Equilibrium Flashcards
What is a dynamic equilibrium?
A reaction that is continuously occurring forward and backwards, rates forward and backwards are equal
Equilibrium for reactions
All reactions are equilibrium, just that some go almost fully to completion. Equilibrium does not mean equal amounts, but rates
Equilibrium in solutions
With a saturated solution, no ions can be added, thus the rate of dissolving is equal to that of precipitaion
Equilibrium constant
Kc = [products] / [reactants]
- constant for a reaction at a specific temperature
Le Chateliers Principle
When a system at equilibrium is subjected to a change, the system will respond in such a way as to minimize the effect of the change. It will negate the change (negative feedback loop).
What are the 4 changes to consider with Le Chateliers Principle
- Changes in concentration of a reactant or product
- Changes in pressure
- Changes in temperature
- Addition of a catalyst
Changes in concentration (Le Chateliers)
- An increase or decrease in concentration will cause the reaction to shift to the opposite side
- A new equilibrium is established with the same value of Kc and rates forward and backward will still be =
Changes in pressure (Le Chateliers)
- Only for gas
- Reacll PV = nRT, if P increases and nRT are constant volume decreases
- Increase in P : shift to side with less gas moles
- Decrease in P: shift to side with more gas moles
- May increase rates equally
Changes in temperature (Le Chateliers)
- Kc will change
- If temp increases, endo is increased, exo decreased
- If temp is decreased, exo is increased, endo decreased
Addition of a catalyst (Le Chateliers)
- Increases rate by decreases Ea equally
- no effect on position of equilibrium or Kc
Temp change chart
Exo - increase T - left - K decrease
Exo - decrease T - right - K increase
Endo - increase T - right - K increase
Endo - decrease T - left - K decrease
