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Drill: Draw LDDs for:

Drill: Calculate the volume of gas released at 227 o C under 83.1 kPa pressure when 320 kg of NH 4 NO 3 is exploded forming N 2 , O 2 , & H 2 O:. Drill: Draw LDDs for:. SCl 2 C 5 H 8 HSO 4 -1. CHM II HW. Complete the Take-Home Test attached to Poly’s website. Thermo-chemistry. Chm II.

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Drill: Draw LDDs for:

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  1. Drill: Calculate the volume of gas released at 227oC under 83.1 kPa pressure when 320 kg of NH4NO3 is exploded forming N2, O2, & H2O:

  2. Drill: Draw LDDs for: SCl2 C5H8 HSO4-1

  3. CHM II HW • Complete the Take-Home Test attached to Poly’s website.

  4. Thermo-chemistry

  5. Chm II PP-16

  6. Thermochemistry • The study of heat transfer in chemical reactions

  7. Thermo-chemical Terms

  8. Heat (H) • A form of energy that can flow between samples of matter

  9. Heat cannot be measured directly; thus, we measure heat change (DH)

  10. Enthalpy Change • Heat that can flow in/out of a system DH

  11. System • That part of nature upon which attention is focused

  12. Surroundings • That part of nature around the part upon which we are not focused

  13. Reaction Coordinate • A graph of energy change versus time in a chemical reaction

  14. P Energy R Time

  15. Exothermic Rxn • Chemical reactions that release, give off heat, or lose heat

  16. Exothermic Rxn • Products will contain less heat than the reactants DH < 0

  17. Endothermic Rxn • Chemical reactions that absorb, take in heat, or gain heat

  18. Endothermic Rxn • Products will contain more heat than the reactants DH > 0

  19. Thermochemistry Topics • Heat Change • Calorimetry • Thermochemical Equation

  20. Topic: Heat Change

  21. Specific Heat • The heat required to raise one gram of a substance 1oC • c: (J/goC, J/kgK)

  22. Specific Heat Formula DH = mcDT

  23. Heat of Fusion • The heat required to melt one gram of a substance at its normal MP • Hf: (J/g or J/kg)

  24. Heat of Fusion Formula DH = mHf

  25. Heat of Vaporization • The heat required to boil one gram of a substance at its normal BP • Hv: (J/g or J/kg)

  26. Heat of Vap. Formula DH = mHv

  27. Calculate the heat change when 10.0 g H2O goes from –100.0oC to 200oC.MP = 0oC BP = 100oCHf = 334 J/g HV = 2260 J/g cice = 2.06 J/gK cwater = 4.18 J/gK csteam = 2.02 J/gK

  28. Drill: Calculate the heat required to change 25 g of H2O from 140.0oC to 60.0oC MP = 0oC csteam= 2.02 J/gK BP = 100oC cwater= 4.18 J/gK Hf = 334 J/g cice= 2.06 J/gK HV= 2260 J/g

  29. Review Drill & Collect Tests

  30. CHM II HW • Review PP-16. • Complete the attached assignment & turn it in tomorrow.

  31. Topic:Calorimetry

  32. Calorimetry • A method to measure the experimental heat transfer in a system

  33. Calorimeter • Device used to measure heat transfer • A calorimeter is an adiabatic system • Experimental yield

  34. Adiabatic System • A system that exchanges zero heat with its surroundings DHsystem = 0

  35. DH (J or kJ) DH = q = the heat or enthalpy change in a system DHsys = SmcDTsysparts

  36. Calorimetry DHsystem = 0 DHsys = DHcal + DHrxn DHrxn = -DHcal (all parts) DHrxn = -mcDTcal (all)

  37. When Q reacts in a 1.5 kg calorimeter containing 2.5 kg water the temp changes from 22.50oC to 26.50oC.Calculate DHrxn. Cwater = 4.18 J/gK Ccal = 2.00 J/gK

  38. In expensive calorimeters, the mass is constant; thus, the mc can be calculated together as C (J/oC). DHrxn = -mcDTcal DHrxn = -CDTcal

  39. When X reacts in a 2.0 kg calorimeter containing 1.5 kg water, the temp changes from 22.5oC to 30.5oC. Calculate DHrxn. Cwater = 4.18 J/gK Ccal = 1.50 J/gK

  40. When Z reacts in a 1.0 kg calorimeter containing 2.0 kg water, DT = 30.5oC to 20.5oC. Calculate DHrxn. Cwater = 4.18 J/gK Ccal = 2.00 J/gK

  41. Drill: When 40.0 g NH4NO3 dissolves in 460.0 g water at 25.0oC, the temp. falls to 22.5.oC. Calculate the DHosoln for NH4NO3. Csoln = 4.00 J/gK

  42. Check Drill&Check HW

  43. CHM II HW • Review PP-16 • Complete the attached worksheet & turn it in tomorrow (Thermo-1)

  44. Topic:Thermochemical Equation (TCE)

  45. Thermo-chemical Equation Terms

  46. Heat of Reaction • The heat or enthalpy change of a chemical reaction DHrxn

  47. Typical Reaction • HCl + NaOH  NaCl + HOH

  48. Heat of Solution • The heat or enthalpy change when a substance is dissolved DHsoln

  49. Typical Ionization KCl  K+(aq) + Cl-(aq)

  50. Heat of Combustion • The heat or enthalpy change when a substance is burned DHcombustion

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