Importance of Chemical Bonding | Essay

Importance of Chemical allianceing EssayGeorge chocolate-brownChemical confederations are either ionic or covalent. When a admixture is present the bond is ionic as an negatron is given from the go up to the non-metal, so the two ions are attracted to on the whole(prenominal) other. When a bond is between two non-metals then it is covalent meaning that in the outer(a) electron shells of the two pinpoints bonded electrons share electron to complete their outer electron shell.When two atoms bonded unneurotic are non the same, the electrons pass on not be shared equally as each atom will be positively or negatively charged in relation to each other. This value is peakd as the balance of the negativeness of each atom present. The electronegativity of an atom is the potential for the atom to attract shared electrons towards itself. The difference in electronegativity between ionic bonds is greater than that of polar covalent bonds and greater still of non-polar covalent bond. An poser of a non-polar covalent bond is H-I as the difference in electronegativity isnt very high. An precedent of a polar covalent bond is H-Cl as the difference in electronegativity is higher than 0.5 and lower than 1.7 and an moral of an ionic bond would be Na-Cl as the difference in electronegativity is above 1.7.In aim 1 it eject be observed how the electrons are shared in ionic and covalent bonds. This explains the high difference in the resultant electronegativity between ionic and covalent bonds. Metal, as an ion, donates an electron making it positively charged and a non-metal, as an ion, gains an electron making it more negatively charged meaning the attraction between ionic bonds is greater than that of covalent bonds. noodle bonded essences are more polar than covalent bonded substances thus a better issue. NaCl has a much high boiling point (around 1413c) than for example HCl (around -85c)Sodium Chloride, better k todayn as table salt, is an example of an Ionic bonded substance overdue to the high difference in electronegativity. Sodium and centiliter as elements are very reactive and thus poisonous to the merciful body in large quantities if uncontrolled. So the fact that sodium and chloride are ionically bonded abets to control the concentration of sodium and chlorine in the body as it can single be broken down when it needs to be in the liver. Sodium and chlorine is needed In low concentrations for mainstay cell bleeds in spirit cells for maintaining the resting potential of nerve axon cells which is -70 mV (Hall et al., two hundred9) maintained by the sodium potassium pump. It is required for the nerve cells in the human body to function. Its the reason for why you can feel or can react to stimuli.A blood cell is forever and a day non polar, where the bonds between atoms in the molecule are non-polar an example of this would be H-I. pee is an example of a polar covalent bond as it consists of polar covalent bonds H- O and the molecule is asymmetrical. This means that pissing system is a good solvent allowing it to transport sugars and salts around the body, in blood, as they can be easy dissolved in an aqueous solvent such as water. In solve 2 you can construe the relative charge of the molecule in water. CCl4 is example of a molecule of which its atoms are polar bonded together but due to the symmetry of the molecule observed in figure 2 the polarity of the molecules cancels itself out, and it acts as if its non-polar in intermolecular interactionsThe chroma between intermolecular bonds is a lot weaker than the strength of intramolecular bonds and the weakest nisus of intermolecular bond is a bond that uses van der Waals forces or an fast induced-dipole bond. These are observed when a come outby non-polar molecules experiencing an instant(prenominal) dipole, due to the ergodic nature of electron misdirects oscillating on molecules, which induces a dipole of some other molecule, it may cause a ripple effect inducing dipoles on nearby non-polar molecules. Larger molecules have a larger electron cloud which means the induced and potential electronegativity of instantaneous dipoles would be stronger. wagon train der Waals forces is the attraction that occurs between all molecules polar or non-polar, but is the only source of intermolecular attraction between non-polar molecules. Lower boiling points will be observed of substances of similar elements that are polar, dipole-dipole bonds or eventide stronger heat content(dipole-dipole) bonds, than that of non-polar Van der Waals force bonds, as they are much stronger so it requires more energy(heat) to interrupt them. Figure 3 is an example of an induced dipole bond from an instantaneous dipole.Hydrogen bonding (an example of a strong dipole-dipole bond) is another example of an intermolecular. Standard hydrogen bonding is an intermolecular bond where a hydrogen from one molecule is attached to one of the most electronegative elements oxygen, northward or fluorine of another molecule. Figure 4 shows a plot of a hydrogen bond between two water molecules. These bonds help to keep the water molecules together so it requires more energy for the substance to change state from liquid into a gas. It to a fault means when water is a solid ( looking glass) it is less dense than when it is a liquid, which is unusual as usually substances tend to expand when they heat up. Heat is a measure of energizing energy of a substance, so when substances, molecules or atoms, has more kinetic energy it is more fluid, less packed together (less dense). You can see in figure 4 that each oxygen atom is bonded from a combination of hydrogen (intermolecular) and covalent (intramolecular) bonds to 4 oxygen atoms. in that respect is a lot of free space around these atoms when they are structurally bonded this way, so this is why ice is less dense than water. The structural function of ice is important for all seaso nal marine life and some shoot organisms as it allows ice to float.An example of a more complex intermolecular bond is ionic hydrogen bonding. Potential uses is discussed in the word BIOPHYISCAL (Kaledhonkar et al., 2013). The term states Standard hydrogen bonds are of great importance for protein structure and function but Ionic hydrogen bonds often are significantly stronger than standard hydrogen bonds and exhibit unique properties which allows them to be used in protein plica (polypeptides), modification in the golgi apparatus, enzyme active transport centres and the formation of membranes, processes that are all critical for life. Ionic hydrogen bonding is explained further in an article in chem. rev. (Meot-Ner (Mautner), 2005). The article states that ionic hydrogen bonds (IHBs) that form between ions and molecules with bonds strengths of 5-35 kcal/mol, up to a third of the strength of covalent bonds. Ionic hydrogen bonds are believed to be the strongest intermolecular bon d but still only up to a third the strength of a covalent bond. So even the strongest intermolecular bonds are weaker than intramolecular bonds.Word Count 1058Referencesbbc.co.uk, (2014).BBC Higher Bitesize Chemistry Bonding, structures and properties Revision, Page2. online procurable at http//www.bbc.co.uk/bitesize/higher/chemistry/energy/bsp/revision/2/ Accessed 2 Dec. 2014.Chemprofessor.com, (2014).Intermolecular Attractions or van der Waals Forces. online Available at http//www.chemprofessor.com/imf.htm Accessed 2 Dec. 2014.Hall, A., Hickman, G., Howarth, S., Middlewick, S., Owens, N., Reiss, M., Scott, A. and Wilberforce, N. (2009).Salter-Nuffield Advanced biological science A2 Student Book. capital of the United Kingdom Edexcel Pearson, p.201.Kaledhonkar, S., Hara, M., Stalcup, T., Xie, A. and Hoff, W. (2013). Strong Ionic Hydrogen Bonding Causes a Spectral Isotope Effect in Photoactive Yellow Protein.Biophysical Journal, 105(11), pp.2577-2585.Meot-Ner (Mautner), M. (200 5). The Ionic Hydrogen Bond.Chem. Rev., 105(1), pp.213-284.Physicsofmatter.com, (1998).Hydrogen Bond Disorder in water ice Structures. online Available at http//www.physicsofmatter.com/NotTheBook/Talks/Ice/Ice.html Accessed 2 Dec. 2014.Page 1 of 7Soil Water contamination wheal Jane consequentSoil Water Contamination Wheal Jane IncidentThe Wheal Jane incident was a significant exploit water emanation event. The incident occurred in 1992, shortly after the mine closure. This report provides a brief description of the mine, the incident itself and the resulting aftermath.Wheal Jane exploit is located near the village of Chacewater, in Cornwall. The mine itself was formed in 1861, after the merging of five smaller mines. The oldest mine workings from the area were thought to ascertain back as far as the 1740s (Cornwall Calling, 2017). The mine had worked many mineral lodes over its life metre, producing tin, copper, and silver-lead (Cornwall in Focus, 2017). In the years leadi ng up to its closure, the mine was primarily extracting cassiterite, the main source ore of tin, but older workings also produced pyrite and arsenopyrite, with the modern development drives taking the mine to 450 meters below surface level (University of Exeter, 2002).The mines of the Gwennap parish were all interconnected, with Wheal Jane connected to the neighbouring, working mine pile Wellington, and to the abandoned workings of United mines. Wheal Jane was an extremely wet mine, requiring dewatering measures in the region of 60,000 m day-1 in the winter months. The wield water was highly acidic, owing to the dissolved metals from the sulphide mineral deposits. Approximately half of pumped water was tough before existence finishd into the Carnon river (Bowen, Dussek, Hamilton, 1998). Wheal Jane Mine had been working, on and off, from this time until its eventual closure in 1991 due to financial difficulties, primarily relating to the low price of tin, following the Interna tional Tin concord in 1985. Much of the mines infrastructure and equipment was sold off at the time of its closure, with the mines operational dewatering systems being turned off after a brass activity grant subsidising the pumping costs was withdrawn (University of Exeter, 2002).After the mine closure, and the cessation of the government grant, the operational dewatering pumps were switched off, leaving only the tailings dam pumps remaining. With the dewatering measures stopped, the water level flush and learned the expansive voids underground, with the sulphide mineral bearing rock now being leached by the rising ground water. The NRA (National Rivers Authority, now part of the surroundings Agency) was concerned of the potential of Acid Mine Drainage (AMD) into the Carnon river and commissioned a survey to determine the potential impact of a mine water discharge, and its likely discharge points and timing. The investigation proved difficult to predict due to the un cognise v olume of connected, un-surveyed mine workings which would also need to fill before release (Bowen, Dussek, Hamilton, 1998). The NRA continued to monitor the water levels and water theatrical role without the year.On November 17th 1991 the mine water levels reached 14.5 m AOD, and a mine water discharge event occurred through Janes adit. The water treatment lagoon onsite was quick overwhelmed by a flow of approximately 5,000 m per day of AMD at a pH of 2.8 (Bowen, Dussek, Hamilton, 1998). The NRA had contingency plans in status and immediately reacted by adding lime at the head of the adit to upraise the pH and precipitate the metals from the mine water. A plug was constructed near the admittance of Janes adit and the water pumped out into the tailings dam (University of Exeter, 2002).On January quaternary 1992 a technical issue meant that the pumps to the tailings dam were stopped. The mine water levels quickly rose by an estimated 4 meters. The mine water built up and, on January 13th 1992, discharged through the Nangiles adit, which was the second lowest known discharge location after Janes adit. This released an estimated 50,000 m of AMD (pH of 3.1) into the Carnon river over a close of 24 hours, flowing through the Restonguet Creek, Carrick Roads and into the Fal estuary (Bowen, Dussek, Hamilton, 1998).The contaminated water created a highly visual pollution event, as oxidation caused the iron rich water to turn a yellow-brown ochre colour, drawing general media attention and causing much alarm to the community ( CLAIRE, 2004).The mine water also contained considerable concentrations of heavy metals, most significantly being the presence of over 600 parts per billion Cadmium (University of Exeter, 2002).Following the discharge, naked as a jaybird pumps were installed by the owners to pump water from the adit directly into the tailings dam as a short-term issue.Monitoring after the incident proved that the make of the mine water discharge pr oved to be short-term only, with the NRA stating that There appears to have been no major adverse effects from the incident on the biota of the estuary. (National Rivers Authority, 1995). However, it was clear after the event that the mine water could not be left unchecked, and thus a water treatment solution was proposed.The NRA proposed both an active and passive treatment system. In 1994 a pilot passive treatment plant (PPTP) was constructed, as a research manner for potential long-term treatment options. An active treatment plant was constructed in 2000.The PPTP contains three different treatment flows, all containing aerobic reed beds for removal of Iron and Arsenic, an anaerobic cell for removal of zinc, copper, cadmium and iron by bacterial reduction, and an aerobic rock filter which removes manganese through issue of algae (University of Exeter, 2002). The three streams differ however in the pre-treatment. One stream is first treated with lime to raise the pH, the secon d is first passed through an anoxic limestone drain, and the third stream involves no pre-treatment at all ( CLAIRE, 2004). A report into the performance of the PPTP found that it offered inconsistent performance, and water discharge commonly exceeded the permitted water quality guidelines. The PPTP was also only processing 0.6 l/s of contaminated water, The active treatment plant took over from the PPTP in 2000. The process involves the addition of lime to increase the pH, and flocculant to precipitate out the metals in solution. The metal precipitates form a sludge, which is sent to a hold tank, and onto the tailings dam. The treated mine water is discharged out into the Carnon river. This system treats an average of 200 l/s, at a metal removal efficiency of 99.2% ( CLAIRE, 2004).Whilst there have not been any significant long-term environmental impacts from the incident, it serves as a stark reminder of the potential environmental mishap that can come from mining activities, par ticularly from historical mines which were not dependant to the same environmental regulations that are in place today.ReferencesCLAIRE. (2004). Mine Water Treatment at Wheal Jane Tin Mine, Cornwall. CLAIRE (Contaminated dry land Applications in Real Environments), 1-4.BBC. (2014, June 3). Pumping the polluted water from mines. Retrieved from BBC News http//www.bbc.co.uk/news/uk-england-26573994Bowen, G. G., Dussek, C., Hamilton, R. (1998). taint resulting from the abandonment and subsequent flooding of Wheal Jane Mine in Cornwall, UK. London Geological Society.Cornwall Calling. (2017). Retrieved from Cornwall Calling http//www.cornwall-calling.co.uk/mines/carnon-valley/wheal-jane.htmCornwall in Focus. (2017). Cornwall in Focus. Retrieved from http//www.cornwallinfocus.co.uk/mining/whealjane.phpNational Rivers Authority. (1995). Wheal Jane Mine Water Study. Ashford Knight Pisold. Retrieved from Environment Data http//www.environmentdata.org/ trilby/repository/ealit2627/OBJ/20000 033.pdfUniversity of Exeter. (2002). The Wheal Jane Incident and water quality. Retrieved from Projects University of Exeter https//projects.exeter.ac.uk/geomincentre/estuary/Main/jane.htm