Equilibria Flashcards
Give the definition of Dynamic Equilibrium
A reaction where there’s no overall change in the concentrations of products + reactants . Rates of forward and backwards are equal, and will only occur in a closed system
What is Le Chateliers Principale
A system at equilibrium will react to oppose any change imposed upon it
what effect does a catalyst have on the position of equilibrium
It will have no effect on the position of equilibrium and increases rate of forward and backwards reaction equally
what happens when you increase temperature (equilibrium)
Favours endothermic direction
What happens when you increase pressure (equilibrium)
Favours side with least amount of moles
Explain the compromise of temperature and following le chateliers principle when making ethanol
Temperature - increasing will lead to lower yield as froward is exo. lower means a very slow rate of reaction
Pressure - A high pressure will increase yield but the environments needed are expensive
What is the Kc Expression
If equation is 2A + B –> 2C + D
If equation is 2A + B –> 2C + D
[A]2 [B]
What happens when more units at the bottom? (Kc)
Invert units
What affects Kc
Temperature
if equilibrium shifted right, Kc increases (vice versa)
What is a closed system?
No reactants/products can escape
What happens to the position of equilibrium if pressure is changed but both sides of the equation have an equal number of moles?
Changes in pressure will have no effect on equilibrium position
What does a positive delta H suggest?
Reaction is endothermic
What does a negative delta H suggest?
Reaction is exothermic
What temperature conditions are used during the haber process and how do they compare with the ideal conditions?
N2 + 3H2 –> 2NH3 (EXOTHERMIC)
A low temp would be ideal because the forward reaction is exothermic and a low temperature will favour the exothermic reaction and increase the ammonia yield. However, this cannot be achieved in industry because low temperature decrease the rate of the reaction. A compromise temperature Is used to balance rate and yield
What pressure conditions are used during the haber process and how do they compare with the ideal conditions?
A very high pressure would be ideal because that will favour the side with the fewest moles of gas (products) and increase the yield of ammonia and the rate at which it is produced. However, high pressures can be very expensive and dangerous so a compromise pressure is used to balance yield and rate with safety and cost
