Heat of Formation of Magnesium Oxide

ObjetiveTo narrow down the wake up constitution of MgO (Magnesium Oxide) utilize Hesss Law, which states the shake up in spite of appearance a chemical reaction is freelance of the pathway between the initial and final examination states.IntroductionChemical reactions require stir up energy to complete, called an rut-absorbing reaction, or produce heat energy, and and thence called an exothermic reaction. The heat energy produced by such reactions after part be c beful victimisation a calorimeter, a adult male of equipment that can isolate the reaction in an insulated container. Using the calorimeter cardinal can then model the rise and fall in temperature of the reaction. When this temperature tack is multiplied by the heat efficiency, the amount of heat needed to shake up the temperature of a body by one degree, we can measure the change in converting our initial components (reactants) to their various(prenominal) products.In this experiment we entrust measu re the amount of heat released from 3 reactions (HA HB HC) and calculate the fit of all 3 reactions to determine HT, which will give us the heat organisation of MgO. If Hesss law holds true and proscribe minimal experimental error, the pathway we part to determine HT should ache no commission on our calculation matching the judge calculation of MgO.MethodsAs per lab manual we employ a calibrated calorimeter ( using a travel end thermometer so as to non puncture a hole in the calorimeter) to determine the heats of reaction for Magnesium (Mg) with Hydrochloric caustic (HCl) and Hydrochloric Acid with Magnesium Oxide (MgO). Then using mathematical formulas we were fit to calculate the heat constitution of MgO, which is measured in kJ/ mole. Since two reactions be in dilute body of urine system solutions ofHCl it was necessary to know the heat capacity of urine system, but because some heat would be transferred to the calorimeter whose heat capacity was unknown, we had to record a correction factor (x) based upon the special heat of pissing using the compare m(h2o)+XC pee+water=-1(m( folderol water)Cwatertice water).We then recorded the deal (m) of dwell temperature water and ice water each in a respective cup and then poured the ice water into the room temperature water and recorded the temperature change. By knowing (x) we could then calculate the heat of reaction for Mg with HCl (HA kJ/mol) and for HCl with MgO (HB kJ/mol) using the compare q=m(HCl+X)C T where m is the mass of the reactant used with Mg + X, C is the heat capacity of water (4.184 J/gC), and T is the total temperature change in each reaction. Using the results of these calculations and Hesss law we can then determine the heat formation for MgO.DataAll mass readings are granted in units of grams (g), and all temperature readings are given in degrees Celsius (C).Part AMass of the Calorimeter + RoomTemp irrigate (g)48.08Mass of room temp water (g)46.29Mass of Cal + room tem p water + icewater (g)115.40Mass of ice water (g)67.32Temp of room temp water (C)42.4Temp of the ice water (C)0.1Final temp. of room temp water (C)17.3Change in temp of ice water (C)17.2Change of temp of room temp water (C)-25.1Mass of the calorimeter (g)1.79Part 2AMass of Calorimeter (g)1.79Mass of Cal + HCl (g)103.55Mass of HCL (g)101.76Mass of Mg (g)0.5Temperature of HCl (C)20.3Final temperature of HCl + Mg (C)42.0Change in Temperature (C)21.7Part BMass of Calorimeter (g)1.79Mass of Cal + HCl (g)101.76Mass of HCl (g)99.88Mass of MgO (g)0.8Temperature of HCl (C)20.3Final temperature of HCl + MgO (C)25.8Change in Temperature (C)5.50Results and DiscussionTo calculate X using the equation m(h2o)+XCwater+water=-1(m(ice water)Cwatertice water) the vari able X moldiness be isolated and doing so we were than able to calculate the correction factorestablish on the calculations of the calorimeter correction factor, X was heady to be 0.158 g. Then using the equation q=m(HCl+X)C *T, where q is equal to the amount of energy given off, and than calculating the hold dear in -kJ/Mol (because these are exothermic reactions) we were able to determine HA and HB.qA=m(HCl+X)C xTqA=(101.76 g + 0.158 g) x 4.184 J/gC x 21.7CqA= 9250 J = 9.250 kJ 9.253602176qB= m(HCl+X)C xTqB=(101.76 g + 0.158 g) x 4.184 J/gC x 5.50CqB=2350 J = 2.350 kJTo then calculate the heat formation of MgO HT, the sum of all the reactions must be impelled including HC, the heat formation of water, which is already predetermined to be -285.8 kJ/mol. just to determine the proper equation for HT, the stoichiometric equations must first be equilibrateTherefore the heat formation of MgO was determined to be -618.35 kJ/mol. According to the textbook, the accepted value for HT=-601.8 kJ/mol. To determine the accuracy of the calculation we can determine the % errorAs distant as accuracy goes a share error of 2.75% is very acceptable. Because the methods of the experiment were conducted using a crude calorime ter I would bind birthed the percent error to be higher, assuming that because of its construction it would not have very high efficiency.I would expect that any error that might have occurred happened during the transference from one cup to another. Because the substances were transferred so quickly and taking into account the reckon of seconds that it took to replace the thermometer to begin preserve info again it is possible that energy was all lost in the transfer or energy was lost before the recording was actually able to begin.ConclusionIn this lab we were able to determine the heat of formation of MgO using a simply constructed calorimeter, which was found to be -618.35 kJ/mol.