This experiment will determine the levels of Vitamin C present in each of the different fruit juices selected. The level of Vitamin C will be compared between each fruit juice to determine which one has the highest amount of Vitamin C. Several drops from one fruit juice will be mixed into an iodine solution then repeated with a different fruit juice. With every drop of fruit juice a chemical reaction occurs and the process continues until the solution becomes colorless. The reaction will vary in according to the amount of Vitamin C present in each one of the different fruit juices.
Dehydroascorbic acid and iodide ions are produced when ascorbic acid and iodine solution are mixed. Iodine has a brown color in solution whereas iodide
Then, an amount of KI (solid) about a size that would fit on a match head was dissolved in 0.05 of Potassium Iodate solution and about 1 mL of water and 1 mL of 1 M HCl were added, which exhibited a weak positive test for IO_3^- (aq). After the weak positive test, an amount of KI (solid) about a size that would fit on a match head was dissolved in about 1 mL of water and 1 mL of 1 M HCl, which exhibited a negative
A: The reaction with water and vinegar was the most useful in this experiment. The physical properties were very self explanatory because the texture of the powders was all different expect icing sugar and cornstarch. Also the Ph levels were very similar of six and seven for corn starch and icing sugar respectively. d) Q: How confident do you feel about your identification of the
The weight of the final product was 0.979 grams. A nucleophile is an atom or molecule that wants to donate a pair of electrons. An electrophile is an atom or molecule that wants to accept a pair of electrons. In this reaction, the carboxylic acid (m-Toluic acid), is converted into an acyl chlorosulfite intermediate. The chlorosulfite intermediate reacts with a HCL. This yields an acid chloride (m-Toluyl chloride). Then diethylamine reacts with the acid chloride and this yields N,N-Diethyl-m-Toluamide.
To uncover organic compounds like carbohydrates, lipids, proteins and nucleic acid, by using tests like Benedict, Lugol, Biuret and Beta Carotene. Each test was used to determine the presents of different organic molecules in substances. The substances that were tested for in each unknown sample were sugars, starches, fats, and oils. Moreover, carbohydrates are divided into two categories, simple and complex sugars. Additionally, for nonreducing sugars, according to Stanley R. Benedict, the bond is broken only by high heat to make make the molecules have a free aldehydes (Benedict). As for Lipids, there are two categories saturated and unsaturated fats. One of the difference is that saturated fats are mostly solids and have no double bond (Campbell Biology 73). The Beta Carotene test works by dissolving in a lipid, thus giving it color to make it visible. Moreover, proteins are made out of amino acids that are linked by a polypeptide bond (Campbell Biology 75). The purpose of this experiment was to determine whether an unknown class sample or food sample had any carbohydrates, lipids, or proteins in it. The expected result of the lab was that some substances would be present while other would be absent.
Iodine turns into a blue/black color when in the presence of starch, after using iodine if the blue/black color is absent then the starch has been used usually making a halo around the inoculum, resulting in a positive result. If it stays blue/black then the starch is still present meaning the organism cannot produce amylase causing a negative result. My color stayed blue/black and there was no evidence of a halo, meaning my organism is negative for producing amylase. (handout, amylase)
This figure is slightly higher than its actual value, which should be approximately 81%. This was obtained as a result of finding the atomic mass of iodine. The atomic mass of the iodine was then multiplied by 4 as there were 4 atoms of iodine in tin(IV) iodide. This was then placed over the molecular mass of tin(IV) iodide and multiplied by 100 to be expressed as a percentage. This value could have been more accurate to its real value (i.e. approximately 81%) if the titration had been stopped as soon as the solution went yellow. At this point, the final colour of the solution is yellow due to the fact that some ICl2- (iodine dichloride) formed. This compound is formed from the reaction of iodine monochloride (ICl) with excess hydrochloric acid (HCl). In the preparation of the tin(IV) iodide, the crude % yield was found to be 61.02596306%. This yield could have been higher if the mixture in the round-bottomed flask was allowed to reflux for a longer time period. In addition to this, the crude yield could have been higher if the tinfoil was cut up into smaller pieces. This would have meant more surface area exposed to the mixture of iodine, acetic anhydride and glacial acetic acid. More surface area means more molecules have more space to react with the solution. This also means that the reaction would have occurred at a much
Observations: Solution of ethanol and spinach leaves was light greenish in color. I shone a blue laser pen light on the cuvette and saw a red-pinkish light.
* If a stopwatch is used instead of a standard watch to time the 1 -
In our Biology Lab we did a laboratory experiment on fermentation, alcohol fermentation to be exact. Alcohol fermentation is a type of fermentation that produces the alcohol ethanol and CO2. In the experiment we estimated the rate of alcohol fermentation by measuring the rate of CO2 production. Both glycolysis and fermentation consist of a series of chemical reactions, each of which is catalyzed by a specific enzyme. Two of the tables substituted some of the solution glucose for two different types of solutions. They are as followed, Table #5 substituted glucose for sucrose and Table #6 substituted the glucose for pH4. The equation for alcohol fermentation consists of 6 Carbons 12 Hydrogens 6 Oxygen to produce 2 pyruvates plus 2 ATP then finally the final reaction will be 2 CO2 plus Ethanol. In the class our controlled numbers were at Table #1; their table had 15 mL Glucose, 10 mL RO water, and 10 mL of yeast which then they placed in an incubator at 37 degrees Celsius. We each then measured our own table’s fermentation flasks every 15 mins for an hour to compare to Table #1’s controlled numbers. At
Reaction 2 6H+ + IO3- + 8I- 3I3- + 3H2O this may occur during the reaction or once the bisulphate has been consumed. But there’s another reaction which takes place, Reaction 3 H2O + I3- + HSO3- 3I- + SO42- +3H+. Where the iodate ions react to form tri-iodide ions to iodide and the water and iodate form sulphate. Now the starch solution reacts with the Iodide to form the dark blue solution. Landolt Clock Reaction equations given on the site (Lyle,
However, in order to measure the rates of reaction, sodium thiosulphate and starch are added. Sodium thiosulphate is added to react with a certain amount of iodine as it is made. Without the thiosulphate, the solution would turn blue/black immediately, due to the iodine and starch. The thiosulphate ions allow the rate of reaction to be determined by delaying the reaction so that it is practical to measure the time it takes for the iodine to react with the thiosulphate. After the all the thiosulphate has reacted with the iodine, the free iodine displays a dark blue/black colour with the starch. If t is the time for the blue/black colour to appear, then 1/t is a measure of the initial rate.
In this experiment I will be finding out which fruit juice contains the most vitamin C. I will be using a method similar to titration but I will be using a syringe instead of a burette.
This is the first reaction in the Harcourt Essen experiment. The iodine is oxidised to produce I2 wh...
The two major properties of vitamin C which make it an ideal antioxidant: First is the low one-electron reduction potentials of both ascorbate (282 mV) and its one-electron oxidation product, the ascorbyl radical (2174 mV) which is derived from the ene-diol functional group in the molecule. These low reduction potentials enable ascorbate and the ascorbyl radical to react with and reduce basically all physiologically relevant radicals and oxidants. For this reason, vitamin C has been said to be “at the bottom of the pecking order” (Carr and Frei, 1999). The second major property that makes vitamin C such an effective antioxidant is the stability of semidehydro-ascorbic acid or ascorbyl free radical(ASF) ,the species formed after the loss of one electron, with a half-life of 10−5 seconds and low reactivity of them (Carr and Frei, 1999;Packer, 2002; Padayatty et al., 2003).Once oxidized, ascorbate is turned into ascorbate free radical (AFR) a molecule that is relatively stable due to electron delocalization. Although AFR can donate another electron, it does not undergo further oxidation. Rather, it is reduced back to ascorbate via NADH-dependent
vi. One possible improvement could have been to add an extra part to the investigation, involving the formation of a calcium citrate precipitate from the citric acid in the lemon juice (using limewater of a known molarity), which could be extracted and weighed: