What should this contain? j Count up how many iodine drops you have used, each one equals 10 seconds of reaction time. k Repeat the whole procedure with another of the pH buffers or pool your results with others in your class. l Collect repeat data if there is time. m Plot a graph of time taken for starch to break down against pH.
Rates of Reaction Lab - Concentration Name: _________________________________________ Date: ___________ Purpose: To determine how concentration affects the rate of a chemical reaction Materials: 100 ml graduated cylinder, 10 ml graduated cylinder, 100 ml beaker, 0.2M Na2S2O3, 3M HCl, water, stopwatch Procedure: 1. You will be completing 5 trials using the amounts in the table below. For each trial: Trial 1 2 3 4 5 Na2S2O3 10 ml 20 ml 30 ml 40 ml 50 ml Water 40 ml 30 ml 20 ml 10 ml 0 ml a. Use your 100 ml graduated cylinder to measure and add Na2S2O3 (aq), and H2O to the 100 ml beaker. b.
The 15 M NH4OH was added drop wise until a color change occurred, or until 20 drops were added. An additional 10 drops of 15 M NH4OH were then added to each solution. Again, 5 centrifuge tubes were labeled for the same 5 cations and 20 drops of each solution were added to the appropriate centrifuge. HCl was also added to a 50 mL beaker. The Nichrome wire loop was dipped in the HCl solution and placed over the Bunsen burner to disinfect it.
Taking the three solutions prepared earlier, each was transferred to three separate cuvette while filling the fourth cuvette was filled with distilled water. The spectrometer was first calibrated with the blank and then each solution was measured, collecting its spectrum line of every solution onto one chart. The data was then correctly labeled and saved onto a CSV file. Results and Discussion As seen in figure 1 of the absorbance spectrum, it was found that the yellow [HBB] had its highest absorbance rate at lower wavelengths which then quickly dropped to zero after it passed 480nm. On the other hand, the blue
The temperature was raised to 70 degrees Celsius and 4.419 g of salicylic acid was measured out on a balance and transferred into a 125. mL Erlenmeyer flask. Next, 8.00 mL of acetic anhydride was measured out and poured into the flask containing salicylic acid, ten drops of phosphoric acid was placed inside. The flask was then immersed into the hot water bath for twenty minutes. A vacuum filtration system was set up and the contents of the flask was transferred onto the filter paper. The mass of the filter paper and watch glass was 42.7131 grams.
A flame test was then conducted and the identity of the cation was determined. To determine the anion, the anion had to be separated first from the cation in the unknown compound. To do this, 0.1 grams of the unknown compound and 0.5 grams of sodium carbonate had to be boiled in 5 mL of distilled water. Once the solution boiled for 10 minutes, the precipitate was centrifuged out and the anion solution was left. 0.1 M silver nitrate was added to the anion solution and a precipitate was formed.
Temperature and pH are two environmental factors that will be used in the second part of the lab. One of the enzymes is denatured, meaning it was boiled for twenty minutes in hot water. The purpose of this experiment is to examine the specificity of the enzyme lactase to specific substrate lactose. Our group predicted that if lactase breaks down lactose then glucose and another sugar will be the end result for the first part. For the second part we
The enzyme then converts the substrate to the reaction products in a process that often requires several chemical steps, and may involve covalent bonds. Finally, the products are released into solution and the enzyme is ready to form another enzyme-substrate complex. As is true of any catalyst, the enzyme is not used up as it carries out the reaction, but it recycled over and over. One enzyme molecule can carry out thousands of reaction cycles every minute. Each enzyme is specific for a certain reaction because its amino acid sequence is unique and causes it to have a unique three-dimensional structure.
We weighed the resulting powder to be 3.228 grams. We then transferred the powder nutmeg into a 50 ml round bottom flask and added 15 ml of dichloromethane. We placed our flask in to a standard heat reflux apparatus and gently refluxed the mixture. We waited until we saw the first drip of liquid in the apparatus and heated for 15 minutes. After the mixture was heated, there was solid on the bottom and liquid on the top of the flask.
The pH recorded by using pH electrode before adding NaOH. The solution titrated by 2 ml of NaOH each time and the pH recorded until the color change. These steps were done for the two known solutions and the unknown solution. Part 2 10 ml of vinegar placed in 100ml volumetric flask and deionized water added until the mark. The solution transferred in 150 ml beaker labeled as beaker #1.