Embedded Files
K or Kc is the equilibrium constant.
K or Kc is the equilibrium constant.
CHemical equilibrium
CHemical equilibrium
Chemical equilibrium is the state in which both reactants and products are present in concentrations which have no further tendency to change with time. Usually, this state results when the forward reaction proceeds at the same rate as the reverse reaction.
Chemical equilibrium is the state in which both reactants and products are present in concentrations which have no further tendency to change with time. Usually, this state results when the forward reaction proceeds at the same rate as the reverse reaction.
key points
key points
Not all reactions are one way, some are reversible.
Not all reactions are one way, some are reversible.
In this case the symbol to the side is used.
In this case the symbol to the side is used.
An example of a reversible reaction is that between Nitrogen and Hydrogen.
An example of a reversible reaction is that between Nitrogen and Hydrogen.
Reversible reactions have an equilibrium point at which the rate of the forward reaction (reactants into products) is the same as the rate of the reverse reaction (products into reactants)
Reversible reactions have an equilibrium point at which the rate of the forward reaction (reactants into products) is the same as the rate of the reverse reaction (products into reactants)
THIS DOES NOT MEAN THE AMOUNT OF REACTANTS AND PRODUCTS ARE EQUAL - JUST THE RATES OF REACTIONS.
THIS DOES NOT MEAN THE AMOUNT OF REACTANTS AND PRODUCTS ARE EQUAL - JUST THE RATES OF REACTIONS.
For equilibrium reactions to take place the system must be closed, and as they are constantly moving we called it dynamic equilibrium
For equilibrium reactions to take place the system must be closed, and as they are constantly moving we called it dynamic equilibrium
le chatelier's principle
le chatelier's principle
This principle helps us to understand equilibrium and how chemical systems at equilibrium respond to external changes / stimuli
This basically says that if any change is made to a system at equilibrium then the system will change / shift to minimise / correct that change.
This basically says that if any change is made to a system at equilibrium then the system will change / shift to minimise / correct that change.
At this stage (Level 2) there are only 4 things that can affect equilibirum:
At this stage (Level 2) there are only 4 things that can affect equilibirum:
Concentration
Concentration
Pressure
Pressure
Temperature
Temperature
Catalsyt
Catalsyt
In simple terms:
In simple terms:
If we increase the concentration the system will move to reduce the concentration.
If we increase the concentration the system will move to reduce the concentration.
If we increase the pressure the system will move to reduce the pressure.
If we increase the pressure the system will move to reduce the pressure.
If we increase the temperature the system will move to decrease the temperature. This depends on whether the forward reaction is exothermic or endothermic. If the forward reaction is exothermic and the temperature is increased, the system at equilibrium will shift in favour of the reverse reaction to use up this increased heat; it will favour the endothermic reaction.
If we increase the temperature the system will move to decrease the temperature. This depends on whether the forward reaction is exothermic or endothermic. If the forward reaction is exothermic and the temperature is increased, the system at equilibrium will shift in favour of the reverse reaction to use up this increased heat; it will favour the endothermic reaction.
Adding a catalyst does not change equilibrium - it only speeds up rates of reactions ( in both directions) meaning equilibrium will be reached more quickly.
Adding a catalyst does not change equilibrium - it only speeds up rates of reactions ( in both directions) meaning equilibrium will be reached more quickly.
The video below shows some examples of equilibrium processes in chemical systems
The video below shows some examples of equilibrium processes in chemical systems
industrial equilibrium
industrial equilibrium
At Level 2 you need to have an idea of the following imdustrial equiibria:
At Level 2 you need to have an idea of the following imdustrial equiibria:
- The Haber process
- The Contact process
In industry competing factors such as rate of reaction, amount of yield, as well as cost need to be considered, so a compromise between these competing factors is reached.
In industry competing factors such as rate of reaction, amount of yield, as well as cost need to be considered, so a compromise between these competing factors is reached.
the haber process
the haber process
The Haber process, also called the Haber–Bosch process, is an artificial nitrogen fixation process.
The Haber process, also called the Haber–Bosch process, is an artificial nitrogen fixation process.
It is the the main industrial procedure for the production of ammonia today.
It is the the main industrial procedure for the production of ammonia today.
It was invented by the German chemists, Fritz Haber and Carl Bosch, in the first half of the 20th century.
It was invented by the German chemists, Fritz Haber and Carl Bosch, in the first half of the 20th century.
There is a compromise between the temperature used and pressure of the containment vessels
There is a compromise between the temperature used and pressure of the containment vessels
The Haber process
The Haber process
the contact process
the contact process
The Contact process is the industrial process used for large scale production of sulfuric acid, H2SO4 .
The Contact process is the industrial process used for large scale production of sulfuric acid, H2SO4 .
Like the Haber process compromise conditions are used to maximise the yield at the best rate of reaction, bearing in mind cost.
Like the Haber process compromise conditions are used to maximise the yield at the best rate of reaction, bearing in mind cost.
The presentation below goes through the equilibrium principles and the compromise conditions used.
The presentation below goes through the equilibrium principles and the compromise conditions used.
Report abuse