3 Agar Cubes Containing Ph-Indicator Dye Phenolphthalein

At five minute intervals over the next fifteen minute period, record the color intensity of the solution of each test tube.

And finally into test tube 3, I pipetted 1.0 ml turnip extract and 4.0 ml of water. The contents of test tube 1 was poured into a spectrometer tube and labeled it “B” for blank. “B” tube was now inserted it into the spectrometer. An adjustment to the control knob was made to zero the absorbance reading on the spectrometer since one cannot continue the experiment if the spectrometer is not zeroed. A combination of two people and a stop watch was now needed to not only record the time of the reaction, but to mix the reagents in a precise and accurate manner. As my partner recorded the time, I quickly poured tube 3 into tube 2. I then poured tube 2 into the experiment spectrometer tube labeled “E” and inserted it into the spectrometer. A partner then recorded the absorbance reading for every 20 seconds for a total of 120 seconds. After the experiment, a brown color in the tube should be observed to indicate the reaction was carried out. Using sterile techniques, any excess liquid left was disposed

You know what color phenolphthalein and BTB turn when testing an acid or a base. Use three household cleaning products with BTB. Name the items tested and their results:

The null hypothesis will be that the test tubes with an increase in temperature, pH values, enzyme concentrations, and substrate concentration will have a very small color change or no color change at all. The alternate hypothesis is that the test tubes containing an increase in temperature, pH values, enzyme concentrations, and substrate concentration will all have an intense color change; the more the change, the more intense the color change will be.

Students will place a potato cube into a test tube and add 3 ml of H202 into each tube. Then students will wait one minute and record the height in cm of the bubbles and rate how rapidly the solution bubbles on a scale of 0-5. (0=no reaction, 1=slow,……. 5= very fast.)

To conclude, the data we have collected from both experiments suggests that Le Chatelier’s principles are applicable and correct. When different substances were added to different solutions, the equilibrium shifted appropriately in order to gain a balance. The shifting of equilibrium resulted in different color changes in different mixtures. In part 2 of the experiment we the aforementioned changes were more easily spotted. We saw the relationship between forward and reverse reactions. When NaOH was added to tube #8 we saw that the color changed from orange into yellow, in order to gain balance but when we added HCl back, the color again changed to orange. Which clearly proved Le Chatelier’s

Lab six requires students to observe the effects of pH and enzyme concentration on catecholase activity. Enzymes are organic catalysts that can affect the rate of a chemical reaction depending on the pH level and the concentration of the enzyme. As pH comes closer to a neutral pH the enzyme is at its greatest effectiveness. Also at the absorbance of a slope of 0.0122 the enzyme is affected greatly. The pH effect on enzymes can be tested by trying each pH level with a pH buffer of the same pH as labeled as the test tube and 1mL of potato juice, water, and catechol. This is all mixed together and put in the spectrophotometer to test how much is being absorbed at 420nm. As the effect on enzyme concentration can be tested almost the same way. This part of the exercise uses different amounts of pH 7-phosphate buffer and potato juice, and 1mL of catechol mixed together in a test tube. Each substance is put in the spectrophotometer at a wavelength set tot 420nm. The results are put down for every minute up to six minutes to see how enzyme concentration affects reaction rate. The results show that the pH 8 (0.494) affects the enzyme more than a pH of 4 (0.249), 6 (0.371), 7 (0.456), and 10 (0.126). Also the absorbance is greatest at a slope of 0.0122 with test tube C that has more effect on the reaction rate, than test tube A, B, and D.

6. In 1 minute intervals, we observed the color changes of the reactions and compared them to the color palette. We did this for 5 minutes.

Our purpose in this lab was to create four solutions of the same components and different concentration. I found the concentration in Molarity (mol/liter). I would dilute a solution to create new solutions, using the formula M1xV1=M2xV2 where M=molarity and V=volume. In this lab, there were four solutions, Solution A, Solution B, Solution C, and Solution D. The solute or substance that dissolves was sugar and the solvent or substance that the solute dissolves in was water. For Solution A, I weighed 3.42 g sugar and diluted to 100 mL to get a concentration of 0.10 M and the color of bright red. For Solution B, I weighed 0.342 g sugar and diluted to 100 mL to get a concentration of 0.010 M and the color of pink. For Solution C, I measured 10

The research question for the Alka Seltzer Lab is, “What is the effect of different surface areas of an Alka Seltzer tablets reaction time?’. Inside of an Alka Seltzer tablet there are two key ingredients; which are citric acid and baking soda. When a tablet is dropped into a liquid, the acid and baking soda show a physical reaction of fizzing and eventually dissolving. Materials needed for this lab was goggles, aprons, beakers, water of the same temperature, mortar pestle, and three alka seltzer tablets. In each beaker there was 150 mL of water. The first tablet was a full tablet, the second was broken into quarters, and the last tablet was crushed in a mortar pestle. The dependent variable of the lab was the rate of reaction, and the independent

Next, add enough bromothymol blue solution to each test tube until the water is blue. Next, using a straw, blow into the four test tubes until the color blue turns to the color of a yellowish/green. Then cut a sprig of Elodea from the plant and place one sprig into each of the four test tubes. Then the test tubes were sealed with a stopper. Two of the test tubes will be labeled light and placed into sunlight for about 2 hours. Then the other two test tubes will be placed into complete darkness for about 2 hours. After time is up, record the color of the solution from the four test tubes (Gunstream,

Add 4 drops of phenolphthalein in to the prepared acetic acid, and check whether the color changes to dark pink.

In this experiment, I wanted to determine the effect that basic or alkaline solutions have on the enzyme, polyphenol oxidase that is found in apples. Given the idea that acidic solutions reduce the reaction rate of this enzyme, I conducted this experiment to see if alkaline solutions do the opposite and instead increase the reaction rate. With this in mind, the experiment was executed using two basic solutions to increase the credibility of the results which proved that alkaline solutions increase the reaction rate. I was able to determine this by comparing the apples that were treated with the control group, from this I understood that both the untreated and treated apples had a similar reaction rate. Though all of the apples had some brown

Then, each group of students received the necessary materials to complete the experiment. When the students received the cups, they labeled cups to distinguish between the salt solution, distilled water, and control group. After weighing the cups and finding the mass of the cucumbers, the students poured 50 ml of water in one cup, 50 ml of salt solution in the other, and left the control cup empty. Then, the students placed the cucumbers into the cups and waited 30 minutes for the results. After the 30 minutes, the students removed the cucumbers from each solution and dried the cucumbers with paper towels. The students then weighed the cucumbers again and recorded their results. Lastly, the students found the difference from the original mass of the cucumbers and recorded their results.

In this lab a acid-base indicator phenolphthalein was used to determine endpoint of a reaction HCl(aq) and KOH(aq). At the end point all of the HCl(aq) would have reacted with KOH(aq), and the pH becomes 7. The phenolphthalein would changed colours from colourless to pink indication when enough KOH(aq) was added. The purpose of numerous trials was to use the average volume of the 3 trials with similar measurements.