2.9 Kinetics Flashcards
(16 cards)
What is a reaction rate?
A reaction rate is a measure of how quickly a reaction takes place.
How can we measure reaction rate?
We can measure how quickly a reactant is used up or how quickly a product is formed.
How is reaction rate mathematically expressed?
Reaction rate = change in recorded property / time
What does reaction rate indicate?
The reaction rate indicates the change of the concentration (amount) of a reactant or product with respect to time.
What does the collision theory explain?
The collision theory explains why only a small proportion of collisions between reacting particles lead to a reaction and how certain factors affect the reaction rate.
What must occur before a chemical reaction can take place?
The reacting particles must collide.
What are the two factors that determine if reacting particles will react after colliding?
- The reacting species must approach each other in the correct orientation.
- The reacting species must have a certain minimum amount of energy, known as the Activation Energy, Ea.
What are the two main ways to increase the rate of a reaction?
- Increase the number of collisions between reacting particles.
- Increase the amount of energy that reacting particles have.
What factors can affect the rate of a chemical reaction?
- Concentration
- Temperature
- Pressure
- Catalysis
How can altering reaction conditions affect the rate of reaction?
Altering reaction conditions can affect the rate of reaction, which can be explained with reference to collision theory.
What effect does increasing the concentration of a reactant have on the rate of reaction?
Increasing the concentration of a reactant usually results in the rate of reaction increasing.
Example: In the reaction of calcium carbonate with hydrochloric acid, increasing the concentration of hydrochloric acid leads to more successful collisions with calcium carbonate.
How does changing pressure affect the rate of reaction?
Changing pressure only affects reactions involving gaseous reactants. Increasing the pressure leads to an increased rate of reaction due to more successful collisions in a smaller volume of space.
What is the effect of increasing temperature on reaction rate?
Increasing the temperature of a reaction leads to an increase in reaction rate because more particles have energy greater than the activation energy.
In general, increasing the temperature by 10 °C can result in the reaction rate doubling.
What is a catalyst?
A catalyst increases the rate of a reaction but does not get used up. They are specific to individual reactions and help reduce costs in industrial processes.
How do catalysts speed up reactions?
Catalysts speed up reactions by providing an alternative reaction pathway of lower activation energy.
What is activation energy?
The activation energy is the minimum amount of energy required for a reaction to occur.
