# Kinetics and Equilibria

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1. Particles in liquids and gases are always ____ and ____ with each other.
• Moving
• Colliding
2. A reaction won't take place between two particles unless:
They collide in the right direction. They need to be facing each other the right way

They collide at least a certain minimum amount of kinetic energy
3. What is this called?
Collision Theory
4. The minimum amount of kinetic energy particles need to react is called the _____ _____. The particles need this much energy to ___ the bonds to start the reaction.
• Activation energy
• Break
5. Reaction with ___ activation energies happen pretty easily. But reaction with ___ activation energies don't. You need to give the particles extra ___ by _____ them.
• Low
• High
• Energy
• Heating
6. What is this diagram called and state what happens at each number of the diagram
1 - Here the bonds within each particle are being stretched

2 - If the particles have enough energy, the bonds will break

3 - This is the energy barrier that the particles have to overcome

4 - The separate bits from each particle can't exist by themselves - so they form new bonds and release energy
7. Molecules in a gas don't all have the ___ amount of energy.
Same
8. Name the diagram and what each letter represents.
1 - The curve starts at (0,0) because no molecules have 0 energy

2 - A few molecules are moving slowly

3 - Most molecules are moving at moderate speed so their energies are at this range

4 - Activation Energy

5 - Some molecules have more than the activation energy. These are the only ones that can react
9. Increasing the ______ or ______ makes reactions faster.
• Temperature
• Concentration
10. If you increase the temperature, the molecules will on average have more _____ _____ and will move _____.
• Kinetic energy
• Faster
11. So the greater proportion of molecules have energies greater than the ______ ______ and be able to _____. This changes the _____ of the Maxwell-Boltzmann distribution curve - pushing it to the ____.
• Activation energy
• React
• Shape
• Right
12. And because molecules are moving faster, they'll ____ more often - another reason why ____ temperatures make a reaction faster... and why ___ temperature increases can lead to ____ increases in reaction rates.
• Collide
• Higher
• Small
• Large
13. What other 3 things can affect the reaction rate?
• Conc.
• Surface area
• Catalysts
14. Increasing the conc. of reactants in a _____ or the pressure of a ___ means the particles are ____ together on average. If they are ____ together, they'll _____ more often. More ____ mean more chances to react.
• Solution
• Gas
• Closer
• Closer
• Collide
• Collisions
15. If one reactant is in a big lump, then most the particles won't collide with other reactants. You need to crush these lumps so that more of the particles can come in ____ with the other reactants. A ____particle size means a ____ surface area. This leads to a _____ reaction.
• Contact
• Smaller
• Larger
• Speedier
16. Catalysts are really useful. They _____ the activation energy by providing a ______ ____ for the bonds to be broken and remade. If the activation energy is ____, more particles will have enough _____ to react.
• Lower
• Different way
• Lower
• Energy
17. Catalysts increases the ____ of a reaction by providing an ______ reaction pathway with a _____ activation energy. The catalyst is ______ unchanged at the end of the reaction.
• Rate
• Alternative
• Lower
• Chemically
18. Catalysts are great. They don't get ____ up in reactions, so you only need a _____ ___ of catalyst. catalyse a ____ amount of stuff. they do take part in reactions, but they are ___ at the end.
• Used
• Tiny bit
• Huge
19. Homogeneous Catalysts work by forming _____
Intermediates
20. A homogeneous catalyst is in the _____ state as the reactants. So if the reactants are gases, the catalyst must be a ___ too. And if the reactants are aqueous (dissolved in water), the catalyst has to be ____ as well.
• Same
• Gas
• Aqueous
21. A homogenous catalyst ____ up reactions by forming one or more _____ compounds with the reactants. The products are then formed from the _____ compounds.
• Speeds
• Intermediate
• Intermediate
22. The activation energy needed to form the intermediates (and to form the products from the intermediates) is ____ than that needed to make the products directly from the reactants.
Lower
23. If a reaction is speeded up by a homogeneous catalyst, it's enthalpy profile will have ____ ____ on it.
Two humps
24. The catalyst is ____ again and caries of catalysing the reaction
Reformed.
25. Another way to monitor the rate of reaction when a gas is produced is to stand the reactant vessel on a ____ - the mass will _____ as gas is evolved.
• Balance
• Decrease
26. Not every reaction produces a gas, though. Some produce a _____ that clouds a solution. You can monitor this type of reaction....

What is the problem with this?
Aqueous

By measuring how quickly a marker becomes invisible through the cloudiness

That with this method the result's subjective - different people might not agree over the exact point when the mark 'disappears'. And it only works if the reactants you started with were transparent.
27. Reversible reactions can reach _____ equilibria.
Dynamic
28. In a reversible reaction, as the reactions get used up, the forward reaction _____ _____ - and as more product is formed, the reverse reaction ____ ___.
• Slows down
• Speeds up
29. After a while, the forward reaction will be going at exactly the ____ rate as the backward reaction. This is called dynamic equilibrium.
Same
30. A dynamic equilibrium can only happen in a ____ system. This means that...
Closed

Nothing gets in or out.
31. If you change the ____, ____ or _____ of a reversible reaction, you tend to alter the position of ______. This just means that you'll end up with different amounts of reactants and products at equilibrium.
• Temperature
• Conc.
• Pressure
• Equilibrium
32. If the position of equilibria moves to the left, you get more _____. If it moves more to the right, you get more _____.
• Reactants
• Products
33. Catalysts have _____ effect on the position of equilibrium. They can't increase ____ - but they do mean that equilibrium is reached ____.
• No
• Yield
• Faster
34. If you increase the concentration of a reactant, the equilibrium tires to get rid of the extra reactant. It does this by making _____ _____. So the equilibrium shifted to the ____.
• More product
• Right
35. If you increase the conc. of the product, the equilibrium tries to remove the extra ____. This makes the reverse reaction go _____. So the equilibrium shifts to the ___.
• Products
• Faster
• Left.
36. Increasing the pressure shifts the equilibrium to the side with ___ gas molecules. This _____ the pressure.
• Fewer
• Reduces
37. Decreasing the pressure shifts the equilibrium to the side with ____ gas molecules. This ___ the pressure.
• More
• Raises
38. Increasing the temperature means adding ____.
The equilibrium shifts in the ______ direction to absorb this heat.
• Heat
• Endothermic (Positive Delta H)
39. Decreasing the temperature ____ heat.
The equilibrium shifts in the ______ direction to try and replace the heat.
Removes

Exothermic (Negative Delta H)
40. If the forward reaction's endothermic, the reverse reaction will be ______, and vice versa.
Exothermic
41. Predicting the effect of changing conditions is really important for _____ that use _____ ______. This is because they want to make as much _____ products as possible as cheaply as possible.
• Industries
• Reversible reactions
• Useful
 Author: Jeeten ID: 21317 Card Set: Kinetics and Equilibria Updated: 2010-05-31 14:46:48 Tags: chemistry Folders: Description: Chemistry AS Show Answers: