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GCSE: Organic Chemistry
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Information taken from http://news.bbc.co.uk/2/hi/science/nature/6294133.stm Bioethanol is a biofuel and is produced from starch which later breaks down into glucose by the enzymes and forms yeast. When this is mixed with petrol it becomes a fuel which could be used in our cars and other purposes. It is a good idea because it is carbon neutral. It is carbon neutral in the sense it produces only a small amount of carbon dioxide during combustion and the plants makes use of all that carbon dioxide during the process of photosynthesis which therefore neutralizes the whole balance of excess carbon dioxide in the atmosphere.
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Another large factor is the internal combustion engine. As when any type of fossil fuel is burned, in factories, power stations and homes, they produce lots of different gaseous acids that are harmful to the environment, such as sulphur dioxide (SO2) and nitrogen oxide (NO+). The effect of releasing gaseous acids into the atmosphere, as a result of modern lifestyles, results in Acid Rain and more serious Global Warming. The gaseous acids released into the atmosphere are blown into the sky.
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Central London has had a dramatic cut in traffic since the introduction of the congestion charge. 40 000 less people are driving through the zone each day as the number of cars entering the zone has dropped by 38%. Since the introduction of congestion charges average speeds have risen considerably. For example: average speeds have risen from 3mph to 7.4 mph and 9.8 mph was the highest average speed on the Embankment. This however is not recent research which could mean that it is slightly unreliable. More recent research therefore, suggests that traffic levels have built up to be closer to pre-charging levels since February 2004.
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I will place the lithium into water and shut the stopper as quickly as possible to prevent gas from escaping. 5) I will then weigh the lithium and record my results From knowing that 1 mole of gas occupies 24,000cm� at room temperature and pressure I can deduce the amount of moles that I collected from the experiment Moles = 170 � 24,000 = 0.00708 With these figures I can deduce the number of moles from lithium that reacted by using the ratio of lithium to hydrogen in the reaction 2Li (s)
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Once the heated solution was taken out of the beaker, another 5ml of water was added so that the chicken didn't stick to the bottom of the filter paper during the filtration. 7. The heated solution was filtered and the solid residues removed. 8. The filtrate was then collected and transferred into a boiling tube, where it was divided into two samples of about two fingers, an extra one and the control. 9. 2-3 drops of copper sulphate (CuSO4)
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As the oxygen builds up in the top of the burette it will force the water down, thus allowing us to measure the amount of oxygen in the top of the burette. The burette holds a maximum of 50cm3 so the amount of gas collected cannot exceed this. There are two methods of measuring the rate of reaction. One is to measure the time it takes for the reaction to produce a certain volume of oxygen and the other is to measure the amount of oxygen produced in a certain length of time.
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I attached a condenser to the top of the flask and heated the contents gently until they boiled. I then refluxed the contents for 15 minutes. 3. I allowed the flask to cool and poured the solution slowly into a beaker leaving the anti-bumping granules in the flask. I added 10 drops of methyl orange indicator to the solution. The solution turned from colourless to orange. I then added 20cm3 of 2.0 moldm-3 hydrochloric acid to the solution. The solution turned pink and a precipitate formed immediately.
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Next I will put the polystyrene insulating lid on the tin can, with a thermometer sticking through the middle. Now I will be ready to commence the experiment. I will light the fuel and start the stopwatch. After 120 seconds, I will stop the burning and record the temperature of the water. I will also record the mass of the alcohol again. Below is a diagram showing the setup of my experiment: After having now done the experiment, I have obtained the following results. These are shown below in the table. Alcohol Initial Mass (g) Initial Temp �C ?
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New bonds form between carbon and oxygen in C02 and between hydrogen and oxygen in H20. Between successive alcohols, the structural difference between each alcohol is of course the CH2 group of atoms. So each alcohol has one C?C bond and two C?H bonds more than the previous alcohol. From my previous understanding and knowledge, I know that the first step in a reaction is the supply of energy to break a bond between two atoms. Energy is only released to the surroundings when the new bonds are formed.
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Meaning that the enzyme can carry on and react with another molecule of substrate. Problems will occur when an enzyme is denatured this can happen because an enzyme is raised above a certain temperature this is because the substrates cannot bind to the active site anymore. What Will I do? In this experiment I will find out how the amount of an enzyme within a reaction will affect the reaction. In this experiment, I will be using hydrogen peroxide and the enzyme catalyse that can be found in places such as yeast, the liver and many plants.
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The products of the reaction between hydrochloric acid and the marble chips are calcium chloride, water and carbon dioxide. CaCO3 (s) + 2HCI (aq) CaCI2 (l) + CO2 (g) My prediction is that the higher concentration of the acid, the faster rate of reaction. This is because a higher concentration of acid will contain more acid molecules per a set volume than a low concentration solution. This means that they will be a higher chance of calcium carbonate molecules colliding with the hydrochloric acid molecules and reacting.
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All possible causes of static electricity should be checked to prevent build-up and discharge and to make sure the equipment is secured to the floor to ensure it is grounded. All flammable liquids will need to be secured in an area where no sources of ignition can be located. It is also helpful to understand the terms which will be used to describe their chemical properties. When stored all information about the flammable liquids needs to be noted these would include the flash point, flammable range, Ignition Temperature and Vapour Density.
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The disadvantage was that it had to stop every ten to fifteen minutes to build up its steam power and it could only go at two and a half miles per hour. The steam engine and the boiler were separated from the other parts of the vehicle and were put on the front of the automobile which gave it a very ugly design and the steam engine was very heavy as well. This vehicle needed forty-five minutes to start and had no gear shifting.
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The distance between the bottle cap and the Coke can should be as close as possible (BUT the wick should not touch the bottom of the can and its burning should not be interrupted) to reduce heat loss. 2. The temperature of water should close to room temperature at initial, to avoid any extra heat loss to (or gain from) the surroundings, which may increase the percentage error. 3. The wick should be centered or it will be put off easily since the bottle cap absorb most of its heat.
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Investigation to compare quantitatively the concentration of reducing sugars in samples of fresh orange, lemon and grapefruit juice
The differences in colour mean that the Benedict's test is semi-quantitative, i.e. it can be used to estimate the approximate amount of reducing sugar in a sample. First of all, a range of colour standards is produced by preparing a series of glucose solutions of known concentrations. To an equal volume of each is added the same volume of Benedict's reagent and they are then heated in a water bath for the same length of time before being cooled to room temperature. An equal volume of an unknown sample is then treated in the same way and the colour compared with that of the colour standards.
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Outline how the main pollutants are formed in vehicle engines and the environmental problems they cause. Explain why different types of vehicle engines produce different exhaust emissions
NOx is formed by reaction of nitrogen and oxygen in the air so is pretty much unavoidable. It can be reduced by decreasing the time that combustion occurs for and this is why airplane jet engines have become shorter in length over the years - a shorter combustion path through the engine will produce less NOx. A range of sulphur oxides (SOx), which will form sulphuric or sulphurous acid that will also contribute to acid rain. SOx are formed by reaction of sulphur in the fuel with oxygen in the air and can be avoided by using low-sulphur fuels. (iii)
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Relationship between the increasing length of the carbon chain and the enthalpy of combustion of the alcohol that contains the carbon chain.
The energy required to break a bond and the energy released when a new bond is formed is called the bond energy. These bond energies are always the same whether they are making or breaking bonds. Bonds made Bonds broken Bond type Bond energy kj/mol-1 Bond type Bond energy kjmol-1 C=O 805 C-O from coursewrok work info 336 O-H 464 O-H 464 C-H 413 C-C 347 O=O 498 These bond energy values in the above table are only averages. This is because not all atoms the same they contain the same number of protons but some contain different numbers of neutrons.
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is the change in length per unit length. When stress and strain are proportional they are obeying Hooke's Law. Tension ? extension or Stress ? strain The Elastic Constant or Youngs Modulus (E) is related to stress and strain as follows: Young's modulus is a fundamental property of a material which describes its stiffness, the ability to maintain its shape. A high Young's modulus value indicates that the material will not stretch by much under load. A Tensile Test is carried out to determine the properties, where a force is applied to a material of known length and uniform shape, in gradual increment noting the extension, the test load is applied until the material breaks.
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in it must have a lid on to stop the alcohol from evaporating * clamp this will hold the metal calorimeter in place and a specific distance * a stand to hold the clamp in position * A heat proof mat this will minimise and reduce the transfer of heat energy from experiment. Steps: ???????* You must gather all the requirements shown above. * Empty a place where you can carry out the experiment ???????* put your lab coat and goggles on for safety and protection for the eye and the clothes * Measure 200 cm3 of water using the
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The experiment would be unreliable and discredited. For example, a larger or small flame size will heat the water more or less, in the same time period, or the volume of water can change the temperature increase, as more or less molecules will need to be heated. Method * Weigh spirit burner * Measure 50cm3 of water in the measuring cylinder * Pour water into a copper beaker * Take water temperature * Place beaker into clamp, 15.5cm above the surface * Place spirit burner under the beaker and light the wick * (NOTE-The flame size should be about the same in each experiment.
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Fossil fuels are a non-renewable energy resource and will eventually run out. Fossil Fuels contain the products of photosynthesis of plants from millions of years ago but have lost much of their oxygen and are found as hydrocarbons. The Green House effect. Today scientists are concerned about global warming. The Earth and its atmosphere act like a green house - light from the sun hits the planet and changes into heat. The atmosphere surrounding the earth acts very much similar to the glass surrounding a green house with light passing through the atmosphere but not being able to leave as with a greenhouse.
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An exothermic reaction gives out energy to heat its surroundings while an endothermic reaction cools its surroundings by taking in energy. Bond enthalpy calculations can be used to give ?Hc Reactions involve bond breaking (which is an endothermic process) and then new bond making (which is an exothermic process). During an exothermic reaction the overall enthalpy of the reacting system decreases. This means that ?H is negative as energy from the reactants forming is transferred to the surroundings (air, test tubes, car engines, etc)
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We had four different alcohols, propan-1-ol, propan-2-ol, butan-1-ol and butan-2-ol. We soaked some mineral wool in the alcohols (not at the same time) and heated up the beaker of water with it until it went out. We had the starting temperature of the water before we did it and measured it when the flame had gone out. We decided to use 2mls of alcohol and 50mls of water. We chose to use these amounts because in our preliminary work we used 5mls of fuel, this took too long to burn.
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Their earliest form was that of a simple stone slab with incised parallel lines. The lines served to mark the place values. The earliest known counting table is from the island of Salamis in Greece. The latest surviving counting table is from the end of the 16th century and is in a museum at Strasbourg (Pullan 53). The only real difference between the early and later forms is the direction of the place value lines: horizontal or vertical. The medieval European form is the most well documented, in part because the English Exchequer only stopped using the counting table for tallying tax payments and the like in 1826 (Pullan, 27).
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Probably the most conductive container available for use in the classroom is a calorimeter. As well as not wasting energy in the heating of the container, I could also try to stop heat from escaping the top and edges of the container by covering it with a fitting lid. I will try to prevent the wind from blowing the flames to a different direction so all the windows must be shut. HYPOTHESIS More energy is released as more bonds are formed, below is the list of approximate energy required to break and form all bond involved in burning alcohols TYPE OF BOND ENERGY REQUIRED TO BREAK THE BOND (j)
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