Different reactions (free radical, competitive etc.) Flashcards
What is a competitive reaction?
Reactions that are parallel
What is the yield of a competitive reaction worked out by?
Using the rate constants
When working out the yield of a competitive reaction, what goes on the bottom of the equation and what goes on the top?
Top - the rate constant of the steps that lead to the product
Bottom - the rate constant of the steps that lead to the product and the rate constant of the competitive steps
What is important in a competitive reaction?
The use of a catalyst to control product distribution
What is there a need for in competitive reactions?
Need to eliminate side reactions
What is there no need for in competitive reactions?
No need to be fast as it all depends on the relative rates
What could have important effects when looking at competitive reactions?
Temperature
If we have different EA terms
What is the effect of a catalyst?
To lower the activation energy at a specific temperature
What is a consecutive reaction?
The reactants form an intermediate species, which subsequently reacts to form the product
What does the ability to observe the intermediate depend on?
The relative rates for its formation and decay
What are the three parts of a graph for a consecutive reaction where A -> I -> B?
- Decay of the reactant A
- Growth and subsequent decay of the intermediate
- Appearance of the product B
In the reaction A -> i -> B, what does the rate constant KAI lead to?
Increase in the concentration of the intermediate
In the reaction A -> i -> B, what does the rate constant KIB lead to?
Decrease in the concentration of the intermediate
Write the differential equation for the intermediate species in consecutive reactions?
d[I]/dt = KAI [A] - KIB [I]
What is best to focus on in consecutive reactions?
Better to focus the attention on the behaviour of the intermediate
