Unit 3- Equilibrium Flashcards
What can be changed in a reaction to alter the equilibrium position?
Concentration, temperature, pressure/volume (only applies to gases)
What happens to the equilibrium position when the product concentration is increased?
The reverse reaction increases and equilibrium moves to the left
What does Le Châtelier’s principle state?
If an equilibrium system is subjected to a change, the system will adjust itself to partially oppose the effect of the change
What happens to the equilibrium position when the reactant concentration is increased?
The forward reaction increases and equilibrium moves to the right
On an equilibrium graph, how do you know the reaction has reached equilibrium?
When equilibrium is established the concentration lines are horizontal
What is meant by an “open system”?
An open system allows matter and energy to be exchanged with the surroundings
Are all reactions reversible?
No, for example due to the formation of energetically stable products or loss of products into the environment
What is a “closed system”?
A reaction vessel that does not allow the reactant or product particles to escape
Give an example of an “open” system.
A flask with no lid that allows heat and gas products to escape
What type of system is it when energy can escape but not matter?
Closed system
What is meant by the term “reversible reaction”?
Reactions in which the conversion of reactants to products and products to reactants occur simultaneously.
Are physical changes reversible?
Generally, they are reversible as chemical bonds remain unchanged
Why is a substance in a system more likely to react when the temperature is higher?
The particles of that substance have more kinetic energy, causing them to collide more often with the other particles in the system, making the reaction occur
How are equilibrium reactions symbolised?
Equilibrium reactions are symbolised by ⇌
What is activation energy?
The minimum amount of energy required in the collision between reactants for a reaction to occur
What can you measure using observation in equilibrium reactions?
You can observe whether the forward or reverse reaction has occurred if the reactants and products have different colours
In a reaction where gas is produced what type of system is required for equilibrium to be reached?
A closed system
What does Kc represent?
The equilibrium constant
When is a state of dynamic equilibrium reached?
A state of equilibrium is reached when the rate of the forward and reverse reactions are equal
How can you measure the concentration of equilibrium using pH?
You can measure the change in pH and calculate the H3O+ concentration, then use simple stoichiometry
Can forward and reverse reactions occur at the same time?
Yes, a forward and reverse reaction can occur at the same time if the reaction occurs within a closed system
What is the impact on the equilibrium position when a catalyst is added to a reaction in a closed system?
There is no impact on the equilibrium position. Equilibrium will only be reached faster
What concentrations are not included when calculating the equilibrium constant?
Concentrations of pure liquids and solids are not included, water is only included if it is a product such as in condensation reactions
Where can the elements with the lowest ionisation energy be found on the periodic table?
“Bottom left e.g. Cs, Rb, Ba”
