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
ions are colorless. The color of iodine can be more clearly seen with the addition of starch in which a dark blue-black complex will form. As long as there is iodine present in the reaction, some of the blue-black complex will be visible. When all the iodine has reacted with the ascorbic acid, the entire blue-black coloring will fade completely. This is the end-point of the reaction.
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
Also, both their Ph level was 7 which mean that they are neutral and not acidic and reaction with iodine solution was exactly the same. Therefore, with all the experiments conducted and analyzed, icing sugar is the mystery substance. c) Q: Which properties, physical or chemical, were most useful in identifying the mystery powder? Explain your answer.
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.
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
Table 2 represents the data compiled for unknown substances #6 and #7. When substance #6 was tested for the presence of protein, it did change color from blue to yellow, however this color change indicated a negative result. According to the results gathered in Table one, Part one of this lab, a color change from blue to light purple indicates a positive result; not blue to yellow. When Iodine
* If a stopwatch is used instead of a standard watch to time the 1 -
What effect will varying concentrations of pectinase, 0%, 1%, 1.5%, 2%, 2.5% and 3%, have on the rate of reaction, volume(cm3) and clarity of juice produced, of the apple (Malus domestica) variety of New Zealand Rose incubated at a temperature of 45C for 20 minutes?
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.
In this lab experiment, various solutions of different concentrations were created with Fe(NO3)3 (mL), KSCN (mL), and H2O (mL). When these chemicals were combined, a solution that was pale orange in color was created. These solutions were placed into a Colorimeter and their absorbance values were determined. Once these absorbance values were obtained, many calculations were done, including the Law of Mass Action (Keq = ([C]c x [D]d) / ([A]a x [B]b)) to determine the final answer of 159.7. This value is compared to the accepted Kc value of 133, revealing a percent error of around 20.08%.
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.
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,
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
This is the first reaction in the Harcourt Essen experiment. The iodine is oxidised to produce I2 wh...