Equillibrium Flashcards
What is the equilibrium?
When the rate of the forward reaction is equal to the rate of backwards reaction, the system reaches dynamic equilibrium.
Can equilibrium be reached in an open system?
No, the system should be closed, where no gaseous products can escape container.
What type of reaction would occur on an open system?
An irreversable reaction.
What is the difference between rate and extent?
Rate refers to how quickly reaction proceeds, while extent refers to degrees of conversion.`
What 2 factors do manufactures consider when establishing reactions?
Rate and yield.
What does competing equillibira refer to and what it one example?
When reactions occur simultaneously and the outcome of one reaction influences the other.
Eg. oxygen and co competing equilibria
Why would small amounts of CO be harmful for someone when there is plenty of O2 around?
CO has an extremely high Kc and so its reaction is favoured in comparison to oxygens. CO will be more strongly absorbed by haemoglobin, preventing O2 from binding with HB.
Does temperature effect Kc?
YES
What is Kc a measure of?
The yield or extent of reaction.
What does a low Kc mean and what does a high Kc mean?
Low: reverse reaction is favoured- more reactants
High: forwards reaction is favoured- more products
What is the concentration quotient?
Q is a form of the equilibrium expression which is a measure of the relative amounts of products and reactants present. It indicates weather reaction is at equilibrium or not.
What does a low Q mean and what does a high Q mean?
Low: reverse reaction is favoured- more reactants
High: forwards reaction is favoured- more products
What is the Q and Kc expression used to identify extent of reaction?
Kc < Q < Kc
What is the reactionship between Kc and n, where n is the value that the equation is changed by?
(kc) ^n
What tool should you always use when calculating equillibrium concebtrations?
Rice table.
What is Le Chatliers principle?
When a system in =m, is subjected to change equilibrium will shift in order to favour the reaction that partially oposes the change.
How does adding product effect equilibrium?
same as removing reactant
System favours net backwards reaction.
How does adding reactant effect equilibrium?
same as removing product
System favours net forwards reaction.
How does diluting reaction effect equillibrium?
System favours reaction with most moles in order to increase concentration.
How does increasing pressure effect equillibrium?
same as decreasing volume
System favours reaction with least moles in order to reduce volume.
How does decreasing pressure effect equillibrium?
same as increasing volume
System favours reaction with most moles in order to
increase volume.
How does increasing temp effect equillibrium of exothermic reaction?
System favours net backwards reaction in order to decrease temp.
Kc descreases
How does decreasing temp effect equillibrium of exothermic reaction?
System favours net fowards reaction in order to increase temp.
Kc increases
How does increasing temp effect equillibrium of endothermic reaction?
System favours net fowards reaction in order to increase temp.
Kc increases
How does decreasing temp effect equilibrium of endothermic reaction?
System favours net backwards reaction in order to decrease temp.
Kc descreases
How does adding an inert gas to a solution affect the equilibrium?
It increases the volume, hence pressure decreases. This means the equilibrium will shift to the side with the most amount of moles.
How do you answer equilibrium questions?
- describe the change
- describe Le Chateliers principle
- describe the equilibrium
Answer the following question:
When more reactant is added, what colour will the solution be?
left= clear right= brown
When [O2] increases, the system will adjust to partially oppose the change and favour the reaction that decreases [O2]. Therefore the equilibrium shifts in a net forwards direction, producing more NO2 which increases browness.
