3.1.5 Kinetics Flashcards
when can reactions only occur
when collisions takes place and the particles have sufficient energy
what is the activation energy
the minimum energy which particles need to collide to start a reaction
what is maxwell boltzman distribution
shows the spread of energies that molecules of a gas or liquid have at a particular temp
what is the x axis on a maxwell boltzman distribution
collision energy
what is the highest peak on the maxwell boltzman distribution
the most probable energy
what is the second line after the most probable energy
the mean energy of the particles
what is the area under the curve on the maxwell boltzman distribution
the total number of particles present
why does the maxwell distribution curve go through 0,0
there are no molecules with no energy
/ zero energy
what is the third line on the maxwell boltzman distribution curve
the activation energy
how can a reaction go to completion if few particles have energy greater than Ea
particles can gain energy through collisions
what is meant by the term rate of reaction
the change in concentration of a substance in unit time
what happens to the maxwell D curve when you increase the temperature
it shifts to the right
why is the MBD curve wider when we increase the temperature
the molecules have a wider range of energies
explain what happens to the rate of reaction when we increase the concentration and pressure
it increases
there are more particles per unit volume
-particles collide with greater frequency
- higher frequency of collisions
how will the curve look like when we increase the concentration
the curve would be higher
if a question mentions a doubling of concentration/rate
then make sure you mention double the number of particles
per unit volume and double the frequency of effective
collisions.
when comparing the rate curve when theres a higher concentration/temp/surface area how does the curve look like
its steeper
what happens to the rate of reaction when we increase the temperature
at higher teemps the particles have more kinetic energy
they have energy greater than the activation energy
and there are more collisions
explain what happens to the rate of reaction when we increase the surface area
collisions occur more frequently
what is a catalyst
they increase the rate of reaction without being used up
how do catalysts increase the rate of reaction
they provide an alternative route with a lower activiation energy
what happens when the activation energy is low
more particles have energy greater than the activation energy
- so more frequent collisions
where does the Ea shift on a MBD curve when a catalyst is present
it shifts to the left
what is the reaction profile when a catalyst is added
it starts and ends at the products and reactants bit
but the hump is lower than the original one.
