Topic 19 - Dynamic Equilibrium Flashcards
Describe the decomposition of ammonium chloride
NH4Cl (s) —> NH3 (g) + HCl (g)
Describe the dehydration of copper sulphate crystals
(heat)
CuSO4•5H2O (s) —> CuSO4 (s) + 5H2O (l)
What is dynamic equilibrium?
When the concentrations of reactants and products will reach a certain balance and stay there.
The reactions are still taking place in both directions, but the overall effect is nil because the forward and backward reactions cancel each other out - they are taking place at exactly the same rate.
What is needed for dynamic equilibrium to be achieved?
A closed system, so none of the reactants or products can escape.
What are the 3 factors which affect the position of the equilibrium?
Temperature, pressure (of gas!!) and reactants & products
What is the guiding principal?
Position of equilibrium shifts to counteract change
What happens when you add some more reactant/product?
The position would shift in whichever direction used up the added substance
What happens when you take away some of the reactant/product?
The equilibrium will shift in whichever direction creates more of the substance removed
What happens when you increased the gas pressure?
The equilibrium shifts to reduce the pressure-> it shifts in whichever direction converts more moles of substance into less moles of substance
What happens if you decrease the gas pressure?
The equilibrium shifts to increase the pressure -> it shifts in whichever direction converts less moles of gas into more moles of gas
What happens if you increase the temperature?
The equilibrium shifts to decrease the temperature.
You will be given ΔH, and ΔH always shows the forwards reaction.
So, it shifts in whichever direction causes an endothermic reaction
What happens in you decrease the temperature?
The equilibrium shifts to increase the temperature.
You will be given ΔH, and ΔH always shows the forwards reaction.
So, it shifts in whichever direction causes an exothermic reaction
What happens when you use a catalyst in a reversible reaction
Nothing, because it speeds up the forwards and backwards reaction by the same amount
