Eqillibria + Redox Flashcards
What are 2 features of a dynamic equilibrium
The forward and backwards reactions occur at the equal rates
The concentrations of reactants and products stay constant
What does dynamic mean
The forward and backward reactions are occurring simultaneously
How does increasing temperature affect equilibrium
Equilibrium shifts to oppose this
So moves in endothermic direction
To try and reduce temperature by absorbing heat
What happens if temperature is decreased
Equilibrium shifts to oppose change
Moves in exothermic direction
To try increase temperature by giving out heat
What happens if you increase pressure
Shift to oppose change
Shifts to side with fewer more
To try reduce pressure
What happens if you increase pressure
Shifts to oppose change
Shifts to side with less moles of gas
To decrease pressure
What effect does changing pressure have if moles of gas are the same on both sides
No effect
Why is pressure compromised
High pressures are expensive to maintain due to expensive equipment and high electrical costs for pumping gases to make high pressure
Why is temperature compromised
Low temp can slow rate
But can give higher yield sometimes
How does changing concentration affect equilibrium
It shifts to oppose change
So moves to the side you’ve increased or decreased
How does a catalyst affect equilibrium
A catalyst has no effect on position of equilibrium but will speed up the rate at which the equilibrium is achieved (both forward and backwards reactions)
Why does a catalyst not affect the position of equillibrium
It speeds up the rate of forwards and backwards reaction by the same amount
What is the equation for haber process
N2 + 3H2 =(rvs) 2NH3
What is the equation for the production of methanol from CO
CO + 2H2 =(rvs) CH3OH
What is the equation for the hydration of ethene to produce ethanol
Ethene + H20 =(rvs) CH3CH2OH
What is carbon neutral
An activity that has no net annual carbon emissions to the atmosphere
How can the overall yield of reversible processes be improved
Recycling unreacted reactants
What is Kc
The equillibrium constant
How to calcite the value of Kc
Use RICE and then put into Kc expression
How does the size of Kc relate to products and reactants
The larger the Kc then the greater the amount of products
If Kc is small then the equillibrium favours the reactants
Which is the only variable that affects Kc
Temperature
What is oxidation
Loss of electrons
What is reduction
Gaining electrons
What is an oxidising agent
A species that causes another element to oxidise (it is reduced itself )
What is a reducing agent
A species that causes another element to reduce (it is oxidised itself)
What side are electrons on in half equations for reduction and oxidation
Reduction - left
Oxidation - right
What is partial pressure
The pressure that the gas would have if it occupied the volume occupied by the whole mixture alone
What is the calculation for partial pressure
Mole fraction x total pressure of gas
What is the mole fraction
Number of moles of gas / total number of moles of all gases
How do you write a Kp expression
Products over reactants
Brackets not square brackets
Small p to signify partial pressure
What do Kp expression contains only
Gaseous substances, anything else if left out
How does the size of Kp relate to reactants and products
The larger the Kp then the more products we have, if Kp is small then the equillibrium favours the reactants
What is the only variable that affects Kp
Temperature
Why is Kp not affected by pressure changing
If you increase pressure the Kp on bottom increases more than the top
Equillibrium shifts to the right which increases mole fraction for product b it not reactants
So top of Kp expression also increases and bottom decreased so original Kp is restored
