Properties of Hydrocarbon

Title: Properties of Hydrocarbons Introduction: Hydrocarbons are organic compounds that contain only hydrogen and carbon. The simplest form of hydrocarbon is the methane, which have the structure of CH4. The hydrocarbons can be divided into two groups that are saturated and unsaturated hydrocarbon. The saturated hydrocarbons are the compounds in which all the bonds of the carbon contain single bond and all the carbons are filled with 4 bonds that are attached to other atoms. The single bond consists of a sigma bond. The saturated hydrocarbon is also known as alkane, which belongs to a homologous series of organic compounds in which the members differ by a constant relative molecular mass of 14. The chemical formula is Cn-H (2n+2), where n is the total number of carbons. The compound is said to be saturated when they follow Cn-H (2n+2), which is to say there are no double bonds. Unsaturated hydrocarbon, unlike saturated hydrocarbons, contain one or more carbon-carbon multiple bonds such as double bonds, triple bonds, or both. Instead of C – C, it contains C = C or C = C. These compounds rose due to the loss of two hydrogens because the carbons can only have four total bonds to it. 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

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Variability and relative stability of oxidation states

Matt Carruthers Variability and relative stability of oxidation states In this essay the concentration will be on the oxidation states of the transition metals rather than the entire periodic table. An oxidation state is a number assigned to an element in a compound according to some rules. This number enables us to describe oxidation-reduction reactions, and balancing redox chemical reactions. Compared to Group II elements such as calcium, transition elements form ions with a wide variety of oxidation states. Calcium ions typically don't lose more than two electrons, whereas transition metals can lose up to nine. The energies required to remove electrons from calcium are low until you try to remove electrons from below its outer two s orbitals. In fact Ca3+ has an ionisation enthalpy so high that it rarely occurs naturally. However a transition element like vanadium has roughly linear increasing ionisation enthalpies throughout its s and d orbitals, due to the close energy difference between the 3d and 4s orbitals. Transition metal ions are therefore commonly found in very high states. Certain patterns can be seen to emerge across the period of transition elements: The number of oxidation states of each ion increases up to Mn, after which they start to drop. This drop is due to the stronger pull from the protons in the nucleus towards the electrons, making them

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Determination Of Nickel By Gravimetric Analysis

Title : Determination of Nickel by Gravimetric Analysis Objective : * To determine the amount of nickel in a given salt. * To calculate the weight percent of nickel in the salt and to compare with the Theoretical value * To study the gravimetric analysis method to determine the compound in a certain unknown salt Introduction and background Gravimetric analysis is a technique through which the amount of an analyte (the ion being analyzed) can be determined through the measurement of mass. Gravimetric analysis depend on comparing the masses of two compounds containing the analyte. The basic method of gravimetric analysis is fairly straightforward. A weighed sample is dissolved after which an excess of a precipitating agent is added. The precipitate which forms is filtered, dried or ignited and weighed. From the mass and known composition of the precipitate, the amount of the original ion can be determined. For successful determinations a few criteria must be met. First, the desired substance must be completely precipitated. In most determinations the precipitate is of such low solubility that losses from dissolution are negligible. 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

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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 se

Introduction to Molecular Modeling & Independent Molecular Modeling Project Discussion: Certain properties and characteristics of different molecules were observed via molecular modeling using the computer software PC Spartan Pro. Specifically, two molecules were selected as models: azomethine ylide and indole. In the azomethine ylide model, the electron density was observed while in the indole model, delocalization of bonds was taken into consideration. For the second model, azomethine ylide, single-point energy with Hartee-Fock 3-21G calculations using AM1 semi-empirical equilibrium geometry was also employed. Calculations were again based on the lowest-energy conformer of azomethine ylide, by the AM1 semi-empirical module. Figure 2 below presents the computer-generated model of azomethine ylide. Figure 1: PC Spartan Pro-Generated Structure of an Azomethine Ylide Figure 1 shows a general molecular structure of an azomethine ylide, a neutral molecule with a positive and a negative charge on adjacent atoms. 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

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Citing a number of contemporary issues, evaluate pressures on water and discuss the means by which the resource might be better managed in the future.

Citing a number of contemporary issues, evaluate pressures on WATER and discuss the means by which the resource might be better managed in the future. Water, after air perhaps, is the most precious resource available for use. Humans cannot survive much more than 5 days without drinking water, we need it to grow crops and feed animals, for cleaning and cooking, and for processing all man made goods and the provision of services. Although water is abundant on earth 96.5% of the water is saline (Pennington & Cech, 2010) which is undrinkable and unsuitable for agriculture and industry. A further 1.7% is stored as frozen water. So when discussing water as a resource, in this case, it is the 1.7% that exists as groundwater, in rivers, lakes, wetlands and soils that is being referred to, although not all of this is accessible. Currently the population of the world is over 6.8 billion (U.S. Census Bureau, 2010) and population growth worldwide is about 1.17% per year (Google, 2008). Life expectancy is increasing and coupled with these population factors are advancements in human society which are increasing our demands on water resources. In 2005 it was estimated that 48.6% of the world's population lived in urban areas (Encyclopedia of Earth, 2009) with this number constantly on the rise. Urban water provision usually depends on inefficient infrastructure which is susceptible to

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Method's of Drug Characterisation

Experiment 6 - Methods of Drug Characterization Aims . To gain experience of the analytical methods used for drug characterization Objectives . To gain experience in melting point determination, thin layer chromatography and UV spectroscopy 2. Application of the methods to identify an unknown substance Introduction The 2 most basic analytical techniques for identification of organic compounds are melting point determination and thin layer chromatography. Identification of compounds relied upon melting point determination before the modern analytical techniques of nuclear magnetic resonance, infrared and UV spectroscopy. Although thin layer chromatography still plays an important role in organic analysis. A solution of the unknown is spotted onto the silica coated plate about 1cm from the bottom and dried; it is then placed vertically into a tank with a suitable solvent inside. The solvent moves up the plate by capillary action and resolves the sample into discrete spots. The plate is removed and dried and the spots are viewed under UV or by treating it chemically with developing agent. For each component of the sample an Rf value can be calculated: Rf = distance moved by solute/distance moved by solvent Safety * Local rules apply * The sealing of melting point tubes by Bunsen must be done away from flammable solvents * After practical all waste solvents

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"Environmental degradation is neither the inevitable price of, nor a desirable path for, economic development

"Environmental degradation is neither the inevitable price of, nor a desirable path for, economic development." (UNDP, et al, 2005) Introduction Environmental degradation is now apparent on a global scale. In addition to the deterioration of what were once considered free goods (such as air and water), escalating scarcity of natural resources, deforestation, desertification and threatened bio-diversity are now commonplace across the spectrum. There are certainly no reservations over the scale of this degradation, however there is much controversy concerning the apparent environmental degradation - economic development nexus. Many have argued that short-term tradeoffs exist in the form of environmental degradation, for superior long-term economic gains. One of the positions put forward is that environmental degradation is the result and inevitable price of economic development. This viewpoint is based on the Environmental Kuznets Curve, regarding environmental degradation as the 'necessary evil' for achieving 'economic development' and suggesting that environmental assets are degraded in the early stages of economic development, only to improve after some income threshold has been passed at a later point. In the last decade, extensive literature has argued that a direct link between environmental degradation and economic development is too simplistic and that the

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