Kc and Kp Flashcards
What is Kc in terms of?
Equilibrium concentrations
What is Kc dependant on?
Temperature
What is Kc?
A constant
What does a value of 1 for Kc tell you?
Position of equilibrium is halfway between reactants and products
What does a value of >1 for Kc tell you?
Position of equilibrium is towards the products
What does a value of <1 for Kc tell you?
Position of equilibrium is towards the reactants
What does the larger the value of Kc mean?
The further the position lies to the right so the greater the concentration of products compared to the reactants
What does the square brackets of Kc and Kp mean?
“Concentration of”
What does a,b,c,d of Kc and Kp mean?
Balancing numbers in the equation
What does A,B,C,D of Kc and Kp mean?
Equilibrium concentrations
What is different between Kc and Kp?
Kp is for gaseous equilibrium
What does the p mean in Kp?
Partial pressure
What is Kp dependent on?
Temperature
What is the equation for partial pressure?
Mole fraction X total pressure
What must the mole fraction add up to?
1
What must the partial pressure add up to?
The total pressure
What type of calculation must you use when calculating Kp?
ICE calculations
Describe an ice calculation
Initial moles - products always have 0 initial moles
Change
Equilibrium moles
Equilibrium concentration
When will K only change?
When you change temp
If you change pressure, conc or use a catalyst K will only change if temp also changes
What happens to K when temp increases (exo)?
K decreases
Equilibrium shifts to the left
What happens to K when temp decreases (endo)?
K increases
Equilibrium shifts to the right
Why does Le Chatelier’s Principle only work?
As K controls the relative conc of reactants + products at equilibrium to maintain a constant value
What happens if you increase the pressure?
Increase of pressure shifts to side with fewest molecules of gas
So to return Kp back must increase reactant + decrease product
So equilibrium shifts left
What happens if you increase pressure on ammonia production?
Conc of everything increases
So value of Kc decreases as conc increases
To restore Kc must increase reactants + decrease products
How do you restore Kp if you increase the temp?
Must decrease the reactants + increase the products
Are equilibrium constants affected by catalysts?
NO
What do catalysts do?
Affect rate of reaction but not equilibrium position
