3.2.3: Chemical equillibrium Flashcards
What are features dynamic equillibrium ?
In a closed system where the rate of forward reaction = the rate of reverse reaction and concentrations of reactants and products don’t change
What type of equilibria does le chatelier’s principle apply to ?
Homogeneous equilibria
Do catalysts affect yield or equillibrium ?
NO - only affects rate of reaction - increases rate of forward and reverse reactions by the same amount
Give the equation for the Haber process
N2 (g) + 3H2 (g) reversible 2NH3 (g)
What are the compromised temperature conditions for the Haber process ?
450 degrees so low for a reasonable yield as forward reaction is exothermic but high enough so reaction isn’t too slow
What are the compromised pressure conditions for the Haber process ?
200 atm so high enough to give reasonable yield as forward reaction has fewest moles but low enough to reduce costs as no reinforced apparatus
How is a catalyst used in the Haber process ?
Iron catalyst speeds up the rate of the forward and backwards reaction by lowering Ea
What is taken out of the Haber cycle to benefit it ?
Ammonia is taken out meaning product concentration decreases so equillibrium shifts to the right to produce more ammonia
What happens to unreacted gasses in the Haber cycle ?
They are recycled
What is the equillibrium constant applied to ?
Homogeneous reactions
What does it mean if Kc is above 1 ?
Conc of products is greater than conc of reactants so equilibrium lies to right and favours products
What does it mean if Kc is below 1 ?
Conc of reactants is greater than conc of products so equillibrium lies to left and favours reactants
State le Chatelier’s principle
The (position of a dynamic) equilibrium shifts to
minimise (the effect of) any change
What is an abbreviation of the equillibrium constant ?
Kc
What 3 factors are balanced in the chemical industry ?
Rate, economics and safety
