Equilibrium

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  • n2 and H2 <-->2MH3 naCl(s)--> NaCl(aq)
  • temp concentration pressure surfce are catalysr/inhibitor--only gets you threr faster or slower
  • teeter totter--add to one side the other goes up Safti-shift away from the increase
  • Equilibrium

    1. 1. Equilibrium
    2. 2. • A state of rate balance between twoopposing changes• types of equilibrium1. reaction equilibrium--rate of synthesis = rate of decomposition2. solution equilibrium(takes place in a saturated solution)--rate ofdissolving = rate of precipitating3. phase equilibrium--rate of melting =rate of freezing (at the freezingpoint) or rate of boiling = rate of condensing (at boiling point)
    3. 3. properties of a system at equilibrium• 1. since equilibrium is a rate balance, anything that might change reaction ratemust be kept out of the system or the eq will be ruined.The system must beclosed.1. temp and pressure2. don’t change the conc.--no more reactant, don’t let any productescape• 2. A system at equilibrium with stay that way forever• 3. Equilibrium is dynamic (its always in motion)• 4. delta G at equilibrium = Zero
    4. 4. stressing the equilibriumLe Chatelier’s Principle• Factors affecting equilibrium• Predicting the direction of the shift• Predicting resulting change in concentration• Making equilibrium serve your own evilpurposes
    5. 5. Factors Affecting Equilibrium• Equilibrium is a rate balance• anything that affects one of the reactionscan throw the equilibrium off1.2.3.4.5.
    6. 6. Using Le Chatelier• Stress--add or remove a reactant.Add or remove aproduct• Shift-- the reaction will shift away from what isadded and towards what is being removed• Change in conc. the conc. of what is being shiftedtoward increases.The conc. of what is being shiftedaway from decreases
    7. 7. concentration• If a reactant is added:1. the number of collisions between reactant particles increases2. the rate of the forward reaction increases (forward shift)N2 + 3H2 <--> 2NH3 + heat• If a product is added:1. the number of collisions between product particles increases2. the rate of the reverse reaction increases (reverse shift)N2 + 3H2 <--> 2NH3 + heatStress--Shift--Change in Conc.
    8. 8. concentration• If a reactant is removed:1. the number of collisions between reactant particles decreases2. the rate of the forward reaction decreases (reverse shift)N2 + 3H2 <--> 2NH3 + heat• If a product is removed:1. the number of collisions between product particles decreases2. the rate of the reverse reaction decreases (forward shift)N2 + 3H2 <--> 2NH3 + heatStress--Shift--Change in Conc.
    9. 9. temp and EQ• If temp is increased1. the eq will shift in the endothermic direction (converting the excess KE to PE2. the endothermic direction is away from the side with the heat (kJ)N2 + 3H2 <--> 2NH3 + heat• If temperature is decreased1. the equilibrium will shift in the exothermic direction (releasing PE to make upfor the lost KE)2.The exothermic direction is towards the side with the heatN2 + 3H2 <--> 2NH3 + heat
    10. 10. pressure and EQ• If pressure is increased1. the eq will shift to the side with the fewer moles of gas to bring the pressuredownN2(g) + 3H2(g) <--> 2NH3(g) + heat• If pressure is decreased1. the equilibrium will shift toward the side with more moles of gas to bring thepressure back upN2(g) + 3H2(g) <--> 2NH3(g) + heat

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