equilibrium / reversible reactions Flashcards
What is a reversible reaction?
a reversible reaction is a reaction where the products can react to reform the original reactants
What happens to the energy in reversible reactions?
if a reversible reaction is exothermic in one direction, it is endothermic in the opposite directions
so when the forward/reverse exothermic reaction takes place, energy is released and the temperature of the system increases
and when the reverse/forward endothermic reaction takes place, energy is taken in and the temperature of the system decreases
What is equilibrium?
this is when the forward and reverse reactions will take place at exactly the same rate
LE CHATELIER’S PRINCIPLE
what happens to equilibrium if we change the conditions
if a system is at equilibrium and a change is made to the conditions, then the system (a reaction) responds to counteract the change
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What happens if we change the concentration of the reactants or products in a reaction when its at equilibrium?
the concentration of all the substances will change until equilibrium is reached
what happens when there is a decrease and an increase in concentration during a reversible reaction at equilibrium?
if there is a decrease in the concentration of a substance in a reaction then the reaction is no longer at equilibrium then more of the other substance will react to bring the reaction back to equilibrium
if there is an increase in the concentration of a product in a reaction then the reaction is no longer at equilibrium so more of the product will have to be un-reacted to form more of the reactant so the reaction is one again at equilibrium
what happens when we increase the temperature of a system at equilibrium when the forward reaction is exothermic and the reverse reaction is endothermic?
if we increase the temperature of the system then the equilibrium shifts to the left to reduce the temperature because the reverse reaction is endothermic so energy is take in causing the temperature to fall
but if we decreased the temperature the equilibrium shifts to the right to increase the temperature this is because the forward reaction is exothermic so energy is released causing the temperature to increase
What type of reactions does pressure affect and what does it depend on?
pressure affects reactions involving gases
the pressure of gas depends on the number of molecules eg. if there is two containers each containing gas and one of them had twice as many molecules as the other one the that would mean it also has twice the pressure
What happens to a reversible reaction at equilibrium when the pressure is changed?
if we increase the pressure on a reversible reaction at equilibrium, the position of the equilibrium shifts to the side with the smaller number of molecules
but if we reduce the pressure, then the position of the equilibrium shifts to the side with the larger number of molecules
how do we find the amount of molecules in in a substance
the big numbers infront of the letters e.g 2H = 2 N = 1
