Equilibria Flashcards
What is dynamic equilibrium?
Its when the rate of the forward and reverse reactions are equal.
What is a closed system?
When the reaction is carried out in a sealed container, so no reactants or products are lost.
What are the concentrations of reactants and products at equilibrium?
They are constant but not necessarily (in fact rarely) equal.
Why do chemists move the position of equilibrium?
To favour the products and maximise their profits.
What is an example of a reaction where chemists change the position of equilibrium?
The Haber Process, this uses high pressure to favour products and a medium temperature. The forward reaction is exothermic so favours low temps, but too low would cause the rate to be slower and therefore not as profitable.
How does changing temperature affect the equilibrium?
Increasing the temperature favours the endothermic reaction, it shifts in the endothermic direction.
Decreasing temperature favours the exothermic reaction, it shifts in the direction of the exothermic reaction.
How does changing pressure affect the equilibrium?
- Changing pressure only affects GASEOUS molecules.
- Increasing the pressure favours the side with lower gas volume.
- Decreasing the pressure favours the side with higher gas volume.
How does adding/removing the reactants/products change the equilibrium?
- adding any chemical that is a product/reactant or can react with one of them can alter the equilibrium.
- Adding a reactant will shift the equilibrium to the right.
- Adding product - shift the equilibrium to the left.
- Neutralisation reactants can affect equilibrium if the equation contains hydrogen ions (H +) or hydroxide ions (OH - ).
- Adding NaOH will add hydroxide ions which can react with the H+ to form water.
What is the effect of catalysts on equilibrium?
- Catalysts have no effect on equilibrium position.
- They allow the equilibrium to be reached quicker and at a lower temperature.
