equilibrium Flashcards
features of a reaction at dynamic equilibrium? (2)
- rate of forward reaction is equal to the rate of the backward reaction
- the concentrations of reactants and products remain constant
- only occurs in closed systems where no substances can get in or out
le chateliers principle states…
when a system is subject to change, the system will alter to lessen the effect of that change
Increasing temperature of a reaction does what?
favours the endothermic reaction (+ve AH) as the excess heat needs to be removed from the system to lessen the effect of the initial increase.
- It will increase the yield of the endothermic products.
decreasing temperature favours the…
exothermic reaction (-ve AH) as heat needs to be gained and the yield of the exothermic products will be increased.
Increasing pressure favours…
the side of the reaction with fewer moles of gas, as this will help to release the built up in pressure. It will increase the yield of the products on the side of the reaction with the fewest moles of gas.
decreasing pressure favours…
the side of the reaction with more moles as pressure has been lost.
- The yield of the products on this side of the reaction will be increased.
Increasing the concentration of the reactants will favour…
the reaction direction that produces the products as more molecules are available to react.
- It will increase the yield of the products.
decreasing the concentration of products will favour… the reaction that reforms the reactants.
the reaction that reforms the reactants.
how do catalysts effect the position of equilibrium?
Catalysts appear not to affect the equilibrium position as they affect the forward and backward reaction equally.
- However, they do allow equilibrium to be reached faster
Kc is equal to…
the concentration of the products divided by the concentration of the reactants.
The value of Kc is not affected by…
concentration change or use of a catalyst,
the value of Kc is affected by…
changing the reaction temperature
The rate of reaction is increased by increases in…
temperature, pressure or concentration.
