Atmospheric pollutants in the lower atmosphere essay.
Atmospheric pollutants in the lower atmosphere The atmosphere becomes polluted by both natural processes and the activities of humans. Volcanoes can release toxic gases including sulfur dioxide. Lightning produces toxic nitrogen oxides and ozone. Let us examine some gases that pollute the lower atmosphere. Lower atmospheric pollutants often include particulates such as soot from forest fires and the exhaust from industry. Metal dusts and concrete dusts also are atmospheric pollutants, as are vapours from solvents used in industry and domestically. Carbon dioxide The concentration of carbon dioxide has shown a gradual increase during the twentieth century. The burning of fossil fuels such as coal and oil products has caused this gradual increase in carbon dioxide levels. This increase in carbon dioxide is one of the factors that scientists believe has added to global warming. This is sometimes referred to as the 'enhanced greenhouse effect'. Carbon dioxide absorbs infrared (IR) radiation that is re-radiated by the Earth's surface. This process is vital in ensuring that the Earth does not lose too much heat and become a cold, lifeless planet. Too much carbon dioxide, however, leads to higher heat retention with consequent changes to the abiotic and biotic environment. Carbon monoxide Carbon monoxide is a lower-atmospheric pollutant. Road traffic emissions account for up
An Investigation Into What Affects How Much Copper Is Deposited On A Pure Copper Cathode.
An Investigation Into What Affects How Much Copper Is Deposited On A Pure Copper Cathode. Plan Aim The aim of this investigation is to find out what effects the amount of copper deposited on a pure copper cathode. We already know that by passing an electric current through a copper sulphate solution the atoms at the anode dissolve while at the cathode positive ions are gathering and collect up. Variables Variables are what we can change in the experiment here are some of them: * We can change the amount of current passed through the electrodes. * We can change the strength of the solution by adding and reducing the amount. * We can also vary how long the experiment is left while an electric current is passed through the electrodes. We choose to change the amount of current passed through the electrodes using a variable resistor. I choose this because it is simple and gives off good and clear results. Predictions A simple prediction would be to say that the mass of copper deposited at the anode would decrease, and the mass of copper deposited at the cathode would increase. It is also possible to predict when using time as a variable, that the relationship between the time the current flows and the mass of copper deposited at the cathode will be proportional. I can then predict that if I double the time of the experiment, I will be doubling
Is Aluminium a Suitable Metal for Manufacturing Bicycles?
Is Aluminium a Suitable Metal for Manufacturing Bicyces? Extraction Process for Aluminium The ore of aluminium is Bauxite and it contains 52.9% aluminium and 47.1% oxygen. The extraction of aluminium takes three main stages: * The mining of bauxite * Refining of the ore to produce aluminium oxide * Electrolysis of aluminium oxide to produce aluminium Mining Bauxite is mined by removing the top layers of soil and then removing the ore from the area by use of explosives to break it into moveable pieces. The bauxite is then crushed on site, sometimes washed to remove soil and clay and then dried in a kiln or it may just be dried. It is then ready to be transported by railway or ships to refineries. Refining Bauxite is made of aluminium oxide-2-water (Al2O3.2H2O) and silicon (IV) oxide (SiO2) and iron (III) oxide (Fe2O3). The bauxite is refined to extract pure aluminium oxide: * The bauxite is ground * Then heated with concentrated NaOH (aq) * This forms a solution of sodium aluminate and sodium silicate, plus a residue of iron (III) oxide, which is removed. * CO2(g) is blown in and the sodium silicate remains in solution, but a precipitate if aluminium hydroxide is formed. * The mixture is then filtered, washed and heated to leave anhydrous aluminium oxide (alumina). * Al2O3 is left. Electrolysis This is how the aluminium and oxygen is separated, through
the chemistry of iron
Write an essay on the chemistry of iron Introduction Iron has an electronic configuration of . It is a d-block element. Also, iron is a transition metal. It has all the properties of a transition metal, including variable oxidation states, complex formation, coloured ions and catalytic properties. General properties of iron Like other metals, iron has a shiny surface. It conducts heat and electricity well. Iron is very tough, so it is always used as building materials. Moreover, iron is cheap when compared with other metals; therefore, it is widely used in all kinds of manufacturing. Variable oxidation states Since the successive ionization enthalpies of transition metals only increases gradually and in particular, the energy difference between 3d and 4s shells is very small, transition metals have variable oxidation states. Iron has two major oxidation states: +2 and +3. Fe2+: Fe3+: As Fe3+ has a half-filled 3d subshell, Fe3+ has extra stability over Fe2+. This can be reflected from the particularly low third ionization enthalpy. Fe2+ can readily be oxidized to Fe3+. Coloured ions and complex formation Complex is formed when ligands form dative covalent bonds with the central atom/ion. Transition metal ions like Fe2+ and Fe3+ can form complexes with ligands readily because they have large charge/radius ratio and low lying vacant d-orbitals available for
Effect of increasing charge on Mass of Copper Deposited.
Chemistry Coursework Effect of increasing charge on Mass of Copper Deposited Diagram Method * I will fist weigh the cathode * I will then set up the apparatus as shown in the diagram * Then switch the power pack on * I will wait 10 minutes and then weigh the cathode, I will do this for 50 minutes every 10 minutes My Independent Variable is the Charge My Dependent Variable is the Mass of the cathode The controlled variables are the concentration of Copper sulphate and the temperature Prediction: I can predict that there will be a positive coloration between the increase of charge and the amount of copper produced at the cathode. Scientific Explanation: Current is the flow of electrons in a circuit - in the case of electrolysis the flow is towards the cathode and away from the anode. Within the solution, the current flows because of the presence of negative and positive ions. Copper sulphate is an ionic salt, which contains no free electrons. However, it does contain ions (which are charged particles) fixed in a crystalline structure. When copper sulphate is dissolved, the copper sulphate solution becomes an electrolyte because the ions become free to move and they can conduct electricity. At the cathode, the copper ions, being more reactive than the hydrogen ions are deposited whilst the hydrogen ions
An investigation into the factors which affect the currentflowing during electrolysis
An investigation into the factors which affect the current flowing during electrolysis Introduction Electric current is the flow of electrons. Sodium chloride in solution is able to conduct electricity because when dissolved sodium ions and chloride ions are produced. The chloride ions that are negatively charged due to their extra electron are attracted to the anode where they give up that extra electron and bond with other molecules to form the chlorine gas, Cl2. The extra electron then flows through the circuit to the cathode. H+ ions in the solution are attracted to the negative charge of the cathode and there they gain the extra electrons that originally belonged to the Cl- ions. Hydrogen gas is then formed and the circuit is complete. 2e + 2H+ --> H2 2Cl- - 2e --> Cl2 Variables Concentration of NaCl- The bigger the concentration the more ions will be in the solution. This will mean that more ions will get to the electrodes, which means more electrons will get into the wire. This will greater the current. Temperature- the ions will go quicker to the electrodes as the water will vibrate quicker when hotter. This will increase the current. Voltage- The current would be decreased because by ohm's law v=ir Surface area of the electrodes- if the surface area on the electrode increases there will be more space for the ions to go to and therefore the current will
Biodegradable Polymers
Biodegradable polymers are environmentally friendly. Write an article for your school magazine to promote more extensive use of biodegradable polymers in Hong Kong. As many of you would know, Hong Kong is heavily polluted and solid waste pollution remains a serious problem to be solved. In Hong Kong, an average of 23000 tonnes solid waste were produced per day, and this figure is obviously increasing. Among all the solid wastes that we dispose of daily, non-biodegradable plastics are one of the kinds that are the most difficult to handle and pose serious threats to our environment. But do you ever think of any solutions to this problem? In fact, everyone can play a part in protecting our Earth from plastics by using biodegradable polymers as substituents. Problem caused by non-biodegradable polymers We have been using non-biodegradable plastics for so many years that we simply ignore their harmful effects. Plastics produce various problems in different areas, including ecological, environment and economical fields. A. Ecological problems Plasticizers and polychlorinated hydrocarbons used in the manufacture of plastics pose a health hazard and they may incorporate into the food chain, eventually getting into human body. Plastic wastes in the sea directly affect fishes. Small fishes have been found dead with their digestive tracts clogged by fragments of plastic foam
