Equilibrium

    Cards (15)

    • Many reactions are reversible and exists in a state of equilibrium.
    • In a dynamic equilibrium, both the forward and reverse reactions occur at equal rates.
    • At equilibrium, there is no change in the concentration of reactants or products.
    • Homogeneous equilibrium

      All reactants and products are present in one phase
    • Heterogeneous equilibrium

      Reactants and products are present in more than one phase
    • A catalyst increases both the rate of forward and reverse reaction equally. Hence, there is no effect on the equilibrium position or KcK_c
    • Equilibrium constant formula
      aA+aA+bBcC+bB\rightleftharpoons cC+dDdD
      Kc=K_c=[C]c[D]d[A]a[B]b\frac{[C]^c[D]^d}{[A]^a[B]^b}
    • The equilibrium constant is only affected by temperature.
    • What affects the equilibrium position?
      • Change in concentration
      • Change in pressure (only if in gaseous state)
      • Change in temperature
    • Effect of conditions on equilibrium
    • Le Chatelier's principle
      If a dynamic equilibrium is disturbed, the equilibrium position shifts to counteract the change and establish a new equilibrium.
    • If the concentration of a reactant is increased, the forward reaction will be favored to counteract this. Vice versa.
    • Kc (reverse)K_{c\text{ (reverse)}}==1Kc (forward)\frac{1}{K_{c\text{ (forward)}}}
    • A small KcK_c value (KcK_c<<11) implies that reactants are favored over products.
    • A large KcK_c value (KcK_c>>11) implies that products are favored over reactants.
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