IB Chemistry on Hess's Law, Calorimetry, Enthalpy Change of reaction for MgSO4 and KHCO3

• 1. Video Tutorial on Hesss Law, Calorimetryand Enthalpy change of reaction for MgSO4and KHCO3. Prepared by Lawrence Kok http://lawrencekok.blogspot.com

2. Video on Calorimetry and Hesss LawCalorimetry for MgSO4 Calorimetry using polystyrene cup Detail tutorial on heat capacityCalorimetry tutorial Calorimetry calculation 3. Energetics ( Enthalpy Change )Enthalpy Heat content of a system stored as chemical energy in chemical bondsBond Making Heat energy given off/releasedBond Breaking Heat energy taken in /absorbed During bond making + bond breaking certain amount energy is either ABSORBED or RELEASED 4. Hesss LawH = Enthalpy ( Heat Content )H = Enthalpy change ( Change in heat content )Hesss Law overall heat change of a chemical rxn is independent of its pathway energy change in changing A + B C + D is the same regardless of theroute (independent of route) by which the chemical changes occurs.Energy Level or Energy Cycle Diagram can be used to determine H 5. Hesss Law used to calulate H for rxn which cannot be determined experimentallyEx 1 Cal H for C(s) + 1/2O2(s) CO(g) which cannot be determined experimentally Energy Level 6. Hesss Law used to calulate H for rxn which cannot be determined experimentallyEx 1 Cal H for C(s) + 1/2O2(s) CO(g) which cannot be determined experimentally Energy Level or Energy Cycle Diagram Answer = -111kJmol-1 7. Hesss Law used to calulate H for rxn which cannot be determined experimentallyEx 2 Cal H for 2NO2(g) N2O4(g) H cannot be determined experimentally Energy Level 8. Hesss Law used to calulate H for rxn which cannot be determined experimentallyEx 2 Cal H for 2NO2(g) N2O4(g) H cannot be determined experimentally Energy Level or Energy Cycle Diagram Answer = -24 kJmol-1 9. Hesss Law used to calulate H for rxn which cannot be determined experimentallyEx 3 Cal H for NH3(g) + HCI (g) NH4CI (aq) which cannot be determine experimentallyUsing Energy Level DiagramAnswer = -159.8 kJmol-1 10. Hesss Law used to calulate H for rxn which cannot be determined experimentallyEx 3 Cal H for NH3(g) + HCI (g) NH4CI (aq) which cannot be determine experimentallyUsing Energy Cycle DiagramAnswer = -159.8 kJmol-1 11. Experiment on determining Enthalpy of reaction for MgSO4 (s) + 7H2O MgSO4.7H2O 12. Experiment on Enthalpy of reaction for MgSO4 (s) + 7H2O MgSO4.7H2O Cal H for MgSO4 (s) + 7H2O MgSO4.7H2O(s) cannot be determine experimentallyProcedure : To prevent heat loss to surrounding, expt was done using a double polystyrene cup with a lidEnergy Cycle for MgSO4 (s) + 7H2O MgSO4.7H2O 13. Determination of MgSO4 (s) + H2O MgSO4(aq) can be determine experimentally1 14. Determination of MgSO4 (s) + H2O MgSO4(aq) can be determine experimentally12 Data Collection 15. Determination of MgSO4 (s) + H2O MgSO4(aq) can be determine experimentally12 Data Collection3 Result 16. Determination of MgSO4.7H2O (s) + H2O MgSO4(aq) can be determine experimentally1 17. Determination of MgSO4.7H2O (s) + H2O MgSO4(aq) can be determine experimentally12 Data Collection 18. Determination of MgSO4.7H2O (s) + H2O MgSO4(aq) can be determine experimentally12 Data Collection3 Result 19. ResultsError Analysis and Improvements 20. Experiment on determining Enthalpy of reaction for KHCO3(s) K2CO3(s) + CO2 + H2OKHCO3 21. Experiment on Enthalpy of reaction for KHCO3(s) K2CO3(s) + CO2 + H2OCal H for KHCO3(s) K2CO3(s) + CO2 + H2O cannot be determine experimentallyProcedure : To prevent heat loss to surrounding, expt was done using a double polystyrene cup with a lid KHCO3Energy Cycle for KHCO3(s) K2CO3(s) + CO2 + H2O 22. Determination of KHCO3 + HCI KCI + CO2 + H2O can be determine experimentally1 23. Determination of KHCO3 + HCI KCI + CO2 + H2O can be determine experimentally12 Data Collection 24. Determination of KHCO3 + HCI KCI + CO2 + H2O can be determine experimentally12 Data Collection3 Result 25. Determination of K2CO3 + 2HCI 2KCI + CO2 + H2O can be determine experimentally1 26. Determination of K2CO3 + 2HCI 2KCI + CO2 + H2O can be determine experimentally12 Data Collection 27. Determination of K2CO3 + 2HCI 2KCI + CO2 + H2O can be determine experimentally12 Data Collection3 Result 28. ResultsError Analysis and ImprovementsH expt = +89.2 kJmol-1H lit= +95.3 kJmol-1% Error = (95.3 89.2)/95.3 %= 6.4% (Error) KHCO3 29. Video on Calorimetry and Hesss LawCalorimetry for MgSO4 Calorimetry using polystyrene cup Detail tutorial on heat capacityCalorimetry tutorial Calorimetry calculation 30. Video on Energetics and Enthalpy CalculationEnthalpy of reaction using combustion dataEnthalpy of reaction using combustion dataEnthalpy of reaction using formation dataGibbs Free Energy of reaction 31. AcknowledgementsThanks to source of pictures and video used in this presentationThanks to Creative Commons for excellent contribution on licenseshttp://creativecommons.org/licenses/Prepared by Lawrence KokCheck out more video tutorials from my site and hope you enjoy this tutorialhttp://lawrencekok.blogspot.com