 (0=no reaction, 1=slow,...5 =very fast) Part 2: Effect of Temperature on Enzyme Activity Label 3 test tubes: hot, cold, and room temperature Place potato cube (3x3x3 cm) into each test tube Place the test tube labeled hot and cold into the coordinating baths Place the test tube labeled room temperature into the test tube labeled room temperature on the test tube rack Level each test tube in place for 3 minutes After 3 minutes record the temperature of each tube Add 3 mL of H2O2 into each tube After a minute, record the height in cm of the bubbles in each tube Rate how rapidly the solution bubbles on a scale of 0-5 Part 3: Effect of pH of Enzyme Activity Label 3 test tubes acid, base, and pH 7 Place 3 mL of potato catalase into each tube Add 10 drops of vinegar to the test tube labeled acid Add 10 drops of ammonia into the tube labeled base Add 10 drops of distilled water into the tube labeled pH 7 After 2 minutes add 3 mL of H2O2 to each

In part II of the lab six small glass tubes were obtained in a test tube rack. Ten drops of distilled water were then added to test tube 1, five drops to tubes 2-4, and no drops in tubes 5 and 6. Five drops of 0.1M HCl were added to test tube 5 and five drops of 0.1M NaOH to test tube 6. Five drops of enzyme were then added to all tubes except tube 1. Tube 3 was then placed in the ice bucket and tube 4 was placed in the hot bucket at 80-900C for five minutes, the remaining tubes were left in the test tube rack. After the five minutes five drops of 1% starch was added to every tube and left to sit for ten minutes. After ten minutes five drops of DNSA were then added to all the tubes. All the tubes were then taken and placed in the

In this above reaction, oxygen is released and is used for other cellular purposes, but when it occurs in a test tube, similar to this experiment, the oxygen gas bubbles producing a layer of foam on the surface of the peroxide. The amount of foam and the speed it is produced are forms of measuring the catalase activity. In the next experiments, one would determine the degree of catalase action by calculating the thickness of the foam layer. It is hypothesized that when reacting with: potato, apple, steak, or liver, the plants and animal tissues will react differently.

Experiment 4: Effect of PH Add buffers of various pH values to your enzyme and let them sit prior to adding the hydrogen peroxide. Mark three test tubes each at the 1 cm level, 3 cm, and 7 cm levels and fill each tube to the first mark with potato juice and shake it. Then for the second mark with either pH 3, pH 7, and pH 11 buffer. Let it sit for five minutes and add hydrogen peroxide to the 7-cm mark, swirl, wait 1 minute and take

The purpose of this experiment is to see how the enzyme peroxidase performs under different conditions. An enzyme is a protein molecule that is a biological catalyst. A catalyst is a substance that speeds up a chemical reaction, while also lowering the activation energy of a reaction. The activation energy of a reaction is the initial amount of energy that is necessary to bring reactants together with the proper amount of energy and placement so that products can be formed. Enzymes have a unique 3-D shape, which enables it to stabilize a temporary association between substrates (the reactant molecules that binds to the active site of an enzyme and undergoes chemical modification).

We measured 3 mL. of catalase into eight test tubes because to us, it was the right amount to place into a test tube, without having any overspills. For two test tubes, we added 9 mL. of vinegar and 9 mL. of Hydrochloric Acid (HCL) to another pair of test tubes because this amount was reasonable for not being too much that it overpowers the catalase and not too little that we may not see any impact. Now, we repeat the same process of adding hydrogen peroxide (H2O2) and sodium hydroxide (base solution) to the rest of the pairs of test tubes with catalase. Our group then analyzed each pair's appearance and its amount of foam. Thus, we can compare it to later results from the second experiment that would be conducted as the following. Afterwards, our group individually takes one tube from each pair, containing the same base or acid, and put it into a beaker filled halfway with ice for two to three minutes. We believed this amount of time was the most efficient for us to be able to finish the lab and collection of data. At the same

Part A: Add a small piece of liver to 2 ml of 3% hydrogen peroxide solution. After the reaction occurs, pour the liquid into a different test tube and add another piece of liver into the liquid. Observe the reaction. Then add 2 ml of hydrogen peroxide to the first test tube.

In tube 4, instead of a cube of liver, ground liver was added. Nevertheless, the results did not differ much from tube 3, which indicates that catalase in ground liver breaks down hydrogen peroxide at the same rate as in a cube of liver. However, the temperature of the H2O2 increased from 26 degrees Celsius to 37 degrees Celsius after the addition of liver.

When the results of the experiment were obtained and documented, the possibility of an error in testing was first thought. As testing results were reviewed further, it was found that the experiment of test tube number four was performed exactly the same way as the first three test tubes. The experiment was also performed keeping in mind to avoid contact with other heat sources, proper insertion of the O2 probe, and proper operation of the Lab Quest regarding proper setting of time of experiment, making sure to wait thirty seconds before starting the Lab quest timer, and proper documentation of the graph. To fully understand enzymes, we must first understand how enzymes work. Enzymes speed up a cell’s chemical reactions by lowering energy barriers.

This lab will observe the conversion of hydrogen peroxide to water and oxygen gas by the enzyme catalysis. The amount of oxygen generated will be measured and used to calculate the rate of the enzyme-catalyzed reaction. Enzymes are proteins produced by living cells. Enzymes act as biochemical catalysts during a reaction, meaning they lower the activation energy needed for that reaction to occur. Through enzyme activity, cells gain the ability to carry out complex chemical activities at relatively low temperatures. The substance in an enzyme-catalyzed reaction that is to be acted upon is the substrate, which comes together reversibly to the active site of the enzyme. The active site is the portion of the enzyme that interacts with the substrate. One result of this temporary union between the substrate and the active site is a reduction in the activation energy required to start the reaction of the substrate molecule so that products are formed. In a mathematical equation of the substrate (S) binding with the activation site (E) and forming products (P) is:

In this experiment peroxidase, the enzyme that uses Hydrogen peroxide and produces H2O and O2, will be used (Carnal et al., 2015). As Campbell et al. (2009) stated, the experiment will test what environment like concentration, pH, and temperature would affect enzyme reactions. For the first experiment, reaction rates at different concentrations of peroxidase will be measured using spectrophotometer, test tubes, Guaiacol dye. Test tubes with substrates and buffer will be mixed and the change will be recorede by 20 seconds for 6 times.

Moreover, during the storage period, the pH values of the control samples increased, whereas the pH values for the other treatments initially decreased and then eventually increased. Other researchers reported the same results (Alasalvar et al., 2001; Manju et al., 2007). The decline may be due to acetic acid used in solution was prepared samples, Celis et al., (2011). However, increase in pH can be caused by the increase in the production of alkaline substances, such as ammonia compounds which is caused by the action of internal or microbial enzymes, and eventually leads to decomposition of proteins ( Huss et al., 2000, Fan et al., 2009).