Comparing The Enthalpy Change Of Combustion Of Different Alcohols :: GCSE Chemistry Coursework Investigation

Comparing The hydrogen Change Of Combustion Of Different AlcoholsThe aim of my experiment is to investigate the heat content of burningof a range of alcohols. The standard enthalpy of blaze is theenthalpy change that extends when 1 mole of a fuel is burned entirelyin oxygen under standard conditions 1 atmosphere blackmail and 298K.All combustion reactions are exothermic which is why I am expectingall the values for the enthalpy change of combustion to always benegative.Prediction==========I predict that the greater the number of carbon atoms at that place are in thealcohol molecule, the greater the enthalpy change of combustion itwill have. This is because in a chemical reaction readiness is necessary in enounce to break bonds and naught is released when bonds are make. If Iwere to pick up at these two values the energy required to break thebonds of the reactants and the energy released when the bonds of theproduct are made then I am qualified to work discover the enth alpy change ofcombustion of the alcohol. In order to do this we need to know thebong enthalpies of the bonds in the process. The quantity of energyneeded to break a particular bond in a molecule is called the bondenthalpy. Below is a table containing the bond enthalpies of the bondsthat occur in the combustion of an alcohol.BondsWe use the average bond enthalpies as the convey value of a bondenthalpy depends on the particular raise in which the bond isfound. GRAPHDH1By looking at the par for the reaction that occurs when analcohol burns, we realise that the reaction involves both breakingbonds and qualification new ones. From the equation of the process we cantell how many of the various number of bonds are disordered and made andso work come out of the closet the enthalpy change of combustion. We can work out theenthalpy of combustion of methanol by using the bond enthalpy valuesCH3OH + 1.5O2carbonic acid gas + 2H2OWe can use the enthalpy cycl e above to work out the value for theenthalpy change of combustion of methanol, represented by DH1. The calculation is done as shown belowDH2 = enthalpy change when bonds are broken= 3 E(C-H) + 1 E(C-O) + 1 E(O-H) + 1.5 E(O=O)= 3(413) + 358 + 464 + 1.5(498)= 2808 kJ mol-1DH3 = enthalpy change when bonds are made