Equilibria Flashcards
What is a reversible reaction?
A reaction that can go forwards or backwards depending on the conditions.
What is an equilibrium reaction?
A reaction which does not go to completion and the reactants and products are present in fixed concentration ratios.
What is dynamic equilibrium?
When the rate of the forward reaction and the rate of the backward reaction are the same in a closed system and the concentration of the products and the reactants remains constant. It is constantly occurring.
What is a closed system?
One in which neither the reactants nor the products can escape from the reaction mixture.
What are the four characteristics of equilibrium?
- It is dynamic
- It requires a closed system
- The rate of the forward and backward reactions are the same
- The concentrations of the reactants and products are the same
How can we get to an equilibrium state?
We can either start with just the reactants or just the products.
Can a chemical reaction reach equilibrium in an open system?
Yes, as long as the reaction does not lose any gas.
If the concentrations of both reactants and products are constant, does that mean they are equal?
No
What is the position of equilibrium?
The relative amounts of reactants and products in an equilibrium mixture.
To where does the position of equilibrium shift when there is a higher concentration of products than reactants?
To the right (products)
To where does the position of equilibrium shift when there is a lower concentration of reactants than products?
To the left (reactants)
What does Le Chatelier’s principle state?
If one or more factors that affect dynamic equilibrium are changed, the position of equilibrium will shift to minimise this change.
What effect will an increase in pressure have on the position of equilibrium?
The position of equilibrium will shift towards the side with the fewest gaseous molecules in order to decrease the pressure.
What effect will a decrease in pressure have on the position of equilibrium?
The position of equilibrium will shift towards the side with the larger number of gaseous molecules to increase pressure again.
If there is an equal number of gaseous molecules on both sides, what effect will a change in pressure have?
There will be no effect
For an exothermic reaction, what is the effect of increasing temperature?
Equilibrium shifts to the left (reactants)
For an exothermic reaction, what is the effect of decreasing temperature?
Equilibrium shifts to the right (products)
For an endothermic reaction, what is the effect of increasing temperature?
Equilibrium shifts to the right (products)
For an endothermic reaction, what is the effect of decreasing temperature?
Equilibrium shifts to the left (reactants)
What effect does a catalyst have on the position of equilibrium?
None. It just increases the rate at which the forward and backward reactions take place.
Why are high pressures expensive to produce?
- High electrical energy costs for pumping
- Equipment is expensive
What is manufactured in the Haber Process?
Ammonia
What are the conditions needed when carrying out the Haber Process?
- Temperature of 450 degrees
- Pressure of 200-1000atm
- Catalyst Iron
What is the advantage of using catalysts in the Haber and Contact Processes?
A lower temperature can be used to reduce energy costs as the catalyst speeds up the rate, allowing for this temperature compromise.
What is needed to carry out the Contact Process?
- Temperature of 450 degrees
- Pressure of 1 or 2atm
- Catalyst Vanadium (V) Oxide
