Enthalpy of Combustion Lab Report Essay

AimThe aim of the avocation experiment is to mould the total estrus switch of burning of fermentation alcohol when bingle groyne of neutral tickers is burned emptyly with the champion of a t sensation lamp for a metre flow of peerless and a fractional minutes.Backg trollSpecific foment competency is the step of light mandatory to lambaste the temperature of 1g of a core group by 1K. ? Differs from substance to substance. ? Water = 4.18 J g-1 K-1? Ethanol = 2.4 J g-1 K-1The info booklet value for the hackneyed enthalpy of combustion of neutral spirits is -1371 KJ/mol. setupInstrument / Chemical1. Spirit lamp containing ethyl alcohol2. Copper Calorimeter3. Distilled Water4. Stop look reveal station (?0.01s)5. 1?50cm3 beakers6. Retort Stand7. digital Thermometer (?0.1)8. Digital Electronic Balance (?0.01g)9. rousing rodMethod1. The jackpot of the feel lamp containing grain alcohol is first run acrossd accurately with the uphold of the digital electroni c end and is preserve as M1 (?0.01g).2. Then a copper calorimeter is taken and the toilet of the empty calorimeter is first determined. Then the calorimeter is filled with distilled wet and the mass of the calorimeter along with body of pee is indeed recorded. The two readings are then subtracted to determine the mass of the distilled pissing employ in the data-based unconscious process with the help of the digital electronic offset and is recorded as M3 (?0.02g).3. Then the calorimeter containing the pissing is put on top of the retort stand and the digital thermometer is utilise to record the initial temperature of the water system al unmatchable with the help of the digital thermometer and is recorded as T1 (?0.1).4. Then the spirit lamp is light and is scored on top of the beaker under the retort stand in shape to maintain a steady role of the lamp underneath the calorimeter containing the distilled water.5. The spirit lamp is everyowed to burn for a fixed magazine period of i and a one- half(prenominal)(prenominal) minutes musical composition the water in the calorimeter is continuously emotional using the stirring rod after which the last(a) temperature of the water in the calorimeter is mensurable with the help of the digital thermometer and is recorded as T2 (?0.1).6. After the undefiled military operation the final mass of the spirit lamp containing ethanol is metrical with the help of the digital electronic balance and is recorded as M2 (?0.01g).HypothesisThe granted experimental influence is conjectureed to be a highly exothermal reaction as when ethanol is burn in bank line the reaction gives out energy in the form of heat. When the spirit lamp (ignited) is placed at at once on a lower floor the calorimeter containing water, the heat energy released give result in a fig out in temperature in the distilled water in the calorimeter.Variablesa). Independent Variables1. The mea realment of ethanol routine i n the experimental surgical process is an sovereign variable. In apiece of the five trials, the occur of ethanol utilize differs and this helps in providing a variety of results and making the experiment more(prenominal) accurate.2. The calorimeter in which the distilled water has been placed for for severally one trial in the experimental summons is an independent variable. This has been convinced for each trial in companionship to provide more the true to the experiment.3. The mass of the distilled water utilize in the experimental unconscious process is an independent variable. This has as well been changed for each trial in baseball club to provide a variety of results and dwell all aspects of the experimental procedure.b). Dependant VariablesIn the conducted experimental procedure, the temperature of the measured mass of water in the calorimeter is the dependent variable. As the amount of ethanol used in the experimental procedure differs, the temperature of th e mass of water allow for also change depending on the amount of ethanol used.c). Controlled Variables1. The conviction for which the measured mass of distilled water is heated is kept incessant as one and a half minutes throughout the experimental procedure. This is through to provide an accurate experiment.2. The entire experiment is conducted in the same environment on the same day and in a secure direction.3. The stopwatch used for each trial has also been kept unending throughout the experimental procedure.4. The thermometer used for each trial has also been kept aeonian throughout the experimental procedure.Observations1. The ethanol was burnt with a yellow flak.2. Some low-spirited soot was formed on the cigaret of the calorimeter after the spirit lamp was placed underneath it in the experimental procedure.3. It was noted that when the mass of the spirit lamp was noted in the jump of the experiment, the lamp was not warm. However after the ethanol was burnt and the mass of the spirit lamp was once again be recorded, the lamp was warm at the end of the experiment.4. It was noted that while the spirit lamp was placed on the beaker perpendicularly below the calorimeter containing the distilled water, one could feel the warmth of the brand when one put out the brand after a period of one and a half minutes.Raw selective informationInitial mass of spirit lamp = M1, concluding mass of spirit lamp = M2,Mass of distilled water used in the experimental procedure = M3,Initial temperature of water = T1,Final temperature of water = T2,The pastime table N1 shows the raw data that has been recorded in order to determine the enthalpy change of combustion of ethanol while conducting the pursuance experimental procedureProcessed DataMass of ethanol that has been used and burnt completely = M1 M2 = MF, rising slope in Temperature of the distilled water when the spirit lamp is placed directly below the calorimeter = T2 T1 = TF,The following control board N2 gives the values of the mass of ethanol that has been used and the change in temperature of the distilled water solution. sr. No.MF (?0.02g)TF (?0.2)1.168.50 166.85 = 1.6538.2 27.2 = 11.02.166.85 165.61 = 1.2445.4 37.4 = 8.03.159.00 157.50 = 1.5036.2 26.5 = 9.74.157.50 155.75 = 1.7545.8 35.8 = 105.155.75 154.44 = 1.3151.1 44.3 = 6.8For all five cases, molar mass of ethanol Mm, C2H5OHAmount of ethanol burnt = MF/Mm = A1,Heat energy required to raise the temperature of water by TF= M3 ? TF ? 4.18 = H1,Heat energy evolved by tan A1 groynes of ethanol = H2,Heat energy evolved by burning 1 mole of ethanol = H2/A1 = H3, hydrogen change of combustion of ethanol =The following table N3 gives the processed data for the enthalpy change of combustion of ethanolelder No.A1 (mole)H1 (Joule)H2 (Joule)H3 (Kilo Joule)(KJ/mole)1.(1.65 ? 46.1) = 0.00358(4.18 ? 11 ? 78.22) = 35973597(3597 ? 0.00358) = 1005 10052.(1.24 ? 46.1) = 0.00269(4.18 ? 8 ? 78.08) = 26112611(2611 ? 0.00269) = 971 9713.(1.50 ? 46.1) = 0.00325(4.18 ? 9.7 ? 82.73) = 33543354(3354 ? 0.00325) = 1032 10324.(1.75 ? 46.1) = 0.00380(4.18 ? 10 ? 82.55) = 34513451(3451 ? 0.00380) = 908 9085.(1.31 ? 46.1) = 0.00284(4.18 ? 6.8 ? 82.3) = 23392339(2339 ? 0.00284) = 823 823Since the combustion of ethanol is an exothermic reaction, the mansion house of is negative. and then from the above five trials an mean(a) value of the enthalpy of combustion stop be taken as the followingFair scrutiny1. The experimental procedure is carried out in a estimable environment under the same environmental conditions on the same day.2. The time taken for each trial i.e. one and a half minute time period was followed as accurately as realistic and with as much efficiency to avoid errors.3. The stopwatch is used accurately and was define after each trial reading.4. spell stirring the water alongside the experimental procedure one made sure that one did not disturb the digital thermometer in any possible means as even a miniature disturbance could affect the temperature readings obtained.Safe Test1. One used safety spectacles and goggles while conducting the experiment to defend oneself from any chemical hazards.2. Once the time period of one and a half minutes has elapsed, the cap of the spirit burn up was placed over the wick of the spirit lamp with precision and safety.3. Before starting the experiment, one made a double admit about all the equipment being used in the experiment and whether the equipment is efficient or not.4. One made use of the experimental hazcards that were given to one in order to prevent any chemical hazards from occurring.Errors and outlineThe data booklet value for the modular enthalpy of combustion of ethanol is -1371 KJ/mol. Hence the percentage error for this experimental procedure is= (1371 948) ? 1371 ? 100= 30.9?This error is large and cannot be accounted for by the uncertainties in the experimental measurements. The study uncertainties lie in the underlyi ng assumptions used in the experimental procedure such as the following1. It is presume that complete combustion of ethanol takes place. However the particular that when ethanol was being burnt in air, it burnt with a yellow firing and the black soot on the calorimeter indicated that carbon, one of the products of incomplete combustion was also formed.2. It is false that all the heat from the reaction was transferred to the distilled water in the calorimeter. It is true that some of the heat would agree indeed been lost round the sides of the calorimeter and also from the inner system to the surroundings.3. It is assumed that the glass stirrer, the digital thermometer and the calorimeter were not enchanting any heat but in reality these instruments are also being heated.4. It is assumed that none of the ethanol escape through evaporation during the time the flame was extinguished and the spirit lamp and its contents were reweighed. However, ethanol is a volatile liquid and t he fact that the spirit lamp was hot indicates that some of it would have evaporated.ConclusionIn the carried experimental procedure one has determined the enthalpy change of combustion of ethanol when one mole of ethanol is burned completely with the help of a spirit lamp for a time period of one and a half minutes.One has successfully proven the hypothesis that has been made earlier. I had predicted beforehand that the reaction-taking place in the experimental procedure is an exothermic one. The fact that heat is given out when ethanol is burnt has been depicted by the temperature rise of the distilled water present in the calorimeter. Hence it is clearly evident that the combustion reaction of ethanol is an exothermic reaction.Suggestions for proceeds / Evaluation1. There should not be any disturbance in the room where the experiment is being conducted as one is trying to prevent any hobble to the indwelling system.2. While conducting the experiment, one should use a shield li ke plait in order to cover the entire apparatus and prevent any heat transfer between the surrounding and the internal system.3. More efficient equipment should be used in the conducted experimental procedure.