Flashcards
Equilibrium Year 1 and 2
Cards in this deck (25)
- 1At equilibrium which reaction is faster, the forwards or backwards reaction? Why does the concentration of products and reactants not change at equilibrium? What is a DYNAMIC, equilibrium system? What is a closed system? And why is it required?-They are both equal to each other.
-They do not change because there is products constantly being produced and reversed so the concentration never changes as along as the forward and backward reactions equal.
-A system in which both the forward and back reactions are taking place at the same time resulting in the concentration not changing.
-A closed system is when the reaction is isolated from it surroundings, this is needed to prevent the reactants or products reacting with molecules outside the equilibrium. - 2What happens as the reactants gets used up in an equilibrium reaction?-More product is formed causing the forward reaction to slow down and the backwards reaction to increase. As more reactants are being made, the backward reaction slows down gradually and then stops once equilibrium is reached.
- 3What is Le Chatelier's PrincipleIf there is a change in the concentration, pressure or temperature, the equilibrium will shift to minimise the effects of the change.
- 4By Le Chatelier's Principle what happens when you: -increase the concentration of reactants -decrease the concentration reactants-If you increase the concentration of reactants the equilibrium will shift to the side of the products this will make more products and get rid of the extra reactants.
-If you decrease the concentration of products the equilibrium will shift to the side of the reactants to make more reactants returning the reaction to equilibrium - 5By Le Chatelier's Principle what happens when you: increase the concentration of products decrease the concentration of products-If you increase the concentration of products the equilibrium will try to remove the extra product, it does this by shifting to the side of the reactants this will make reactants from the extra products returning it to equilibrium.
-By decreasing the concentration of products the equilibrium will shift to the side of the product to make more products returning the reaction to equilibrium - 6By Le Chatelier's Principle what happens when you: increase the concentration of products decrease the concentration of products
- 7By Le Chatelier's Principle what happens when you: increase the temperature decrease the temperature-By increasing temperature your adding heat, so the equilibrium will shift in the endothermic direction to absorb the excess heat.
-By decreasing the temperature your removing heat, so the equilibrium shifts in the exothermic direction to replace the heat being lost. - 8By Le Chatelier's Principle what happens when you: increase the temperature decrease the temperature
- 9By Le Chatelier's Principle what happens when you: increase the pressure decrease the pressure-If you increase the pressure the equilibrium will shift to the side with the least number of gas molecules.
-If you decrease the pressure the equilibrium to increase the pressure again the equilibrium will shift to the side with the most gas molecules - 10By Le Chatelier's Principle what happens when you: increase the pressure decrease the pressure
- 11What do catalysts do? Why do catalysts not affect the position of the equilibrium?-They increase the rate of the forward and backwards reaction.
-They don't affect it because a catalyst speeds up both the forward and backwards reaction by the same amount, so it only increases the speed/rate of reaction and will not effect the equilibrium. - 12Which conditions are chosen for compromise in production in industries?
- 13What is Kc/Kp? What factor would you have to use to investigate the position of Kc/Kp?-Kc and Kp are the equilibrium constants.
-You would have to use temperature because Kc is only affected by temperature. - 14What is the purpose of the equilibrium constant (Kc)? What is the expression used to work out Kc? What does Kc<1, Kc>1, and Kc=1 tell us about the products/reactants?-It is used to determine if there is more products than reactants or more reactants than product
-When aA + bB ⇄ cC + dD, then,
Kc = ([C]^c[D]^d)/([A]^a[B]^b)
-If Kc<1 there are more reactants
If Kc>1 there are more products
If Kc = 1 they're the same - 15What does the expression of Kc actually mean and why are we doing it? What does Kc<1, Kc>1, and Kc=1 tell us about the equilibrium position?-It means the concentration of products divided by the concentration of reactants, we are doing it to determine the position of the equilibrium.
-If Kc<1 then the equilibrium lies more to the reactants
If Kc>1 then the equilibrium lies more to the products
If Kc = 1 then the equilibrium lies halfway between the reactants and products - 16What is a bronsted-lowry acid? What is a bronsted-lowry base?-A proton donor
-A proton acceptor - 17What is conjugate acid-base pair?-Two species which only differ by a H+ ion (By a proton)
E.g H2SO4 and HSO4-
NH4+ and NH3
HC2H3O2 and C2H3O2- - 18What would you do to workout the equilibrium constant if the reaction is: Homogeneous? Heterogeneous?-If it is Homogeneous you do the normal concentration of products over concentration of reactants.
-If it is Heterogeneous you would have to do the products of GAS and AQEUOUS substances only over reactants of GAS and AQEUOUS substances - 19What is the Kc equation? Rearrange Kc to work out the [Products]? Rearrange Kc to work out the [Reactants]?
![What is the Kc equation? Rearrange Kc to work out the [Products]? Rearrange Kc to work out the [Reactants]?](https://examtimeassets.s3.amazonaws.com/uploads/media/image/20160010/desktop_52c199ca-f69e-4276-bf6e-67f6f571ab2b.png)
- 20What factors affect the equilibrium'S position? What factors affect Kc/Kp, explain why?-Concentration, Temperature, Pressure
-Kc is only affected by temperature - 21If Kp/Kc are only affected by temperature, why would they TEMPORARILY change when there is an increase/decrease in pressure/concentration/ETC? Why is the change only temporary?-This is because Kp/Kc is not affected. The change is caused in value by factor affecting the equilibrium (Pressure/Concentration/Temperature).
-It is temporary because the equilibrium will shift to the opposite side to oppose the change in the factor which will cause Kp/Kc to rise back to its original value - 22Describe the procedures used to investigate the change temperature has on the position of the equilibrium?1) Place 2 sealed test tubes of the equilibrium mixture in hot and cold water.
2) In the hot water bath the colour of the mixture will be dark brown, the heat from the water bath is being absorbed and used to produce the brown colour
3) In the cold bath the mixture will be colourless, this is because bonds are being broken to release heat and make the colourless substance. - 23Describe the procedures used to investigate the change concentration has on the position of the equilibrium?
- 24What is homogeneous equilibria? What is heterogeneous equilibria?-Homogenous equilbiria is when the equilibrium contains species which are all in the same state.
-Heterogenous equilibrium is when the equilibrium contains species which are in different states - 25Why does Kc only include the concentration of gases and aqueous species?-This is because concentration solids and liquids remain fairly constant during reactions, so when the equilibirum shifts the change is basically still 1, therefore they are neglible.
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- Flashcards on Equilibrium Year 1 and 2, created by BUKDABOSS . on 27/11/2018.
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