Kinetics I Flashcards
(10 cards)
How does increasing the concentration affect the rate of reaction?
The number of particles in the same volume are increased so the particles are closer together and collide more frequently, so there will be more successful collisions per unit time.
How does increasing the pressure of a gas affect the rate of reaction?
The concentration of the gas molecules increases as the same number of gas molecules occupy a smaller volume. The gas molecules are closer together and collide more frequently, leading to more successful collisions per unit time.
What is the rate of reaction?
rate = change in concentration / time
Why does the rate of reaction slow down as the reaction proceeds?
Because the reactants are being used up and their concentrations decrease.
What is a homogenous catalyst?
A catalyst that has the same physical state as the reactants.
What is a heterogenous catalyst?
A catalyst that has different physical state to the reactants.
What is the purpose of a catalytic converter?
To oxidise the hot exhaust fume gases in cars - carbon monoxide to carbon dioxide and nitrogen monoxide to nitrogen gas - to make them less harmful.
What is autocatalysis?
When a chemical reaction has a product which acts as a catalyst for that reaction.
What happens to the rate of reaction when temperature is increased?
More molecules have an energy greater than or equal to the activation energy
Therefore a greater proportion of collisions will lead to a reaction, increasing the rate of reaction.
How does the use of a catalyst affect the rate of reaction?
Provides an alternative reaction route with a lower activation energy.
Then a greater proportion of molecules now have an energy greater than or equal to the lower activation energy
more successful collisions
