1.6 Equilibria Flashcards
what is the definition of dynamic equilibria
when forward and backward reactions occurs simultaneously
what are the two features of dynamic equilibria
- the forward and backward reaction occur at equal rates.
- the concentrations of reactants and products stay constant
what is a closed system
where no reactants or products can escape
what is Le Chatelier’s principle
if a system at equilibrium is disturbed, the equilibrium shifts to oppose the change
what is the effect of temperature on equilibrium
if temp increases the equilibrium will shift to oppose the change and move in the endothermic direction, to decrease the temp.
if temp decreases the equilibrium will shift to oppose the change and move in the exothermic direction, to increase the temp.
what is the effect of pressure on equilibrium
increasing pressure will cause the equilibrium to shift to the side with the fewest molecules to oppose the change, reducing the pressure
decreasing pressure will cause the equilibrium to shift to the side with the most molecules to oppose the change, increasing the pressure
*the position of equilibrium doesn’t change when there is an equal number of moles on both sides.
what is the effect of concentration on equilibrium
increasing the conc of the reactants causes equilibrium to shift to oppose the change and move to the right, favouring the forward direction decreasing the conc of the reactant. ( and vice versa)
what is the effect on catalysts on equilibrium
a catalyst has no effect on the position of equilibrium, but it will increase the rate at which equilibrium is achieved.
the haber process
N2 + 3H2 = 2NH3
T= 450c P= 200 - 1000 atm
iron catalyst
production of methanol
CO + 2H2 = CH3OH
T= 400c P = 50 atm
chromium and zinc oxide catalyst
production of ethanol
C2H4 + H2O = C2H5OH
T = 300c P = 70atm
conc H3PO4 catalyst
equation for the equilibrium constant
Kc = [C]^c [D]^d / [A]^a [B]^b
(the square bracket representing concentrations)
what is a homogeneous reaction
where all the reactants and products are the same physical state.
what is the heterogeneous reaction
where the reactants and products have different physical states.
what is the only condition which affects the value of Kc
temperature
