Energy Changes and Rates of Reaction

Thermochemistry
1. Energy Changes in Chemical and Nuclear Reactions
  1. The Nature of Energy
    1. Thermochemistry
    2. Energy
    3. Work
    4. Potential Energy
      1. Chemical Bonds
    5. Kinetic Energy
  2. Thermal Energy, Heat, and Temperature
    1. Thermal Energy
      1. More thermal energy=more movement
        Heat
        warm => cold
    2. Temperature
      1. increase as kinetic energy increases
  3. Law of Conservation of Energy
    1. universe divided into 2 parts
      1. Chemical system
        open
        propane BBQ
        closed
        glowstick
        isolated
        impossible to set up one on EARTH
      2. Surroundings
  4. Endothermic and Exothermic Reactions
    1. Exothermic
      1. products have lower potential energy
        stronger bonds
      2. energy added on the products side
    2. Endothermic
      1. products have a higher potential energy
        weaker bonds
        energy on the reactant side
  5. Nuclear Energy
    1. reactions all exothermic
      1. fusion
        release vast amounts of energy
        sun and star
        scientists try to create generators but it's hard due to the intense heat and pressure
      2. fission
        does not occur in nature
        elements above atomic number 83 are unstable and can undergo fission
        nuclear power plants use fission of uranium to produce electricity
2. Calorimetry and Enthalpy
  1. specific heat capacity
    1. water : 4.18 J/g*C)
  2. calorimetry and thermal energy transfer
    1. calorimeter
      1. well insulated reaction chamber
      2. tight fitting cover with insulated holes for a thermometer
      3. something to stir the calorimeter contents
      4. coffee-cup
      5. labratory
      6. bomb
      7. what to assume when using a coffee-cup calorimeter
        thermal energy transferred to outside or absorbed is negligable
        all dilute aqueous solutions have the same density and specific heat capacity as water
    2. total amount of thermal energy absorbed or released: q=mcΔT
      1. q+ =exo
  3. enthalpy
    1. +q = -H = exo
    2. to obtain molar enthalpy value: nΔHr
3. Bond Energy
  1. as the number of bonds increases the bond length shortends
    1. bond breaking=exo; bond making =endo
    2. more energy is needed to break multiple bonds than single
4. Hess's Law
Chemical Kinetics

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Energy Changes and Rates of Reaction

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	Erstellt von Vita Mishtii vor fast 11 Jahre