Physical 1: Equilibria Flashcards
define the term dynamic equilibrium
the rate of the forward reaction is equal to the rate of the reverse reaction - so the concentrations of reactants and products do not change
give an essential condition for an equilibrium mixture
- equilibrium occurs in a closed system
OR - macroscopic properties do not change with time
state Le Chatelier’s principle
if a system at equilibrium is disturbed, the equilibrium moves in the direction that tends to reduce the disturbance
what effect would increasing the temperature have on the position of equilibrium?
the equilibrium position shifts to the endothermic reaction
what effect would increasing the pressure have on the position of equilibrium?
equilibrium shifts to the reaction which produces the least moles of gas
suggest and explain why an industrial chemist may use a high pressure for the production of hydrogen from:
CH4(g) + H2O(g) -> CO(g) + 3H2(g)
- high pressure increases the collision frequency, increasing the rate of reaction
- this is a compromise pressure between an economically viable rate of reaction and a slightly lower yield of hydrogen
what effect does a catalyst have on the position of equilibrium?
no effect because catalysts affect rate of forward and reverse reactions equally
what condition affects the value of Kc?
temperature
what type of system is Kc relevant for?
homogenous systems in equilibrium
what does Kc being greater or lesser than 1 suggest for the position of equilibrium?
greater than 1 = over to the right
lesser than 1 = over to the left
what effect does increasing the temperature in an endothermic reaction have on Kc?
Kc increases
what effect does decreasing the temperature in an exothermic reaction have on Kc?
Kc increases
what effect does increasing the temperature in an exothermic reaction have on Kc?
Kc decreases
