Reversible reactions Flashcards
A + B ⇌ C + D
- What do this show? part 1
- reversible reaction
- As reactant reacts , their concentration fall = forward reaction slow down.
- But as more products are made and their concentration rises, the backward reaction will speed up
- After a while, both forward reaction and backward one are at exactly same rate = system is at equilibrium
A + B ⇌ C + D
- What do this show? part 2
- At equilibrium both reactions are still happening, but, there’s no overall effect.
- This means concentrations of reactants and products reach a balance and won’t change
- Equilibrium only takes place if reversible reaction takes place in closed system
-( Define closed system )
When a reactions at equilibrium, are both amounts of reactants and products the same ?
- No
- If equilibrium lies to the right, concentration of products is greater than that of the reactions
- VICE VERSA
What does the position of equilibrium depend on?
- The following conditions
⭐ temperature
⭐ pressure
⭐ concentration of reactants and products
e.g. Ammonium chloride ⇌ ammonia + hydrogen chloride
Effect of temperature
Heating this reaction moved equilibrium to the right and cooling it moves it to the left.
Reversible reactions can be —– and ———-
endothermic, exothermic
What happens if your reaction is endothermic in one direction?
- It will be exothermic in the other
The energy transferred from the surrounding by the endothermic reaction is equal to the energy transferred to the surrounding during exothermic reaction
Thermal decomposition of hydrated copper sulphate
hydrated copper sulphate (endothermic -> )( exothermic <-) ⇌( exothermic <-) (endothermic -> ) anhydrous copper sulphate + water
-If you heat blue hydrated copper (II) sulphate, it drives water off and leaves white anhydrous copper (II) sulphate powder. = endothermic
If you add couple drops of water to white powder, you get the blue crystals back = exothermic
