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University Degree: Chemistry
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- Marked by Teachers essays 7
Local rules apply * The sealing of melting point tubes by Bunsen must be done away from flammable solvents * After practical all waste solvents much be disposed in appropriate receptacles * Do not look directly at UV light Method Each group is given 2 unknown compounds to identify Thin Layer Chromatography 1. Prepare solution with 10ml ethanol in 90ml hexane and place in a sealed chromatography tank at least 20 minutes before analysis 2. Prepare two fine needles using Bunsen burner.
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Unsaturated carbons are also called alkenes or olefins with a general formula of Cn-H2n. In contrast to alkane, the bond consists of one sigma and one pi bond. Hydrocarbon can also be classified into groups based on their structure that are aliphatic and aromatic. Aliphatic compounds are divided into three classes; those with single bonds are called alkanes and are said to be saturated and those with double or triple bonds are alkenes and alkynes and are unsaturated compounds. Aromatic compounds on the other hand are compounds containing close rings of carbon atoms in which the pi-electron are delocalised across the structure.
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Introduction to Molecular Modeling & Independent Molecular Modeling Project. Certain properties and characteristics of different molecules were observed via molecular modeling using the computer software PC Spartan Pro. Specifically, two molecules were se4 star(s)
As the program manual says, azomethine ylides are proposed intermediates of 1,3-dipolar cycloadditions. The ? system bears a formal negative charge which is neutralized by a formal positive charge in the ? system. Azomethine ylide was further studied by looking into the compound's electron density. Figure 2: Electron Density of Azomethine Ylide Figure 2 shows the distribution of electrons in azomethine ylide. By convention, red areas represent electron-rich regions while blue areas are those for electron-poor egions. The figure shows that nitrogen, being a highly electronegative compound, causes electrons to spend most of the time near the said atom.
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An additional factor is the "common ion" effect, this further reduces the solubility of the precipitate. When Ag+ is precipitated out by addition of Cl- Ag+ + Cl- =<-> AgCl(s) the (low) solubility of AgCl is reduced still further by the excess of Cl- which is added, pushing the equilibrium to the right. Next, the weighed form of the product should be of known composition.The product should be "pure" and easily filtered. It is usually difficult to obtain a product which is "pure", i.e. one which is free from impurities but careful precipitation and sufficient washing helps reduce the level of impurity.
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react with Fehling's reagent. In the reaction, aldehyedes is oxidized to form a carboxylate and copper (11) ion is reduced to copper (1) oxide which appear as brick-red precipitate. Both aliphatic and aromatic aldehyde (not ketone) react with Tollen's reagent. In the reaction, aldehyde is oxidized to form carboxylate and the Ag(NH3)2 positive ion which appear as silver mirror on the wall of the test tube. An aldehyde will react positively with schiff's reagent giving pinkish purple colour solution. However it is not a good confirmatory test as benzaldehyde gives negative result and propanone gives positive result.
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Nuclear power generation was once thought to be the power source of the future. However, accidents at nuclear power facilities and disposal problems with the products of energy generation using this method have resulted in the rethinking of this energy source. Electric vehicles have been touted as the next step to eliminate reliance on fossil fuels. The stumbling block on this path is efficient and lightweight storage of enough power to parallel fossil fuel vehicles already in use. To date, there has been no storage system that can produce enough power to economically and safely power a vehicle for realistic use.
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