This is evident because the substance tested positive for both the acid test and the base test for zinc hydroxide. Observations of the zinc and iodine reaction without acetic acid: After swirling, the solution starts off to be yellow, than changes to orange. During swirling becomes dark brown- reddish. The tube feels warm, which means that the reaction is exothermic. Soon, the dark red changes into black and then eventually lighter and lighter becomes colorless.
Also a very pale purple tint formed. Acid test: Added 2 mL of 1M NaOH- no Physical change was observed. Base test: Added 2 mL of .17M Acetic acid- No physical change observed. Table: Zinc (g) | Iodine (g) | Deionized water (mL) | Weight of boiling tube (g) | 1M NaOH(mL) | .17M Acetic acid (mL) | 2 | 2.01 | 5 | 40.73 | 2 | 2 | 2. Answer to focus question: Since it is amphoteric, it will act as an acid if reacts with base and act as a base when reacts with acid.
Ethan D. Wilhelm September 10, 2012 Chemistry 121 section 8 Friday 9-12 Sarah Gains Unknown Substance Lab Purpose: The purpose of this lab was to identify an unknown substance B by finding enough of its physical properties that we could eliminate all substances it can’t be. We use micro lab to help us find the boiling point, freezing point and mass. Then we tested the solubility of the unknown substance in water, hexane, and Alcohol. With this information we were able to find the identity of the unknown substance B. Procedure: Throughout this lab we were finding the physical properties of substance B.
2-propanol (bp=82 degrees C) 3. tetrahydofuran (bp=65 degrees C) 4. 1-butanol (bp=118 degrees C) 5. butanone (bp=80 degrees C) Give a better separation for the mixture to be distilled tetrahydofuran (bp=65 degrees C) because it is farthest from 100 degrees C Which alkyl halide would react fastest in a nucleophilic substitution using silver nitrate in ethanol (weak nucleophile, protic solvent)? 3-bromo-3-methylpentane (most
Emmanuel Omolola Orgo Chem 2 Sec #1 (4-6pm) October 8, 2012 Grignard Reaction with a Ketone: Triphenylmethanol Purpose: The purpose of this exeperiment was to synthesize tripheymethol from a Grignard reagent, phenylmagnesium, bromide, bromobenzene, and benzophenone. Since the Grignard reagent is such a strong nucleophile and base, it is important to prevent water and other protic materials from interfering with Grignard reagent are developed. The experiment involved two reactions. First the Grignard reagent, phenylmagnesiumbromide, was synthesised from bromobenzene, magnesium and diethyl ether. Once produced, the Grignard reagent was then used to synthesise triphenylmethanol by reacting it with benzophenone.
In this example I created the bicyclic ring system 4-cyclohexene-cis 1, 2-dicarboxylic anhydride from the starting materials of butadiene and maleic anhydride. What makes the Diels-Alder reaction so important is that it’s our first real look pericyclic reactions. It’s a useful method in the preparation of cyclic compounds which can be very stable in comparison to the acyclic starting materials I used. An important piece of information about the Diels-Alder reactions is that they are stereospecific, meaning that the dienophile and diene can only interact if they meet each other in the right geometrical angles and the molecules can fit into each other the right way. In this case we need the dienophile to be cis for this reaction to proceed because the two molecules need to approach each other at an angle parallel to each other.
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
The net reaction is: This reaction has been studied extensively and occurs for a wide variety of ketones. In general, the halogenations of a ketone can be represented as follow: The main evidence for any mechanism is provided by kinetic studies to determine an experimental rate law. Following the rate law of chemical kinetics, the differential rate equation for the reaction could be written as follow: Where k = rate constant; a, b,c are the orders of the reaction of S, I3-, and H+ respectively. I3- ion is the only coloured species in the reaction mixture, a spectrophotometer can is used to measure the change in its concentration, by applying the Beer-Lambert Law Where A= absorbance, ε= molar absorption coefficient, [I3-]= concentration and /= optical path length, that is, the distance travelled by the light through the solution. The ideal wavelength for the measurement of
2.7 – Micro-scale Cannizzaro Reaction with 4-Chlorobenzaldehyde Student ID: ###### Name: Students Name Date: November 8th, 2010 1 - Aim: To prepare and isolate the products of the Cannizzaro reaction of 4-Chlorobenzaldehyde. 2 - Introduction: In the presence of a strong base, an aldehyde with acidic α hydrogens tend to form enolates and undergo Aldol condensation but aldehydes with no α hydrogens such as benzaldehyde, instead undergo a self oxidation/reduction known as the Cannizzaro reaction. 3 – Reaction Scheme: [pic] 4 – Table of Reagents: |Compound |RMM |Wt/g |Mol | |4-Chlorobenzaldehyde |140.57 |0.302 |0.00214 | The limiting reagent was 4-Chlorobenzaldehyde The maximum possible yield was 1.07 mmol. 5 - Procedure: The experimental procedure was followed as detailed on page 75 and 76 of the laboratory manual. An accidental spillage occurred during the recrystallisation of the alcohol product, resulting in a significant loss of product.
Mendeleev realized that the physical and chemical properties of elements were related to their atomic mass in a 'periodic' way, and arranged them so that groups of elements with similar properties fell into vertical columns in his table. Gaps and predictions Sometimes this method of arranging elements meant there were gaps in his horizontal rows or 'periods'. But instead of seeing this as a problem, Mendeleev thought it simply meant that the elements which belonged in the gaps had not yet been discovered. He was also able to work out the atomic mass of the missing elements, and so predict their properties. And when they were discovered, Mendeleev turned out to be right.