An Investigation into the Enthalpies of the Combustion of Alcohols Essa

An Investigation into the Enthalpies of the Combustion of Alcohols==================================================================PlanningMy aim for this experiment is to see the zilch produced fromdifferent alcoholic drinks. This investigation involves burning alcohol in theair. GCSE Chemistry by B.Earl and L.D.R Wilford says that alcoholsform, another homologous series, with the general formula Cn H2n+1OH. The alcohol reacts with the oxygen in the air to form the productswater and carbon dioxide.This response is exothermic, as affectionateness is given turn out. This is because theamount reactant energy is more than the product energy the differencebetween this is H, therefore some energy has been given out in theform of heat. The energy is given out when forming the bonds betweenthe new water and carbon dioxide molecules. This can be shown in anenergy level diagram Reaction co-ordinate H is the heat content,which is the enthalpy, which is negative in exothermic reactions a sthe diagram shows that energy is lost as heat. Enthalpy is definedas the energy of reaction, or the heat energy associated with achemical change. For any reaction carried out directly at a constantpressure, the heat flow is hardly equal to the difference betweenenthalpy of products and that of the reactants.To measure the heat energy given off, we must use this energy to heatsomething, this pull up stakes be water. This is presume that all the heatproduced by combustion of the alcohol will equal the amount of heatabsorbed by the water (q). So I will measure the amount of energyrequired to do so. This can be worked out by apply the formula q =mass x specific heat capacity x temperature rise or q = MCH. Where qis the quantity of heat. The specific heat capacity is the amount ofenergy required to heat the substance, and is calculated using theformula q =energy supplied/ Mass x Temperature, where q is theenthalpy, c is the specific heat capacity and H is the temperaturerise. I chos e to use water as it is safe, easily obtainable, and has aconstant, reliable specific heat capacity of 4.2J/C.The bonds which are made in a exothermic reaction are forces ofattraction between the atoms or ions in a substance. These can be oftwo types covalent, in which the atoms share electrons. Examples ofthis are water and carbon dioxide, whi... ...lowtemperature reading to heat the 100cm3 of water.The procedure of the experiment was good plenty of finding out theenergy gained from the individual alcohols, but changes could havebeen made to make the reliability of the results more accurate. Thiscould have been done by using a better and more accurate thermometer,such as an electric thermometer, which have gave me a much more pinpoint set of results.If I were to do this experiment again I would make a number ofimprovements or changes, I could use a Bomb Calorimeter whichsubmerges the reaction inside an insulated container of water. Anelectrical thawing device starts the reaction inside a sealed reactionvessel and the temperature rise of the water which surrounds it ismeasured. Bomb calorimeters are often used to find the calorific valueof foods.Looking at the experiment I did I thought we could have extended theresults we achieved by using different flame lengths, this would havetold us how much the alcohol uses its energy when the flame isincreased. I could have also changed the amount of water in the coppercalorimeter, or even change the immersion of alcohol to see theeffect.