Ascorbic Iodine Experiment

The titration worked well and yielded decent results. It was found that 72.10 mg of ascorbic acid is contained within a serving of lemonade.The %w/w of ascorbic acid is .30%. The volumes collected and observations made worked out to give proper and expected values. Rinsing the burette and pipette was important to this as it removed any water or dust inside. This meant that final volumes and calculations were more precise as there were fewer sources of error. The standard deviation obtained from the four trials was 0.22 mL. Much of this error is due to the rapid colour change. This made it difficult to precisely end the titration when the endpoint was reached. Another source of error is found in the assumption that because a colour change happened the proper reaction had occurred. This assumption while very basic and small potentially had a slight impact on final results. Titrations are very simple and therefore are empirical, and based off simple measurements with these simple assumptions accuracy decreases and error

To start off the experiment 25mL of water was placed into a labeled beaker and tested for the pH using pH test strips. Next the antacid tablet was placed in the solution and timed for how long it took to dissolve the tablet. Finally the temperature was measured. This same process was repeated for the acidic solution, and finally for the basic solution. After each experiment the pH, the reaction time, and the temperature of the beaker were recorded into a table. For this experiment the independent variable was the substance used (acid, neutral or base), and the dependent variable was the reaction time of each substance. The constant conditions of this experiment included the amount of substance being used, and the placing of one antacid tablet into each beaker. The experimental group was the acidic and basic solution, and the control group was the neutral

The experimental procedures for Lab 2 were provided on Blackboard labelled as “Pre-Lab 2: Techniques & Measurement”.

The purpose of this lab is to determine how the amount of vitamin C (ascorbic

At least three more titrations should be performed, this time more accurately, taking into account roughly where the end point will occur. The initial and final readings on the burette (prior to starting the titration and at the end point, respectively) should be recorded. Subtracting the initial volume from the final volume will yield the amount of titrant used to reach the

Test tube 8 had an initial colour of pale yellow and change to blue-black after the solution reacted with iodine. The result for test tube 8 was positive, proving that it had the presence of starch. Test tube 7 on the other hand, started off with a pale yellow colour and changed to dark brown. The result for test tube 7 was positive, showing that test tube 7 had glycogen content. Test tube 1,2,3,4,5,6 and 10 had negative results, having had no change at all.

1 ml of starch, 5 ml of 0.0200 M Na2S2O3 and 5 ml of a 0.5 M C2H3NaO2 buffer were put into a 100 ml graduated cylinder. Using a pipet, 2 ml of 0.250 M KI was added, and distilled water was poured into the graduated cylinder up to the 80 ml graduation. This solution was then transferred into a flask. Using a 50 ml burette, 20 ml of 0.100 M H2O2was added into this flask, and the mixture was briefly mixed. A chronometer was started and time until the solution turned blue was calculated and noted.

The purpose of this lab is to further explore kinetics by measuring the rate of reaction of iodide ionwith peroxydisulfate ion: Reaction 1 (slow). The second purpose is to determine the amount offormed over a certain time interval, orby titrating thewith the thiosulfate reaction 2 (fast) which quickly turns theback to the iodide ion. The third purpose of this lab is to determine the period of the clock the time it takes for reaction 2 to turn blue and go to completion “end point” by the reaction of iodine and starch. The final purpose is to calculate the rate law and collect data at several temperatures to determine the activation energy of the

Results: In this experiment, both baggies leaked out iodine into the starch. This was demonstrated when the starch surrounding the baggies turned dark purple. The color of the starch changed from white/grey into a darkish purple. When iodine mixes with a

Background research: Iodine is an indicator for cornstarch and will turn purplish-black when reacting with it. In this case iodine is the solute and cornstarch is a solvent. Diffusion is where molecules go from an area of low concentration to high concentration until molecules are evenly spread out. Plastic is semipermeable and iodine is smaller than the pores in plastic while cornstarch and water are bigger.

A dialysis bag, made from dialysis tubing and two strings, replaced the plastic sandwich bag. The bag sat in the solution for the majority of the two hour allotted class period. For the second procedure, it was performed as described on page thirty one and thirty two of the BIO 1120 laboratory manual. All samples were stirred every fifteen minutes, and measured after the forty five minutes were

1. What happened to the iodine solid in the water? Did it dissolve? Why do you

Determination of Vitamin C (Ascorbic acid) concentration in some of Commercial Products, by Redox Titration

Introduction: Titration is a technique used to find the concertation of an unknown acid, called the analyte, through the use of a base with a known concentration, called the titrant. In this experiment the analytes used were sulfuric and acetic acid and the titrant was sodium hydroxide. In order to find the concertation of these acids, the acid and base were mixed until they reached the equivalence point, or the point when the amount of titrant is equal to the amount of the analyte needed to fulfill the mole to mole ratio necessary complete neutralization. When the equivalence point was reached the phenolphthalein indicator made the solution turn light pink and this signified the endpoint of the acid-base titration. Before the titration of

For the second week, the experiment performed was done using Acid and base in place of water. 50ml of water was