Lab Report- Grand Central Equation Introduction In this experiment, we created Zinc Iodide yet again. However, this time we did it through different means which caused a different kind of reaction. Better said, in this lab we learned that reactions can take multiple steps to go into completion. We also analyzed which was the more efficient way to generate Zinc Iodide. Focus Question Should chemists prepare Zinc Iodide, from its elements or from a Double Replacement Reaction between Barium Iodide and Zinc Sulfate?
| Centrifuge: used to isolate the solid from the solution | . Focus Questions: When acidified water is not used in the zinc and iodine synthesis, zinc hydroxide is formed. How can it be identified based on the amphoteric nature. When zinc and iodine react without the presence of acetic acid in the water, zinc hydroxide forms. This is evident because the substance tested positive for both the acid test and the base test for zinc hydroxide.
Purpose: The following lab was conducted in order to determine the iron (〖Fe〗^(2+)) content in an unknown sample by way of reduction-oxidation titration using a standardized potassium permanganate solution. Theory: Titration is one of the most commonly used methods for determining the amount or concentration of an unknown substance. Chemical analysis can be performed on redox titrations, if the following conditions are met: “The reaction is thermodynamically spontaneous enough to be stoichiometric”, “The reaction is kinetically fast enough to give operationally ‘instant’ results”, “No side reactions occur”, and “a satisfactory indicator exists”. These conditions are what makes potassium permanganate (〖KMnO〗_4) a very useful analytical oxidation agent as it easily fits the criteria. The half reactions for this system are: Oxidation of 〖Fe〗^(2+): 〖Fe〗^(2+)→ 〖Fe〗^(3+)+1e^- Reduction of 〖MnO〗_4^-: 〖MnO〗_4^-+8H_3 O^++5e^-→ 〖Mn〗^(2+)+12H_2 O Which produces the following overall equation: 〖MnO〗_4^-+8H_3 O^++5〖Fe〗^(2+)→5〖Fe〗^(3+)+〖Mn〗^(2+)+12H_2 O Equilibrium is initially obtained at a very slow rate, therefore the titration is carried out in the presence of excess sulphuric acid (H_2 〖SO〗_4) at a high temperature; in order to drastically increase the rate at which equilibrium is attained.
I believe we did our procedures accurately. The precipitate was Zinc hydroxide which is amphoteric in nature. Meaning it can react both with acid and base to form salt. We got a white precipitate of zinc hydroxide and it reacted to make salt with both the base sodium hydroxide and the acetic acid. Our result would have been clearer to observe if we centrifuged it long enough because we might have lost some of the precipitate while washing it since it was not centrifuged long enough.
When observing the solubility I asked Salowa to take a second glance at the iodine or zinc in the test tube, just incase I missed something. Likewise when Salowa was reading the graduated cylinder, I double-checked it to make sure we both agreed on the number. In a few cases we did not both agree on what the reading of the graduated cylinder was. In this case we called over a third person, Ardit, to read the graduated cylinder and see who he agreed with. This gave us accurate results by not having errors in our data.
Conformation ___2___ is the more stable (1 mark) In a similar fashion, draw the two conformations for trans-1-bromo-3-methylcyclohexane. (2 marks) 2 Chemistry 250 Stereochemistry Workshop Febraury 2013 Question 3 (10 min) Build the model for 1,2-dimethoxyethane (CH3OCH2CH2OCH3). There are two staggered and two eclipsed conformation around the bond formed between C-1 and C-2. All four of these conformations have different stabilities. (HINT: Learn to simplify when building the models.
Afsana Islam CHEM 106 – LAB Lab Report #4 03/02/2015 Focus Questions: Is mass conserved in the chemical reaction that you studied in lab? The mass of the zinc and iodine were definitely conserved. The mass did not change much after the chemical reaction occurred. Raw Data: Experiment # Mass of “R” boiling tube Mass of Zinc used in Mass of Iodine used in Mass of excess zinc and “R” boiling tube after r/h/c Mass of excess zinc and “R” boiling tube after r/h/c a 2nd time Mass of “P” boiling tube and boiling chip Mass of “P” boiling tube, boiling chip, and zinc iodide after h/c Mass of “P” boiling tube, boiling chip, and zinc iodide after h/c a 2nd time 1 40.63g 2.00g 3.00g 40.83g 40.83g 41.46g 45.29g 45.29g 2 40.63g 1.00g 2.00g 41.09g 41.09g 42.25g 44.60g 44.60g
lder report Lab 5: Diels-Alder Reaction The laboratory procedure used was written by Dr. John Barbaro of Rocky Mountain College. The Diels-Alder reaction is a well known example of cycloaddition chemistry. It is commonly known as [4+2] Cycloaddition. The reactants in the Diels-Alder reaction are a 1,3-diene and an alkene called the dienophile. The dienophile usually contains an electron-withdrawing group that is in conjugation to the double bond, making the double bond “electron poor”, thus initiating the addition reaction.
(White Light/Black Rain: The Destruction of Hiroshima and Nagasaki) The United States along with the United Kingdom would embark on a race to build the first atomic bomb. This great race was named the Manhattan Project. In anticipation of beginning the program, there was an extensive amount of fieldwork covered in nuclear energy between 1932 and 1939. The discovery of the neutron by James Chadwick in 1932 clarified the reason for atomic weights of the same element differed. (Delgado 43) Research in atomic energy progressed when scientists learned that using a neutron to bombard atoms performed better than protons and alpha particles.
His predictions proved to be quite accurate when these new elements were discovered and characterized. Today, we are sending you back to 1869 to see if you can recreate a periodic table as Mendeleev originally did by grouping together elements with similar properties and looking for trends within each group. If you are successful, you will be able to identify the unknown elements. Part A: Examining properties and trends. You will separate the elements into piles based on different properties.