Equilibrium Constant - Equilibria Pt A - (4.2)

Question 1

What is the equilibrium constant?

Answer 1

A constant that describes the ratio of products & reactants in a given equilibrium at a given temperature

Question 2

How is the equilibrium constant represented in an equation?

Answer 2

Kc

Question 3

Give the general equation for finding Kc

Answer 3

Kc = concentration of products/concentration of reactants

-Add exponents from reaction stoichiometry (e.g in the equation if reactant is 2R in the equation it would be [R]^2)
- Multiply the concentration of reactants together (do same for products) e.g if A+2B -> C,
Kc = [C]/[A][B]^2

Question 4

What does it mean if Kc is large (>1)?

Answer 4

• The concentration of products is larger than that of the reactants
• The equilibrium lies to the right

Question 5

What does it mean if Kc is small (<1)?

Answer 5

• The concentration of the reactants is larger than that of products
• The equilibrium lies on the left

Question 6

What factors do affect the value of Kc?

Answer 6

Only change in temperature - the effect of changing the temperature is that the concentration of one side increases & the other decreases

Question 7

What factors do not affect the value of Kc?

Answer 7

• Changing concentration
• Changing pressure
  (For both these factors the equilibrium will shift to restore the ratio of Kc)
• Catalyst
  (does not effect the equilibrium so does not affect Kc)