Chemical Equilibrium Flashcards
When is a chemical reaction at equilibrium?
When the composition of the reactants and products remains constant indefinitely, when the rate of the forward reaction = the reverse.
What does a chemical system in equilibrium show?
No changes in macroscopic properties, such as overall pressure, total volume and conc of reactants and products.
What is the equilibrium constant?
Kc = [C]^c[D]^d / [A]^a[B]^b
Note : it’s temperature dependant
What is Kp?
The equilibrium constant for reactions involving gaseous reactants and products (expressed in terms of partial pressures)
Kp = (PC^c ✖️ PD^d ) ➗ (PA^a ✖️PB^b)
What are homogeneous reactions?
When all the reactants and products have been in the same phase (I.e. All in liquid/solution or all gaseous)
What are heterogeneous reactions?
When is has reactants and/or products in more than one phase
What factors will alter the composition of an equilibrium mixture?
1) addition of reactants/products
2) alteration of pressure
3) change in temperature
4) the influence of catalysts
What is Le Chatelier’s principle?
When a change is applied to a reaction mixture at equilibrium, reaction will occur in a direction that will reduce the change
What happens to the equilibrium constant for ectothermic and endothermic reactions ?
Exothermic - K decreases with increasing temp
Endothermic - K increases with temp
