19.3 Controlling The Position Of Equilibrium Flashcards
Le Chatelier’s principle concepts
If concentration of species is increased, equilibrium shifts in direction to reduce concentration
If pressure is increased, the equilibrium shifts towards the side with fewer gas molecules
If temperature is increased, equilibrium position shifts in endothermic direction
What does an equilibrium constant K=1 indicate
Equilibrium halfway between reactants and products
What does an equilibrium constant K>1 indicate
Equilibrium in favour of the products
What does an equilibrium constant K<1 indicate
Equilibrium well in favour of the reactants
What changes the value of K
TEMPERATURE ONLY
What happens to K when there is an exothermic forward reaction
Equilibrium constant decreases with increasing temperature
Raising temperature decreases the equilibrium yield of products
Kp decreases with increasing temperature
Equilibrium position shifts to left
Explaining equilibrium shift when the forward reaction is exothermic
If temp increases
Kp decreases
System is no longer in equilibrium
Ratio of reactants and products > Kp
Equilibrium partial pressures giving Kp at original temperature must change to give the new Kp value at the increased temperature
Partial pressure of numerator must decrease
Partial pressure of denominator must increase
Position of equilibrium shifts toward reactants
New equilibrium reached where fraction is equal to new Kp value
If the forward reaction is endothermic
Equilibrium constant increases with increasing temperature
Raising temperature increases equilibrium yield of products
Kp increases with increasing temperature
Equilibrium position shifts to right
Explaining equilibrium in endothermic reactions
If temperature increases
Kp increases
System no longer in equilibrium
Ratio of partial pressures < Kp
Partial pressure of numerator must increase
Partial pressure of denominator must decrease
Position of equilibrium shifts toward products
New equilibrium established where fraction is equal to the new Kp value
What happens with equilibrium shifts for Kc
When supplied with Kc info, you can also apply it to the same idea as Kp
Equilibrium constants and concentration changes
If reactants concentration increased
Ratio < Kc
System no longer in equilibrium
Concentrations must change to return ratio back to Kc
Concentration of numerator must increase
Concentration of denominator must decrease
New equilibrium established where fraction is equal to its Kc value
Equilibrium constants and pressure changes
Doubling pressure results in doubling of partial pressures and concentration of reactants AND products
Ratio now > Kp
System no longer in equilibrium
Partial pressures must change to return ratio back to Kp
Ratio when fewer molecules of gaseous products
Ratio < K
Effect of increasing pressure on fewer moles of gaseous products
Products increase, reactants decrease
Equilibrium shifts right
Ratio of more moles of gaseous products
Ratio > K
