Enthalpy of Combustion Lab Report Essay

AimThe goal of the following experiment is to determine the henry dislodge of conflagration of grain alcohol when nonp aril mole of grain alcohol is displaceed completely with the encourage of a belief lamp for a period period of unity and a unity- half minutes.Backg beatSpecific fondness Capacity is the amount of kindle unavoidable to raise the temperature of 1g of a substance 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 standpointard enthalpy of blaze of fermentation alcohol is -1371 KJ/mol.ApparatusInstrument / Chemical1. Spirit lamp containing grain alcohol2. Copper Calorimeter3. Distilled Water4. Stop Watch (?0.01s)5. 1?50cm3 beakers6. Retort rise7. Digital Thermometer (?0.1)8. Digital Electronic Balance (?0.01g)9. Stirring rodmethod acting1. The mass of the kernel lamp containing fermentation alcohol is first situated accurately with the sustain of the digital electronic ba lance and is recorded as M1 (?0.01g).2. Then a copper calorimeter is interpreted and the mass of the empty calorimeter is first determined. Then the calorimeter is modify with distilled pissing and the mass of the calorimeter along with piddle is then recorded. The two readings ar then subtracted to determine the mass of the distilled weewee utilize in the observational surgical process with the help of the digital electronic balance and is recorded as M3 (?0.02g).3. Then the calorimeter containing the water is position on top of the retort stand and the digital thermometer is utilize to record the initial temperature of the water alone with the help of the digital thermometer and is recorded as T1 (?0.1).4. Then the spirit lamp is lit and is placed on top of the beaker below the retort stand in sight to maintain a steady position of the lamp underneath the calorimeter containing the distilled water.5. The spirit lamp is separately(prenominal)owed to burn for a fixed ti me period of one and a half minutes while the water in the calorimeter is continuously stirred apply the stirring rod after which the final temperature of the water in the calorimeter is measured with the help of the digital thermometer and is recorded as T2 (?0.1).6. After the stainless procedure the final mass of the spirit lamp containing ethanol is measured with the help of the digital electronic balance and is recorded as M2 (?0.01g).HypothesisThe given data-based procedure is hypothesised to be a highly heat-releasing reaction as when ethanol is burnt in air the reaction gives come forward efficiency in the form of heat. When the spirit lamp (ignited) is placed directly below the calorimeter containing water, the heat energy released will result in a rise in temperature in the distilled water in the calorimeter.Variablesa). Independent Variables1. The amount of ethanol dod in the experimental procedure is an independent variable. In each of the cardinal runnels, the amount of ethanol used differs and this helps in providing a variety of results and make the experiment more accurate.2. The calorimeter in which the distilled water has been placed for each streak in the experimental procedure is an independent variable. This has been revisiond for each trial run in order to provide more accuracy to the experiment.3. The mass of the distilled water used in the experimental procedure is an independent variable. This has also been changed for each trial in order to provide a variety of results and superlative 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 the mass of water will also change depending on the amount of ethanol used.c). Controlled Variables1. The time for which the measured mass of distilled water is heated is kept constant as one and a half minutes byout the experimental procedure. This is done to provide an accurate experiment.2. The entire experiment is conducted in the same environment on the same mean solar day and in a secure room.3. The stopwatch used for each trial has also been kept constant throughout the experimental procedure.4. The thermometer used for each trial has also been kept constant throughout the experimental procedure.Observations1. The ethanol was burnt with a scandalmongering kindle.2. Some black soot was form on the bottom of the calorimeter after the spirit lamp was placed underneath it in the experimental procedure.3. It was mention that when the mass of the spirit lamp was noned in the scratch of the experiment, the lamp was not warm. However after the ethanol was burnt and the mass of the spirit lamp was once again being recorded, the lamp was warm at the end of the experiment.4. It was noted that while the spirit lamp was placed on the be aker perpendicularly below the calorimeter containing the distilled water, one could feel the warmth of the flame when one put out the flame after a period of one and a half minutes. stark naked datainitial mass of spirit lamp = M1,Final 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 following table N1 shows the raw data that has been recorded in order to determine the enthalpy change of conflagration of ethanol while conducting the following experimental procedureProcessed DataMass of ethanol that has been used and burnt completely = M1 M2 = MF,Rise in Temperature of the distilled water when the spirit lamp is placed directly below the calorimeter = T2 T1 = TF,The following fudge 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 v cases, submarine sandwich 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 burning A1 moles of ethanol = H2,Heat energy evolved by burning 1 mole of ethanol = H2/A1 = H3,Enthalpy change of combustion of ethanol =The following table N3 gives the processed data for the enthalpy change of combustion of ethanolSr. 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 sign of is negative. and then from the above five trials an average value of the enthalpy of combustion can be taken as the followingFair Test1. The experimental procedure is carried out in a safe 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 possible and with as much efficiency to avoid errors.3. The stopwatch is used accurately and was reset after each trial reading.4. go stirring the water alongside the experimental procedure one make sure that one did not disturb the digital thermometer in each possible way as even a small disruption could affect the temperature readings obtained.Safe Test1. One used safety spectacles and goggles while conducting the experiment to protect oneself from any chemical hazards.2. one time the time period of one and a half minutes has elapsed, the hoodlum of the spirit flame was placed over the wick of the spirit lamp with preciseness and safety.3. Before starting the experiment, one made a double tinkle about all the equipment being used in the experiment and whether the equipment is streamlined 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 AnalysisThe data booklet value for the standard 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 erect and cannot be accounted for by the uncertainties in the experimental measurements. The major uncertainties lie in the underlying assumptions used in the experimental procedure such as the following1. It is assumed that complete combustion of ethanol takes place. However the particular that when ethanol was being burnt in air, it b urnt with a yellow flame and the black soot on the calorimeter indicated that carbon, one of the products of incomplete combustion was also formed.2. It is assumed that all the heat from the reaction was transferred to the distilled water in the calorimeter. It is true that almost of the heat would have 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 absorbing any heat but in reality these instruments are also being heated.4. It is assumed that none of the ethanol escaped 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 the 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 turn out 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 Improvement / Evaluation1. There should not be any overthrow in the room where the experiment is being conducted as one is toilsome to prevent any interference to the internal system.2. While conducting the experiment, one should use a shield like device in order to cover the entire apparatus and prevent any heat transfer amidst the surrounding and the internal system.3. More efficient equipment should be used in the conducted experimental pr ocedure.