Unit 1.1 Equilibrium Flashcards
Unit 2: Physical Chemistry
What is meant by an Open System?
Matter and energy can move between the system and the surrondings
What is meant by an Closed System?
Matter cannot move between the system and surroundings, but energy can
What is meant by an Isolated System?
Neither matter nor energy can move between the system and the surroundings
What is an equilibrium?
The point at which the forward reaction and reverse reactions reach the same rate
What happens to the concentrations of reactants and products at equilibrum?
The concentrations of the reactants and products in the system remain constant indefinitely
What does Le Chatelier’s Principle state?
If a dynamic equilibrium is disturbed by a change in the conditions, the position if equilibrium shifts to counteract the change
What happens when there is an increase in reactant concentrations?
-Equilibrium adjusts to counteract the charge - to bring the conc down
-More reactants react, so forward reaction is favored
-Equilibrium shifts right
-Useful way to increase product yield
What happens if there is a decrease in reactants concentration?
-Equilibrium shifts to counteract the change - to bring reactants back up
-Reverse reaction forward
-Equilibrium shifts left
What happens when there is an increase in products?
-Equilibrium shifts to counteract the change to bring down
-Reverse reaction favored more reactant produced
-Shifts left
What would happen if there is a decrease in products?
-Equilibrium shifts to counteract the change
-Bring products back up
-Forward reaction favored more product
-Equilibrium shifts right
When would pressure effect equilibrium?
-Reactions involving gases
-If the number of moles of reactant differs from the number of moles of product
What happens if there is an increase in temperature in an exothermic reaction?
-Equilibrium shifts to bring it down so shifts left increasing conc of reactants and decreasing conc of products
-The system must absorb the additional energy so the endothermic reaction is favoured
What happens if there is a decrease in tempeture in an exothermic reaction?
-Equilibrium shifts to raise the tempeture (release energy)
-Exothermic reaction is favoured
-Equilibrium shifts right favouring the favourite reaction
Does a catalyst effect the position of an equilibrium?
No
What impact does a catalyst have on equilbrium?
A catalyst decreases the time taken to reach equilibrium but does not affect the composition of the equilibrium mixture, so has no effect on K
What are the 2 types of equilibrium?
Homogenous and Heterogeneous
What is homogenous equilibrium?
All substances are present in the same phase/state
What is heterogenous equilibrium?
Substances are present in more than one phase
What is K dependant on?
Tempeture
What is K’s units?
K does not have units
What is K unaffected by?
Concentration of reactants, change in pressure or presence of a catalyst at a stated tempeture
What does equimolar mixture mean?
Same concentration
What does a high K value suggest about the composition of an equilibrium mixture?
Mostly product, equilibrium lies to the right, forward reaction favoured
What does a low K value suggest about the composition of an equilibrium mixture?
Mostly reactants, equilibrium lies to the left, reverse reaction favoured
What value is given to H2O
1
What does RICE stand for?
Ratio
Initial
Change
Equilibrium
