Chemistry- Unit 2- Kinetics.

HideShow resource information
  • Created by: FireDwarf
  • Created on: 18-01-14 15:39
What is kinetics?
Study of factors which affect rate of reactions.
1 of 25
What is collision theory? What needs for it to take place?
For a reaction to take place between two particles, they must collide. They must collide with enough energy to break the bond & they must be correctly orientated for it to occur.
2 of 25
What do most collisions cause?
No reaction- either they collide with not enough energy or in the incorrect orientiation.
3 of 25
How do we increase the rate of chemical reactions?
Temperture, conc of a solution, pressure of a gas, surface area of solid reactants, catalyst.
4 of 25
How does temperture do it?
Provides the particles with more kinetic energy- increases the speed & energy- increases likelyhood of successful collision.
5 of 25
Conc of solution?
More particles per given volume, increased likelyhood of a successful collision. BUT as time goes on, conc decreases. Rate of reaction would therefore fall as reaction continues.
6 of 25
Pressure of a gas?
More molecules, increased likelyhood of a collision.
7 of 25
Surface area
More particles able to collide with each other at any given time, therefore increased likelyhood and speed of successful collisions.
8 of 25
Catalyst
Gives an alternative path for a reaction, decreases the energy needed for particles to react, more successful reactions.
9 of 25
What is this minimum energy called?
Activation energy (Ea).
10 of 25
What is the energy of products in comparrision to reactants in exo & endo?
Products less in exo, products more in endo.
11 of 25
What is the name given to the graph demostrating the distribution of particles with diffrent energies?
Maxwell-Boltzman distribution.
12 of 25
Why do particles have varied energies?
Because they all have varied speeds and E is in a relationship with speed
13 of 25
What does the graph tell us?
No particles have 0 energy. Most have an intermediate energy- peak of curve. Few have high energy.
14 of 25
What is the average energy not the same as?
The most probable.
15 of 25
How does the graph look?
We see a dramatic increase, a peak, then a dramatic decrease. The line does not touch the x axis as it decreases.
16 of 25
Where are the particles with the Ea?
The area under the curve which passes the Ea point (paricles with higher energy).
17 of 25
Effect of temp on graph?
Increase the temperture, see more particles with more energy, so curve moves more to the right. Decrease, more to the left.
18 of 25
Effect of concentration?
Increase conc, more particles, the curve is therefore more dramatic.
19 of 25
How does a catalyst work?
By providing an alternative pathway, therefore decreasing the activation energy needed for a successful collision.
20 of 25
What are the two types of catalyst?
hetrogenous & homogeneous
21 of 25
What do they mean?
Hetro, are in a diffrent phase to reactants (usually a solid catalyst). Homo- same phase.
22 of 25
What are diffrent phases?
When a phase is seperated by a distinct boundary.
23 of 25
How does the catalyst in a catolytic convertor work?
Gases form weak bonds with the metal atoms during absorbtion. Holds gases in the right place for them to react on the surface. Products then break away from metal atoms, desorption.
24 of 25
Importance about the strengh of bonds between catalyst and gases?
Strong enough to hold it in the right place to react but weak enough so it can break away.
25 of 25

Other cards in this set

Card 2

Front

What is collision theory? What needs for it to take place?

Back

For a reaction to take place between two particles, they must collide. They must collide with enough energy to break the bond & they must be correctly orientated for it to occur.

Card 3

Front

What do most collisions cause?

Back

Preview of the front of card 3

Card 4

Front

How do we increase the rate of chemical reactions?

Back

Preview of the front of card 4

Card 5

Front

How does temperture do it?

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all Kinetics resources »