To Determine the Heat of Formation of Calcium Carbonate Essay Example for Free

To Determine the Heat of Formation of Calcium Carbonate EssayA) In the 1st part, an accurately weighed known mass of anhydrous atomic number 12 sulphate(VI) powder is added to known volume of deionized body of water. With the process of the data of temperature agitate during the addition, the molar enthalpy change of solution of anhydrous magnesium sulphate(VI) can be calculated. ( H1)B) In the 2nd part, an accurately weighed known mass of magnesium sulphate(VI)-7-water powder is added to known volume of deionized water. With the sustain of the data of temperature change during the addition, the molar enthalpy change of solution of magnesium sulphate(VI)-7-water can be calculated. ( H2) later that, by constructing a suitable enthalpy cycle, i.e.MgSO4(s) + 7H2O(l) MgSO4 . 7H2O(s)MgSO4(aq)and applying Hesss law, the molar enthalpy change of hydration of magnesium sulphate(VI) ( H) can be calculated. ( H = H1 H2)5) DataAnhydrous MgSO4(s)MgSO4(s)-7-waterMolar mass / g mol-1120 .4246.4Mass of copper(II) sulphate / g3.016.16initial temp. of water / oC (T1)2524Highest/Lowest temp. attained / oC (T2)3422.5Change in temperature / oC (T2-T1)+9-1.5 spate of deionized water used 100 cm36) CalculationThe molar enthalpy change of solution of anhydrous magnesium sulphate(VI)= mc T x (no. of mol)-1= (100 x 4.2 + 3.21 x 1.3) x (-9) x (0.025)-1= -152.70 kJ mol-1The molar enthalpy change of solution of magnesium sulphate(VI)-7-water= mc T x (no. of mol)-1= (100 x 4.2 + 3.21 x 1.3) x (1.5) x (0.025)-1= 25.45 kJ mol-1By Hesss law, H = H1 H2= -178.15 kJ mol-1The molar enthalpy change of hydration of magnesium sulphate (VI)= -178.15 kJ mol-1Discussion(1)(3) is answered above4) What assumption consecrate you made in your calculation?Assumed* The thermal capacity of the beaker is negligible.* The specific come alive capacity of the 2 resulting solutions ar the same as water, and they also weight 1 g/cm3* The weight of the solids which dissolved in deionized water does not affect the total mass of the solution.* The solids are in pure state.* The solid are dissolved quickly so that the heat losses are negligible.* The resulting solutions were infinitely diluted, that is further addition of water would not cause any further heat change.* There was no heat lost to surround in 1st part and no heat gained in 2nd part.5) What are the sources of error in this experiment?* The specific heats of the solutions cannot be exactly 4.2 J g-1 oC-1 as that of water. The error could be minimized by victimisation electrical compensation method.* The solid night not be in pure state, that was, the anhydrous magnesium sulphate(VI) may be completely anhydrous, which could be improved by heating the sample for several(prenominal) hours in an oven and then use immediately.* Some solid might not dissolve quickly sufficiency and thus heat was lost. The improvement was using the reactants in powder form or tiny quartz glass form abut not bigger one, such that they could be dissolved quickly enough.* Some heat might e lost to 1st part or gained in 2nd part. The improvement was sequestrate the beaker or use a vacuum flask calorimeter.6) Why cannot the molar enthalpy change of hydration of magnesium sulphate(VI) be measured directly in the laboratory?Because it was not possible to form magnesium sulphate(VI)-7-water from anhydrous magnesium sulphate(VI) and water because the anhydrous saly may dissolved in water instead.ConclusionBy using the experimental result, the molar enthalpy change of hydration of magnesium sulphate(VI) is -178.15 kJ mol-1