Rates Flashcards
Drawbacks of faster reactions?
- Dangerous
- Costly
The theory that explains how chemical reactions occur and why they occur at different rates.
Collision theory
The minimum energy with which particles must collide in order to cause a chemical reaction.
activation energy
How to increase rate (broad)?
Increase the frequency of successful collisions, by increasing the energy of the particles.
How to increase rate?
- Add catalyst
- Increase temperature
- Increase pressure
- Increase concentration of dissolved reactants
- Increase surface area of solid reactants
Three examples of Catalysts?
Iron –> reaction for ammonia
Enzymes –> Biological systems
Platinum + Palladium –> Catalytic converters in cars
How do catalysts come?
- Powder
- Pellets
- Fine gauzes
How do catalysts work?
Catalysts increase the rate of chemical reactions by lowering the activation energy. The green arrow in the diagram shows the effect of the catalyst. Catalysts achieve this by changing the reaction pathway
Advantages and Disadvantages of catalysts?
Advantage:
- Reduce burning fossil fuels
- Cost effective
Disadvantage:
- Toxicity
Le Chatelier’s principle
Le Chatelier’s principle says that if any of the conditions of a reversible reaction at equilibrium are changed, the system will adapt to counteract whatever has changed.
Decrease temperature
Position of equilibrium shifts towards the exothermic reaction
Increase temperature
Position of equilibrium shifts towards the endothermic reaction
Decrease pressure
Position of equilibrium will shift towards the side with the most molecules of gas being produced
Increase pressure
Position of equilibrium will shift towards the side with the least gas molecules
Increase concentration of reactants
Shift towards the products
