Esters. Esters are formed from an alcohol and carboxylic acid; this is an example of esterification. I am going to write about the chemical reactions of when an ester is made, the ethics of animals used for testing cosmetics, what an emollient is and I w

Esters Introduction Esters are used in perfumes, cosmetics, and flavourings (mainly sweets). Esters are formed from an alcohol and carboxylic acid; this is an example of esterification. I am going to write about the chemical reactions of when an ester is made, the ethics of animals used for testing cosmetics, what an emollient is and I will write about the two practices we did for esters and the questionnaire I did asking people about animal testing and whether or not they agree with it. Theory I am going to write about Esters and examples, using animals to test cosmetics and how these are done and I will write about emollients. Esters are generally neutral, colourless liquids that have a fairly low boiling point. Many of them have pleasant smells, like sweets or fruity smells, they are also volatile this makes them ideal for perfumes as the evaporated molecules can be detected by smell receptors in your nose). However many esters are flammable or even highly flammable so their volatility makes them highly dangerous, esters don't mix well with water as they are more soluble in water than hydrocarbons, but not nearly as solouble as alcohols or carboxylic acids, although esters do mix well with alcohols and other organic solvents. Inhaling the fumes from some esters irritates mucous membranes in the nose and mouth. Ester fumes are heavier than air and very flammable, some

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  • Level: GCSE
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Hydrocarbons and the importance of oil as a power source.

Importance of OIL BY: Shivaans Doshii Grade: 9.1 Chemistry Essay PART 1 Fossil fuels are a source of energy that comes from once-living things. When living things die, they are broken down and covered by dust, soil or sand. As they are covered over by once-living things and by more layers of soil, sand and rock, they get buried deeper and deeper below Earth's surface. These layering of once-living things, sand and soil are eventually subjected to very high pressure and to very high temperature. When the pressure is great enough, the sand and soil change into rock. And at just the right temperature, the once-living things change into liquid called oil and a gas called natural gas. This oil and gas are found in porous rocks. Crude oil is separated into fractions by fractional distillation. The fractions at the top of the fractionating column have lower boiling points than the fractions at the bottom. The heavy bottom fractions are often cracked into lighter, more useful products. All the fractions are then processed further. The fractions at the top have a lower boiling point. The fractions at the bottom have a higher boiling point Some fractions from the distillation tower need to be transformed into new components. This is where a refinery

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Benzoic acid lab report

Result Compound Mass of a crude solid, g Mass of a recrystallized solid, g % Yield (For recryst-n step) Measured melting point, ? Reference melting point, ? Benzoic acid .1 .56 55% 20-128 22.4 Benzil .29 .56 43% 96-98 94.4 Mixture N/A N/A N/A 80-113 14 Table 1 The crude benzoic acid was a white powdery substance that weighed 1.1 grams. The pure benzoic acid that was recrystallized was white crystals weighing .56 grams. While the solution was cooling small crystals began to form in the solution. It was then vacuum filtered and white crystals were left in the filter and were weighed. % Yield= (Final mass/Initial mass) X 100% % Yield (Benzoic acid) = (.56/1.1) X 100%= 55% % Yield (Benzil) = (.56/1.29) X 100% = 43% Discussion In this lab, a mixture of two solids was separated to their individual components by extraction. The yields for benzoic acid (55%) and benzyl (43%) were both low. Because of solubility issues (difficulty dissolving all of the starting material) I know that some of the starting material never left the first flask. After the extraction of the benzoic acid and the benzil, I saw that the two solids were now in the original form we started with but they were now separate from each other. It was no longer conglomerate of both. Table 1 shows the percent recoveries of both substances were low and this could have resulted from the all

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  • Level: GCSE
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Which Alcohol is the Best Fuel?

Investigation - Which Alcohol is the Best Fuel? In my investigation, I will be trying to decide which alcohol is best to use as a fuel from a selection of five different choices. These are: - Methanol - Ethanol - Propanol - Butanol - Pentanol And to do so I will be using the following apparatus: Spirit burner with the respective fuel - Clamp - Tin can - 100cm3 of water - Thermometer - Polystyrene insulating lids - Stopwatch - Scales - Source of ignition such as matches I will be sure to use goggles in my investigation as a safety precaution. My method is as follows. Firstly, I will weigh and record the mass of each of the fuels named above. Then, I shall fill up the tin can with 100 cm3 of water, and place it in the clamp, directly above the fuel. I will also need to measure the temperature of the water. 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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GCSE Science Coursework

GCSE Science Coursework Title: Burning Fuels. What are you trying to find out? I will be carrying out an investigation, which allows me to calculate and compare how much energy/fuel is used to raise 100cmcubed of water to 20 degrees centigrade. I will be using 5 different fuels; Butanol, Pentanol, Propanol, Methanol and Ethanol. The aim is to find out how much energy is produced when burning these alcohols. Alcohol's react with oxygen in the air to form water and carbon dioxide. This is an exothermic reaction, meaning that when energy is put in, more energy is given off. The formulae of the alcohols that I will be using are. Methanol CH OH Ethanol C H OH Propanol C H OH Butanol C H OH Pentanol C H OH Prediction: I predict that the more bonds there are holding the carbon, oxygen and hydrogen atoms together; more energy will be required to break them apart. For example Ethanol has the formula C H OH. In this formula you have five C-H bonds, one C-C bond, one C-O bond and one O-H bond. To separate these types of bonds you require a certain amount of energy, which I will show in a table. C-H 410 C-O 360 O-H 510 O=O 496 C=O 740 C-C 350 To separate C-H bond you need to apply 410 joules of energy. There are five such bonds in ethanol so you multiply 410 by five to get 2050 joules. You do these calculations for all the other types of bonds that make up ethanol, add

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Alkanes and Alkenes

Unit 3 Notes Petrochemicals and fuels * Crude oil (petroleum) is made up of compounds, which are made of hydrogen and carbon, they are called hydrocarbons. * Carbon is aelement that has many different functions. It can join up to make chains, branched chains, and rings. * The properties of hydrocarbon depend on the size of its molecules groups. * Groups of molecules that have similar properties are known as homologous series. Homologous series and compounds * Organic compounds, which havea similar groups of atomsand have similar properties are called the homologous series of compounds. * Organic compounds have: . Have same general formulae 2. Similar characteristics 3. Show a gradual increase in physical properties such as m.p (melting point) and b.m (boiling point). Examples: Alkanes: . Saturated compounds (don't have double bonds) 2. Have no double bonds 3. React by substitution reactions * Some alkanes are methane, ethane, propane, and butane * General formulae of alkanes: CxH2x + 2 Alkenes: . Have double bonds 2. Made of carbon and hydrogen 3. Unsaturated (have double bonds) 4. React by addition reactions * Some alkenes are ethane, propene * General formulae of alkenes isCxH2x * More reactive than alkanes because of the double bond Refining oil * In order to be useful crude oil has to be refined Refining involves 3 stages: . Separation 2.

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  • Level: GCSE
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Investigation into the energy released by burning alcohols

Investigation into the energy released by burning alcohols Aim The aim of my experiment is to investigate how much energy is released by 5 different alcohols when they are burnt. These are Methanol, Ethanol, Propanol, Butanol and Pentanol. Scientific Theory In the following experiment I will be investigating how much energy is given off when you burn an alcohol. The 5 alcohols I will be investigating are methanol, ethanol, propanol, butanol and pentanol. All of these are part of the homologous series and so they all contain the functional group O-H. Their structures can be shown as follows: Therefore the general formula for alcohols is: When each of these fuels is burnt they are all exothermic, combustion reactions. A balanced combustion equation for methanol would be CH3OH + 11/2 O2 ? CO2 + 2H2O. A combustion reaction is when the fuel burns in the oxygen in the air producing carbon dioxide and water. The combustion equation can be used to work out the energy given off by using bond calculations. The reactions are exothermic because they give off energy to the surroundings and so the energy released that I work out will be a negative number. The heat energy released can be worked out from an equation. The equation is heat energy = vol of liquid x heat capacity (4.2) x temp change. Once this has been worked out you can find out the kJ/mol

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In this experiment, I plan to find out the difference in energy release between different sorts of alcohols. To do this I will test how much alcohol is required to increase the temperature of 100ml of water by 30 degrees Celsius.

Plan In this experiment, I plan to find out the difference in energy release between different sorts of alcohols. To do this I will test how much alcohol is required to increase the temperature of 100ml of water by 30 degrees Celsius. Obviously, many factors may affect my results, therefore making them less reliable. To improve my results, I will carry out some preliminary research to see if I can improve the reliability and accuracy. Please see attached preliminary work for details (sheet 2a). The preliminary work showed, in short, that it was beneficial to use an aluminium foil shield to reduce heat loss. I will set up my apparatus as shown below. To ensure my experiment is safe, I will sport goggles and comply with all of the normal laboratory requirements, such as not sitting on benches. To further my acknowledgement of safety, I will have to take care as one of the alcohols burns with a clear flame. I predict that, from observing my bond energy calculations (sheet 1a), the alcohol that will heat up the water in the least weight loss will be Butanol. This should be followed by Propanol, then Ethanol and finally, the alcohol that will grace us with most weight loss will be Methanol. This is also backed up by the secondary data I obtained from the data book. That is as follows: Methanol -715 kJ per mole Ethanol -1371 kJ per mole Propanol -2010 kJ per mole

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  • Level: GCSE
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If There Is a Relationship Between the Number of Carbon Atoms In Several Different Alcohols and the Heat of Combustion of Those Alcohols.

Planning Experimental Procedures Introduction In this experiment, I plan to discover if there is a relationship between the number of carbon atoms in several different alcohols and the heat of combustion of those alcohols. I would also like to discover the nature of the relationship(if there is one). For example: if the heat of combustion increases or decreases with the number of carbon atoms and by how much. Apparatus Retort stand, boss, clamp, tin can, water, six alcohols (methanol, ethanol, propanol, butanol, pentanol, hexanol.) in burners, Bunsen burner, heatproof mat, thermometer (0 - 100ºc), digital scales. Method . Set up the retort stand as shown above. 2. Record the starting temperature of the water (100ml). 3. Take the first alcohol - in a burner - and weigh it on digital scales. Record the weight. 4. Light the wick on the burner and allow it to burn until the temperature of the water in the can has risen by 20ºc. WEAR GOGGLES AS HEAT IS BEING USED! 5. Re-weigh the burner and record its new weight. 6. Calculate the change in weight since lighting. 7. Repeat steps 2 - 6 twice more. 8. Repeat steps 2 - 7 for each of the other alcohols. Variables and Constants My variable will be:- number of carbon atoms present in the alcohol being tested. My constants will be:- increase in temperature. volume of water to be heated. Preliminary Experiment We were

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Salters Open Book 2008 Fission and Fusion

Chemistry (Salters) Open Book 2008 Main differences between alpha and beta decay Alpha decay occurs when an unstable and heavy nucleus forms a more stable and lighter nucleus by disintegrating and emitting an alpha particle. (42? which is equal to 42He) This alpha particle contains two protons and two neutrons. Take for example 241Am, which is used in a smoke detector. The nuclear equation looks like this: 24195 Am 23793 Np + 42He Beta decay occurs when a neutron-rich isotope is changed into one with the atomic number one unit higher. This happens when a neutron is converted to a proton and electron. The electron is then released as Beta particle (0-1ß which means the same as 0-1e-) Take for example 23191Pa, the nuclear equation for Beta decay looks like this: 23191Pa 23192U + 0-1e- Due to the different events and reactions that occur, different products are formed. Here is a demonstration using 22588 Ra. ?-Decay 22588 Ra 22086 Rn + 42 He ß-Decay 22588 Ra 22589 Ac + 0-1e- Nuclear fission differs from natural radioactive decay. Radioactive decay and nuclear fission differ in many ways including the ways that the reactions must be started and the type of products that are formed. Radioactive decay has a lower energy barrier than fission and therefore is more common. Nuclear Fission involves the absorption of one neutron, whereas radioactive decay does

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  • Level: GCSE
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