Chemical Equilibrium + Stoicheometry Flashcards
What is the definition of Equilibrium?
An Equilibrium is a balanced state of constant change in a system. Chemical Equilibrium refers to the state in a reversable reaction when the rate of the forward is equal to the rate of the backwards reaction.
What is the Equilibrium Law?
This law states that for a reversible system, a constant that tells how for the reaction has gone to the right-hand side, by the time equilibrium has been established.
What is the formula associated with Equilibrium law?
A+BC+D, the equilibrium constant is given by: K=.
What is le chatelier’s principle?
This principle states that if a system in equilibrium is subjected to a stress, then the system will alter so as to oppose the effect of the stress.
What are the four types of stress?
- Concentration of reactants / products
- Temperature
- Pressure
- Catalysts
What happens if you change the conditions of a reaction at equilibrium?
The reaction readjusts itself to relieve the stress.
Which type of reactions does pressure only have an effect on?
Gaseous reactions
What prediction can be made of gaseous reactions in relation to Le Chatelier’s Principle?
An increase in pressure will favour the reaction which reduces the volume (ie towards the side with the smaller number of molecules).
What do Catalysts do in relation to chemical reactions?
Catalysts increase or decrease the rate of the forward and backward reaction by the same amount.
When an increase of pressure is applied, what is the systems response?
The equilibrium shifts to the side with a lower amount of molecules.
When an decrease of pressure is applied, what is the systems response?
The equilibrium shifts to the side with a higher number of molecules.
When an increase of temperature is applied, what is the systems response?
An endothermic reaction is favoured.
When an decrease of temperature is applied, what is the systems response?
An exothermic reaction is favoured.
When an increase of concentration of ‘x’ is applied, what is the systems response?
A reaction in which ‘x’ is removed is favoured.
When an decrease of concentration of ‘x’ is applied, what is the systems response?
A reaction in which ‘x’ is formed is favoured.
What type of catalyst does the Haber Process use?
It uses an Iron catalyst.
Is the Haber Process Exothermic or Endothermic?
It is exothermic in its forward reaction.
What is the chemical equation for the production of ammonia?
N2 + 3H2 <> 2NH3
Where is most ammonia made in Ireland?
It is mainly produced in the IFI Plant in Cobh, Cork.
Will increased or decreased pressure favour the production of ammonia (N2 + 3H2 <> 2NH3)? Explain why.
Increased pressure will favour the production of ammonia because of the four molecules on the left and the two molecules on the right.
Name one problem with keeping pressures high in the production of ammonia.
Keeping high pressures is expensive.
In the production of ammonia, what is the pressure that is kept? Why?
It is kept at 200 atmospheres because it is the most cost effective and safe.
Will increased or decreased temperature favour the production of ammonia?
Lowering temperatures will favour the production of ammonia but too low of temperatures can slow down production too much
What temperature does the producing of ammonia using Haber Process normally take place at?
500*C
In relation to the Haber Process, which types of temperatures and pressure are favoured?
The Haber Process favours high pressures and low temperatures.
Is the forward reaction of Contact Process exothermic or endothermic?
It is exothermic.
What is the equation for the formation of sulphuric acid?
2SO2 + O2 <> 2SO3
Does the process for forming sulphuric acid favour increased or decreased pressures? Explain why.
It favours increased pressure for production of 2SO3 because of the three molecules on the left and the two molecules on the right.
What is the pressure that is normally maintained during the Contact Process? Why.
Atmospheric pressure is normally maintained during this process because it is the most cost effective.
Will increasing or decreasing temperatures during the Contact Process favour the production of 2SO3?
Decreasing the temperatures will favour the production of 2SO3.
What temperature is normally maintained during the production of 2SO3?
450*C
What is Kc?
The equilibrium constant (Kc) indicates the extent to which the reaction has ‘gone to completion’.
What does a larger Kc value mean?
The larger the Kc value, the more that the reaction has gone to completion.
Turn “A + B <> C + D” into the equilibrium constant equation.
Kc = [C][D]/[A][B]
What is the emperical formula?
It is the formula of a compound that shows only the ratio in which the different types of atoms are present in the molecule.
What is a molecular formula?
The molecular formula of a compound indicates the number of atoms of each kind in the molecule.
What is the structural formula?
The formula of a compound showing the way in which the atoms are arranged in the molecule.
Name the 7 diatomic elements.
Hydrogen
- Nitrogen
- Fluorine
- Oxygen
- Iodine
- Chlorine
- Bromine
What is diffusion?
The spontaneous spreading out of a substance and is due to the natural movement of its properties.
How do you find the percentage yield?
(Actual yeild / theoretical yeild) x 100
