2. Equilibria Flashcards
Kc = equilibrium constant =
[products]/[reactants]
4 characteristics of a dynamic equilibrium
- closed system
- constant temp
- constant pressure
- forward rate = backwards rate
effect the vaule of kc has
- above 1 its product favoured
- below 1 its reactant favoured
how temp changes kc
use le chateliers principles to figure out which was the equilibrium shifts
when does kc change
only with a change in temp
what causes the shift with pressure
the neeed to restor kc
Fastors that effwect rate?
catalyst.pressureconcentrationsurface areatemperature
What is rate of reaction?
rate= change in concentration/time.
Catalys examples?
iron in the haber process.vanadium (5) oxide in the contact process.Ni in hydration of margarine.
Define catalyse.
speeds up rate by providing an alternate reaction pathway with a lower activation energy.isnt used up in the reaction.may form an intermediate.
Economic importance of catalysts?
made more quickly and easily.requiring less energy- cuts fuel cost.reduces waster as a different reaction may now be possible which have better % yield and atom economy.
what is a homogeneous catalyst?
in the same physical state as the reactants.
what is a heterogeneous catalyst?
in a different state to the reactants.
Define dynamic equilibrium.
the equilibrium that exists in a closed system when the rate of the forward reaction = rate of the backwards reaction.
Where are catalyst naturally found?
as enzymes.
Why use enzymes in industry?
lower temps and pressures can be used.usually pure products are formed- so no separation is needed.Are biodegradable (other ones are toxic) so are easy to dispose.
2 uses of enzymes as a catalyst.
fermentationwashing powders.
what is le chateliers principle?
that when a system is in dynamic equilibrium and is subject to a change, the equilibrium position will shift to minisise it.
