REACTION KINETICS
Reactants --> Products
E.g.
2H2 + O2 --> 2H2O
CHEMICAL REACTION
1. Reactants must collide into each other
2. Collision must be of enough energy
3. Reactants must collide in a specific orientation
4. Old bonds break in reactants, new bonds form in products.
Effective Collision - Results in the formation of a product.
Activation energy - Minimum amount of energy required for a reaction to start.
***Exothermic reactions give out energy, and endothermic reactions take in energy.
BONDS
BEN --> Breaking is endothermic BB - Bond Breaking
MEX --> Making is exothermic BM - Bond Making
--> If BB energy is more than BM energy, then the reaction is endothermic. A+B = C
--> If BM energy is more than BB energy, then the reaction is exothermic.
REACTANTS
ACTIVATED INTERMEDIATE
Activation energy
Change in thalapy
PRODUCT
Factors affecting rate of reaction
1. Catalysts (decrease activation energy required)
2. Concentration (more particles, more collision between particles)
3. Temperature (temp increases, collision of particles increases)
4. Size of particle (larger particle, less surface area for collision)
5. Pressure (in gaseous state) (more particles per unit volume, more collisions)
Catalysts - Supply the alternate path in a reaction, hence decreasing activation energy.
RATE OF REACTION =
Increase/decrease in mass/volume
time
** Increase in product concentration
** Decrease in reactant concentration
Figure 1. Catalysts
With every 10 degrees Celsius increase in temperature, the rate of reaction doubles.
Change in mass/volume
Time
Reaction 2 (faster reaction)
Reaction 1 (slower reaction)
Reaction 2 is faster because of the following possibilities:
- It has smaller particles
- It has higher concentration/pressure
- Higher temperature
- Catalyst might have been used