Equillibrium Flashcards
What is dynamic equilibrium?
The equillibrium that exists in a closed system when the forwrd rate is equal to the reverse rate of reaction.
What are the conditions of a dynamic equilibrium?
Closed system
The concentration of the reactants and products remain the same.
The rate of the forward reaction is equal to the rate of the reverse reaction.
Whats Le Chateliers Principle?
When a system in equilibrium is subject to an external change, the position of equilibrium moves in a way to minimise the change.
What happens position of equilibrium when concentration of reactants increases?
Moves right to minimise the increase in conc of reactants so more products are made.
What happens to position if pressure increases or decreases? (Only in Gases)
Increases: moves to side with least number of moles of gas
Decreases: moves to side with highest number of moles.
(If increase/decrease pressure of individual component it has the same affect as concentration does)
What does increasing/ decreasing the temp have on position of equilibrium?
Increase: moves in endothermic direction to minimise the increase in temp to take in more energy.
Decrease: moves in the exothermic direction to minimise the decrease in temp to give out more energy.
What affect does a catalyst have on position of equilibrium?
No affect as increases both forward and reverse rate by same. However, it will reach it faster.
What colour change would you observe if conc of H2 increased/decreased and what would it be at dynamic equilibrium if reaction is - N2 +3H2 ( pink ) —> 2NH3 (blue)
Increases: move right so become more blue.
Decreases: moves left so become more pink
Dynamic equilibrium: in between pink and blue.
What look for when investigating equilibrium position?
Colour change due to change in concentration or temperature.
Whats the theoretical and actual conditions used for haber process?
Temperature: theoretical = low temp. actual = 400-500’C high enough to achieve a fast rate of reaction and produce an acceptable yield.
Pressure: theoretical = high (dangerous and costly). Actual= 200atm prosuces a high rate and yield but isnt too dangerous or expensive.
Iron catalyst: equilibrium achieved faster so lower temperatures used reducing energy demand and reduces fossil fuels/CO2 emissions.
What can you calculate to show the position of equilibrium?
Equilibrium constant Kc
(The equilibrium law defines the Kc in terms of concentrations
Whats the significance of the Kc?
- Kc of 1 indicates position equilibrium halfway between reactants and products.
- Kc >1 indicates position of equilibrium that is more towards products
- Kc <1 indicates position of equilibrium that is more towards reactants
