Experiment 2: Preparation and Spectrophotometric Analysis of Copper(I) Iodide Abstract: This experiment aims to determine the concentration of “Purified CuI” sample. Crude CuI is obtained by reacting CuSO4.5H2O with KI and Na2S2O3 in de-ionized water. A series of decanting and centrifugation is carried out to extract the crude CuI. Crude CuI was later purified by dissolving it in hot KI solution. The solution was later transferred into de-ionized water and placed in an ice bath to allow for re-precipitation of “purified CuI” to settle. This is to ease the process of decanting and centrifugation carried out later. The concentration of “purified CuI” was determined by first diluting a solution of “purified CuI” twice, then carrying out UV-Vis …show more content…
2ml of 10% ammonium citrate was added to each beaker. The pH was then adjusted to 8.5 by adding 10 drops of 5M NH4OH(aq) to each beaker. 3ml of 0.1% cuprizone was added to each beaker. The four solutions were then transferred to 25ml volumetric flasks. The beakers were washed with de-ionized water, and the washings were combined with the solutions in the 25ml volumetric flask. De-ionized water was then added to make up the 25ml standard solution A to D. Spectrophotometric analysis was then carried out on the four standard solutions. The absorbance vaule at 600nm was recorded for each standard solution. These data were used to obtain the calibration …show more content…
Not enough time was given for the precipitate to settle in the beaker, hence when the supernatant is removed; there is a large amount of product lost. This is especially so in step 25, because a large amount of solvent is decanted. It will require much longer than the given time of 10 minutes to allow most of the precipitate to settle at the base of the beaker. Hence instead of decanting the mixture, centrifugation can be used to remove the solution instead. The amount of product lost will be significantly lower by carrying out this process. This is because when centrifugation is carried out, the precipitate will be clustered at the base of the centrifugation tube and when the supernatant is poured away, little to no precipitate would be lost. This can be known by seeing that the supernatant of the centrifuge tube after centrifugation is clear and there is a lack of suspension in the
Leave the boiling tubes for 1 hour to allow the precipitate formed to
The serial 2-fold dilution were done with a volumetric pipette, its pump, and 10 mL volumetric flasks. Eight different solutions were produced, half of which came from Red 40 and the other half, from Blue 1. These different concentrated solutions were placed in a 10 mL volumetric flask, each labelled with either R for Red 40
After copper ions were filtered, approximately 15mL of .5 M was added to the filtrate, which made the mixture acidic. Then, 20 mL was added into the filtrate to raise the pH of the mixture.
These difficulties might have caused me to make mistakes on the amount needed to pipette or the type of substance. Overall, next time I would have made sure to pay closer attention to the pipetting portion of the procedure. Furthermore, we could extend this experiment by trying different kinds of
In the experiment they used probes to test for pH, dissolved oxygen, total dissolved solids, conductivity, and turbidity. The probes hook up to the computer and collected the averages for each test. They collected this data and used it for later evaluation of the contaminates. They also tested for iron, copper, and chlorine with different tablets.
The heating of the solution caused the reaction to start which decomposed Cu(OH)2 and made the solution colorless and darkened the precipitate. The fourth step was the formation of CuSO4. After the solution was decanted from the precipitate and washed with near boiling water, 6 M H2SO4 was added to the beaker containing Copper (II) Oxide and this caused the precipitate to dissolve and the liquid become clear blue. The last step was the formation of Cu(s). This step recovered Solid elemental copper.
Abstract In this experiment the separation of a copper (II) chloride and sodium chloride mixiture was attempted. The main aim was to separate the compounds from eachother while receiving as much of the original mass of both substances as possible - in perfect conditions the original mass will be received after seperation. Many techniques were considered but dissolution, filtration and evaporation proved to be easiest and most reliable in a school environment with school equipment. The copper (II) chloride and sodium chloride mixture was dissolved in a methanol solution and filtered out leaving the sodium chloride behind.
3mL of the liquid in each of the vials were added into cuvettes and measured in the spectrophotometer. Before each time point the photo spectrometer was zeroed using a cuvette with 3mL of distilled water. If any of the results were considered unusual the machine was zeroed again and the sample was retested. The results from the spectrophotometer test were recorded in a table. The experiment was repeated six times to gain a sample size of six.
Purpose: The purpose of this lab is to titrate an unknown solid acid (KH2PO4) with a standardized sodium hydroxide solution. After recording and plotting the data, the acid’s equivalence point will be recorded once the color changes. Using the equivalence point, the halfway point will be calculated, which is used to determine the acid’s equilibrium constant. The acid’s calculated equilibrium constant will be compared with the acid’s established pKa value.
Conclusion: Based on the results of molarity from Trials 1, 2, and 3, it is concluded that our experimental for each trial is .410M NaOH, .410M NaOH, and .450M NaOH. The actual molarity of the NaOH concentration used was found to be 1.5M NaOH. The percent error of the results resulted in 72%. The large error may have occurred due to over titration of the NaOH, as the color of the solution in the flask was a darker pink in comparison for the needed faint pink. Discussion of Theory:
15) After each cuvette was tested, place the distilled water sample (Cuvette zero) to reset the spectrometer and to ensure that the scale is calibrated and repeat for each cuvette test. Data/Results: Tube Number Concentration Of CoCL2 (Mg/ML) CoCL2 Stock (ML) Distilled Water (ML) Spectrometry Reading at
Fractional distillation columns may contain a metal sponge, or have glass projections inside the column in order to increase the amount of surface area that the vapour comes into contact with. This causes some of the vapour to condense while in the fractional distillation column. Consequently, it falls back into the liquid reservoir. However, when this liquid to the reservoir, it contains a higher ratio of the more volatile substance than it did originally. This is repeated numerous times in the fractional distillation column and each time the liquid vapourizes, the vapour increases in purity.
Immediately 10 μL of double distilled water was added with a micropipette; this way our concentration of the treatment was the intended concentration.
Copper (Latin: cuprum) is an element with symbol Cu and atomic number of 29. Copper belong to a group called the transitional metal and is located on group 11 in the periodic table, possessing d-electron shells. It is a metal with high thermal and electrical conductivity. Copper can reach the oxidation state of -2, 0, +1, +2, +3, and +4, with +2 as the most common oxidation number of copper. Pure copper has a reddish-orange color, however, some observations suggested that copper in actuality has a yellow color.
Practical I: Acid-base equilibrium & pH of solutions Aims/Objectives: 1. To determine the pH range where the indicator changes colour. 2. To identify the suitable indicators for different titrations. 3.