Determination of Cu2+ by Titration
Introduction:
The purpose of this lab is to determine the concentration of copper ions in an unknown solution. Complexometric titration will be used to determine the concentration. A buret will be used to deliver the complexing agent to the unknown solution. Ethylenediaminetetraacetic acid will be used as the complexing reagent. An indicator, Murexide in our case, will be used to indicate the endpoint of the reaction.
Theories and Concepts:
The anion of the acid, EDTA4-, will complex to the metal. This anion reacts with the metal by forming coordinate-covalent bonds with the metal. This is a coordination compound. This ligand is called a chelate because it can form coordinate-covalent bonds by wrapping itself around the metal. A total of six coordinate covalent bonds are formed between the copper cation and the ligand. The Murexide indicator will mix with the blue copper solution to form a compound that is purple. As soon as an exact amount of the ligand is titrated and binded to all of the metal in the solution the color of the soluti...
Put 1mL of 0.1M cobalt (II) chloride hexahydrate dissolved in 95% ethanol into a test tube. Then add 1mL of deionized water. Tap the end of the test tube to mix the solution and record the pertinent data in section 2 of the Data Table. Discard the solution in the appropriate container as directed to you by your lab instructor.
The color that was chose to be shined through the sample was purple. The spectrophotometer was set at a wavelength of 400nm to represent the purple color. It was zeroed using the blank meaning the spectrophotometer read zero as absorbance amount. The blank consisted of 5mL of water and 2.5 mL AVM and it was placed in cuvette. A solution with a known concentration of 2.0x10-4 M was used in the spectrometer. For this solution, 5 mL of the solution with 2.5 mL of AMV was placed in the cuvette. The cuvette was placed inside of spectrophotometer and the amount of absorbance was recorded. This procedure that involves a solution with a known concentration was repeated for the concentrations:1.0x10-4 M,5.0x10-5 M,2.0x10-5M, and1.0x10-5M.A unknown solution absorbance was measured by putting 5 mL of unknown solution with 2.5 mL AMV in a cuvette. The cuvette was placed in the spectrophotometer and the amount of absorbance was recorded. The procedure that deals with the unknown solution was repeated 2 more times with the same solution and the same amount of solution and AMV. The average of the three unknown solution was calculated and the concentration of the unknown solution was
To complete this lab several chemicals must be measured and transferred to test tubes. First 5.0 mL of 0.200 M Fe(NO3)3 must be diluted to a total volume of 50 mL in a flask. Next 0.0020 M SCN–. This solution is then added to 4 test tubes in 1 mm increments. Each test tube is then put in to
The objective of this lab was to calculate the ratio of the copper sulfur compound to conclude whether the compound is made of copper I or II.
In the first part of this project, two cation elimination tests and one cation confirmation test were performed. 10 drops of 4 cation solutions: potassium, zinc(II), copper(II)
If more than one complex is formed at different pH values, their existence can be decided by this type of study. The pH, at which the absorption due to a particular complex species is far greater than that of metal ion and or the ligand alone, is selected for the study of that species. As the complex formation is the function of pH; it should be kept constant for particular system. Similarly, ionic strength is maintained constant throughout by adding an appropriate volume of sodium perchlorate. pH can be remained constant by using suitable buffer, provided the buffer does not interfere with the complex formation at wavelength where complex species show maximum
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
The compound that was assigned to be tested and the identity to be discovered was blue in color. Once 0.5028 grams of the blue compound was weighed out it was combined with 5 mL of distilled water. initially the unknown compound didn’t seem to dissolve in water. However, after a few minutes of constant stirring the substance dissolved completely. Thus indicating that the cation in the unknown compound was Cu2+. The identity of the cation had to be confirmed therefore a flame test had to be preformed. Once the solution was placed over the Bunsen burner the flame turned green confirming that the cation was Cu2+. To determine the character of the anion 0.1087 grams of the unknown compound, and 0.5109 grams of Na2CO3 was measured. Both solids were
As 10 mL of NaOH was added drop wise, the solution began to have a pink tint. The fuchsia color did not permanently stay until 9mL of NaOH was added. The pH indicator demonstrated when exactly the reaction has neutralized. Because an acid and a base reacted to form water and a salt, the reaction is a neutralization
Read the initial buret readings for both burets to the nearest 0.01 ml. Use a buret reading card to make the meniscus more prominent. Record readings on the report sheet. Have your instructor check and initial your report sheet for your first buret reading (sample #1, only). 6. Rinse a clean 125 ml Erlenmeyer flask with deionized water. Deliver approximately 20 ml of unknown acid into the Erlenmeyer flask. The tip of the buret should be approximately 1/2 inch below the top of the flask to avoid loss due to splashing. 7. Add 2 or 3 drop of phenolphthalein indicator. (Above your lab bench). 8. Titrate the unknown acid by adding standard NaOH (from the buret). Swirl the flask to mix the solutions during the addition of base. As the base is added you will observe a pink color localized at the spot the NaOH enters the solution (this is due to a localized high base concentration). Occasionally, rinse down the walls of your flask with deionized water (This rinses down any acid that has splashed onto the walls of your flask). Near the end-point, the pink color "flashes" throughout the solution and remains for a slightly longer time (1-2 seconds). When this occurs, add the NaOH drop by drop and eventually half-drops until the pink color remains (for at least 30 seconds). This is the end-point! NOTE: If you over-shoot the end-point (too much NaOH is added), add 1-2 more ml of the Unknown acid and then add NaOH again until a proper end-point is reached. Be sure
The objective of this experiment is to study the continuous variations method that is used to determine the composition of the solution Ni2+ ethylenediamine complexes.
A complexometric titration takes place in an aqueous sample inorder to displace water from the ion. As the metal ion will be ionated once in solution therefore, empty valence empty shells are achieved [1]
of Copper Sulphate. To do this I plan to work out the amount of water
This experiment consists of titrating the ferrous ion with permanganate ion to study the oxidation-reduction reaction. The ions react in acidic solution to give ferric ion and a reduced ionic form of manganese. All the reactants and products except permanganate ion are weakly colored, whereas permanganate is a very intensely colored ion. Then a solution of permanganate is removed as long as there is a ferrous ion present to react with it. But as soon as the entire ferrous ion has been oxidized, the next small portion of added permanganate colors the solution. The first appearance of a permanent pink color indicates the endpoint of the experiment. From the titration it will be able to calculate the percentage of iron in the sample from the data.
For this experiment we used titration to standardize the exact concentration of NaOH. Titration is the process of carefully adding one solution from a buret to another substance in a flask until all of the substance in the flask has reacted. Standardizing is the process of determining a solutions concentration. When a solution has been standardized it is referred to as a standard solution. To know when a solution is at its end point an indicator is added to acidic solution. An indicator is an organic dye that is added to an acidic solution. The indicator is one color is in the acidic solution and another color in the basic solutions. An end point occurs when the organic dye changes colors to indicate that the reaction is over (Lab Guide pg. 141).