Iodine Clock Reaction Lab Report

To catalyze a reaction, an enzyme will grab on (bind) to one or more reactant molecules. In this experiment we examined how increasing the volume of the extract added to the reaction would affect the rate of the reaction. The enzyme used was horseradish peroxidase which helps catalyze hydrogen peroxide. Using different pH levels, the absorbance rate of the reaction was measured to see at which condition the enzyme worked best. The rates of absorption were calculated using a spectrophotometer in 20 second intervals up to 120 seconds. It was hypothesized that the optimal pH for the enzyme was pH 7 while the 1.0 ml peroxidase would have the best reaction rate. At the end of the experiment the results prove the hypothesis to be incorrect.

The purpose of this experiment is to perform a two step reductive amination using o-vanillin with p-toluidine to synthesize an imine derivative. In this experiment, 0.386 g of o-vanillin and 0.276 g of p-toluidine were mixed into an Erlenmeyer flask. The o-vanillin turned from a green powder to orange layer as it mixed with p-toludine, which was originally a white solid. Ethanol was added as a solvent for this reaction. Sodium borohydride was added in slow portion as the reducing agent, dissolving the precipitate into a yellowish lime solution. Glacial acetic acid and acetic anhydride were added to the mixture while refluxing, which converted the lime colored solution into a clear mixture. The flask was cooled in an ice bath and the solution

They tested how the temperature would affect the rate of reaction. This was observed by the amount of time it took for the solution to change colors. For many chemical reactions there is an optimum temperature at which the chemicals will react with each other. As was found in their experiment, the temperature affected the rate of reaction. (Deoudes, 2010).

Reaction 2: when sodium hydroxide (NaOH) is added to copper (II) nitrate (Cu(NO3)2), a double displacement reaction will occur. Copper and sodium will displace each other to create copper (II) hydroxide and sodium nitrate.

With the timer ready, place one tablet into the cup of water. Immediately start the timer when the tablet comes in contact with the water. Stop the timer as soon as the reaction has stopped taking place and no remaining tablet is visible. Record the data.

(0.0035 moles of CaCl2) x (1 mole Ca(OH)2/ 1 mole of CaCl2) = 0.004 moles of Ca(OH)2

To determine the rate of reaction there are many method to be used for example, measuring the mass after the product has been added and measuring the difference in mass on the duration of a digital scale. Another method, which will be used in this experiment is using a gas syringe to measure the volume of the gas which has been produced. The cylinder inside, will be pushed out to show a quantitative presentation of the volume produced by the reaction.

Bio Chem lab Report 04 Enzyme Biochemistry Group Member: Chan Man Jeun Duncan (16002621) Law Sze Man (16000478) Introduction Enzyme is a protein base structure substance in our body. It works at a biocatalyst that will catalyzing the chemical reaction, which helps to speed up the chemical reaction. Enzyme could only function in specific shape, and the shape of enzyme is depending on the environment, therefore it is hard for an enzyme to function well in an extreme environment. The aim of this experiment is to see can the enzyme functions normally in different environment(pH, temperature and salt concentration) via using starch solution, amylase from saliva, 0.5M HCl solution, 0.5M NaOH solution and NaCl solution, and using iodine solution

The CO2 gas produced can be used as an indicator for the rate of reaction as the amount of CO2 gas that is collected with in a fixed time is proportional to the rate of reaction. Therefore, the average rate of reaction can be calculated by measuring the amount of CO2 collected for a set period of time.

Oxidant (oxidizing agent) is the element which reduces in experiment. Consequently, it induces second element to be oxidized.

The time taken for the bluish -black color to fade away (color of Iodine solution mix with starch solution ).

Predict/ roughly determine the Km by reading off of the graph the corresponding substrate concentration on the x-axis for the ½ Vmax value.

For the next 5 minutes, record the observed data at each minute (0, 1, 2, 3, 4, 5)

The end of the reaction, will be determined by observing color change of solution. Thus, solution should shange color to blue. Blue color appear because of starch indicator. Starch indicator reveals the blue color due to the presence of I2. During the reaction iodine reacts with thiosulfate at the beginning:

The goal of the experiment is to examine how the rate of reaction between Hydrochloric acid and Sodium thiosulphate is affected by altering the concentrations. The concentration of Sodium thiosulfate will be altered by adding deionised water and decreasing the amount of Sodium thiosulphate. Once the Sodium thiosulphate has been tested several times. The effect of concentration on the rate of reaction can be examined in this experiment.