1 / 11

Bell Ringer

Bell Ringer. 2NO(g) + O 2 (g) 2NO 2 (g) D H = -27 kcal. Which graph represents the reaction shown above?. A. B. Energy. Energy. Reaction Progress. Reaction Progress. C. D. Energy. Energy. Reaction Progress. Reaction Progress.

benjamin
Download Presentation

Bell Ringer

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Bell Ringer 2NO(g) + O2(g) 2NO2(g) DH = -27 kcal Which graph represents the reaction shown above? A B Energy Energy Reaction Progress Reaction Progress C D Energy Energy Reaction Progress Reaction Progress Source: 2004 VA Chemistry EOC Exam

  2. Homework Answers • A, B • B • C • B • A • C • Inter • Intra • Dispersion forces • Boiling Point • Amorphous • Higher • Dipole-dipole • Freezing • Hydrogen bonding • 30ºC • 1.0 atm • 40ºC • 47ºC • 0.4 atm

  3. Practice with Enthalpy Calculate DH for the following reactions: 2 KBr (s) + I2 (g) 2 KI (s) + Br2 (l) DHtotal = [2mol (-327.9 kJ/mol) + 1mol (0 kJ/mol)] - [2mol (-393.8 kJ/mol) + 1mol (0 kJ/mol)] DHtotal = 131.8 kJ ENDOTHERMIC 2 HCl (g) + 2 Ag 2 AgCl (s) + H2 (g) DHtotal = [2mol (-127.01 kJ/mol) + 1mol (0 kJ/mol)] - [2mol (- 92.31kJ/mol) + 2mol (0 kJ/mol)] DHtotal = -69.40 kJ EXOTHERMIC

  4. Entropy and Gibb’s Free Energy They work the same way!! “PRODUCTS – REACTANTS” DStotal = DSproducts - DSreactants at 298 K! DS > 0, entropy increases (more disorder) DS < 0, entropy decreases (less disorder) DGtotal = DGproducts - DGreactants at 298 K! DG > 0, not spontaneous DG < 0, spontaneous DG = 0, equilibrium

  5. How do H, S, and G Relate? not at 298 K! DG = DH - TDS Potassium bromide reacts with iodine at 345K. Will this reaction occur spontaneously? 2 KBr (s) + I2 (s) 2 KI (s) + Br2 (l) DHtotal = [2mol (-327.9 kJ/mol) + 1mol (0 kJ/mol)] - [2mol (-393.8 kJ/mol) + 1mol (0 kJ/mol)] DHtotal = 131.8 kJ DStotal = [2mol (106.3 J/mol K) + 1mol (152.21 J/mol K)] - [2mol(95.9 J/mol K) + 1mol (116.14 J/mol K)] DStotal = 56.87 J/ K

  6. 1000 J x 1 kJ How do H, S, and G Relate? DG = DH - TDS Potassium bromide reacts with iodine at 345K. Will this reaction occur spontaneously? 2 KBr (s) + I2 (s) 2 KI (s) + Br2 (l) DHtotal = 131.8 kJ = 131,800 J DStotal = 56.87 J/ K DG = 131,800 J – (345K)(56.87 J/K) DG = 131800 J – 19620.15 J DG = 112179.85 J 112,000 J = 112 kJ NOT SPONTANEOUS!

  7. Properties of Water Ms. Besal 3/24-27/2006

  8. Characteristics of Water O H • Bent Shape • Hydrogen Bonding • Liquid at Room Temperature • Requires great amount of energy to change (raise or lower) temperature • Expands as a solid • High boiling point • High surface tension • High heat of vaporization • “universal” solvent H

  9. How does the flow of heat change water? E GAS DHvap = 40.7 kJ/mol VAPORIZATION 100ºC D CONDENSATION C TEMP. LIQUID MELT 0ºC B DHfus = 6.02 kJ/mol A FREEZE SOLID TIME

  10. Phase Diagram of Water E B FREEZE C liquid pressure solid CONDENSATION MELT VAPORIZATION . A gas D SUBLIMATION DEPOSITION Tc temperature

  11. E B liquid solid C . pressure A D gas temperature A: Triple point – the temperature and pressure at which gas, liquid, and solid form of a substance all exist in equilibrium. B: Melting curve C: Vaporization curve D: Sublimation curve E: Critical point – the temperature and pressure above which gas cannot be liquefied no matter how much pressure is applied.

More Related