3.2.2: Reaction rates Flashcards
1
Q
Factors affecting rate of reaction
A
- Temperaature
- Pressure/concentration
- Catalyst
- Surface area
- UV/some appropriate wavelength
2
Q
How to measure rate of reaction
A
Measure colour/concentration/volume/pH against time
3
Q
Effect of increasing concentration on rate of reaction
A
- ↑ concentration = more collisions
- More likely successful collisions per unit time
- Increased rate of reaction
4
Q
Effect of increasing temperature on rate of reaction
A
- ↑ temperature = particles move faster, collide more often
- Higher proportion have higher kinetic energy
- More successful collisions
5
Q
How do catalysts work?
A
- Provide a different pathway for the reaction
- One or more of the reactants combines with the catalyst to form an activated complex. The formation of this activated complex requires less Eᴬ than the uncatalysed reaction
- The activated complex reacts to form the products
6
Q
What would happen if the catalyst bound tightly and irreversibly?
A
- Products would never get released
* Catalyst will be contaminated (not work)
7
Q
Two types of catalyst
A
- Heterogeneous catalysts
* Homogeneous catalysts
8
Q
Heterogeneous catalysts
A
in a different phase to the reactants they catalyse.
9
Q
Homogeneous catalysts
A
in the same phase to the reactants they catalyse.
10
Q
Example of heterogeneous catalyst
A
Hydrogenation of vegetable oils to make margarine –> uses Ni catalyst
11
Q
Example of homogeneous catalyst
A
Acid catalysed esterification of a carboxylic acid
