Kinetics Flashcards
What is kinetics?
Is the study of the factors that affect rate of chemical reactions -
how quickly they take place
What factors that affect the rate of reaction?
> Increasing the temperature
Increasing the concentration of a solution
Increasing the pressure of a gas reaction
Increasing the surface area of solid reactants
Using a catalyst
What is collision theory?
> For a reaction to take place between two particles, they must collide with enough energy to break bonds. (particles need to move fast)
> The collision must also take place
between the parts of the molecule that are going to react together and the right orientation
> To get a lot of collisions you need a lot
of particles in a small volume.
In terms of collision theory - What does collision say when particles collide and don’t react?
> They either do not have enough energy
> They are in the
wrong orientation.
How does a catalyst increase the rate of reaction?
A catalyst is a substance that can change the rate of a chemical reaction without being chemically changed itself.
How does increasing temperature, increase the rate of chemical reactions?
This increases the speed of the molecules, which in tum increases both their energy and the number of collisions.
How does increasing the concentration/pressure of a solution, increase the rate of reaction?
If there are more
particles present in a given volume then collisions are more likely and the reaction rate would be faster.
How does increasing the surface area of a solid reactant, increasing the rate of reaction?
The greater the
total surface area of a solid, the more or its particles are available to collide with molecules in a gas or a liquid. So faster the rate of reaction because more sites of reaction
What is activation energy?
The minimum energy needed to start a reaction (Ea)
What does Maxwell-Boltzmann distribution tell us?
It tells us about the distribution of energy amongst the particles.
What is a catalyst?
Are substances that affect the rare of chemical reactions
without being chemically changed themselves at the end of the reaction.
What are the advantages of using a catalyst?
It is cheaper to speed up a reaction by using a
catalyst than by using high temperatures and pressures
How do catalyst work to increase the rate of reaction?
By providing a different pathway for the
reaction, one with a lower activation energy. Therefore they reduce
the activation energy of the reaction
- Not a flashcard - catalyst *
How does using a catalyst affect the Maxwell-distribution-curve
How does a catalytic converter work?
The gases first form weak bonds with the metal atoms of the
catalyst - this process is called adsorption. This holds the gases in
just the right position for them to react together. The gases then react on the surface.
The products then break away from the metal atoms - this process is called desorption. This frees up room on the catalyst surface for more gases to take their place and react.
