C6 Flashcards
What is a closed system
A closed system is a vessel in which nothing gets in or out
What happens at dynamic equilibrium?
A + B ->-< C
What is the effect of catalysts on equilibrium?
A catalyst does not change the position of the equilibrium, it only increases the rate of the forward and reverse reaction equally, allowing them to reach equilibrium faster.
What happens to the equilibrium when the temperature increases/decreases?
When the temperature increases, the equilibrium will favour the endothermic reaction, therefore will shift to the direction of the products that the endothermic reaction produced. Conversely, when the temperature is decreases, the equilibrium will favour the exothermic reaction, therefore will shift to the side of the products of the exothermic reaction.
What happens to the equilibrium when the pressure is increased/decreased?
When the pressure is increased, the equilibrium will favour the reaction that produced the least moles of substance, therefore will shift to the side with the least moles. Conversely, if the pressure is decreased, the the equilibrium will favour the reaction that produces the most moles of substances, therefore will shift to the side that produces the most moles of substances;
What happens to equilibrium when concentration is increased/decreased?
When the concentration of a substance is increased, the equilibrium will favour the reaction that does not produce that substance but uses it up as a reactant, therefore will shift to the side which that substance does not appear. Conversely, when the concentration of a substance is decreased, the equilibrium will favour the reaction which produces that substance as a product, therefore will shift to the side that that product is on
What is the conditions used for the Haber Process?
450 degrees, 200atm, iron catalyst
Why are the conditions for the Haber process used?
The temp is 450 as a lower temp will give a higher yield of ammonia as the forward reaction is exothermic, however if the temp is too low, the rate of reaction will be too slow, therefore a compromise temperature of 450 is used. A pressure of 200atm is used because if you increase the pressure, the equilibrium will shift to the right to decrease the pressure, therefore increasing the yield of nh3, however, a pressure any higher will become to expensive to produce a higher yield to become worth it, therefore a compromise pressure of 200atm is chosen. An iron catalyst is chosen as it will increase the rate of reaction of both the forward and reverse reaction, meaning that you don’t need to increase the temp or pressure as much to achieve a faster rate of reaction, saving money.
What is the effect on increasing/decreasing temp on the Kc?
If the forward reaction is exothermic, increasing the temperature will cause more of the reverse reaction to occur, therefore the equilibrium will shift to the left and increase the amount of reactants, which will decrease the Kc as that is products/reactants. Conversely, if you decrease the temp when the forward reaction is exothermic, the equilibrium will shift to the left, causing more products to be produced, therefore the Kc will increase. However, if you increase the temp when the forward reaction is endothermic, the equilibrium will shift to the right, which will increase products and increase Kc. If you decrease the temp when the forward reaction is endo, then more of the reverse reaction will occur, therefore the equilibrium will shift to the left, increasing reactants and decreasing Kc.
What is the effect of changing concentration and pressure on Kc?
Nothing, Kc will stay constant.
