3.1.5 Kinetics

Question 1

when can reactions only occur

Answer 1

when collisions takes place and the particles have sufficient energy

Question 2

what is the activation energy

Answer 2

the minimum energy which particles need to collide to start a reaction

Question 3

what is maxwell boltzman distribution

Answer 3

shows the spread of energies that molecules of a gas or liquid have at a particular temp

Question 4

what is the x axis on a maxwell boltzman distribution

Answer 4

collision energy

Question 5

what is the highest peak on the maxwell boltzman distribution

Answer 5

the most probable energy

Question 6

what is the second line after the most probable energy

Answer 6

the mean energy of the particles

Question 7

what is the area under the curve on the maxwell boltzman distribution

Answer 7

the total number of particles present

Question 8

why does the maxwell distribution curve go through 0,0

Answer 8

there are no molecules with no energy
/ zero energy

Question 9

what is the third line on the maxwell boltzman distribution curve

Answer 9

the activation energy

Question 10

how can a reaction go to completion if few particles have energy greater than Ea

Answer 10

particles can gain energy through collisions

Question 11

what is meant by the term rate of reaction

Answer 11

the change in concentration of a substance in unit time

Question 12

what happens to the maxwell D curve when you increase the temperature

Answer 12

it shifts to the right

Question 13

why is the MBD curve wider when we increase the temperature

Answer 13

the molecules have a wider range of energies

Question 14

explain what happens to the rate of reaction when we increase the concentration and pressure

Answer 14

it increases
there are more particles per unit volume
-particles collide with greater frequency
- higher frequency of collisions

Question 15

how will the curve look like when we increase the concentration

Answer 15

the curve would be higher

Question 16

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.

Question 17

when comparing the rate curve when theres a higher concentration/temp/surface area how does the curve look like

Answer 17

its steeper

Question 18

what happens to the rate of reaction when we increase the temperature

Answer 18

at higher teemps the particles have more kinetic energy
they have energy greater than the activation energy
and there are more collisions

Question 19

explain what happens to the rate of reaction when we increase the surface area

Answer 19

collisions occur more frequently

Question 20

what is a catalyst

Answer 20

they increase the rate of reaction without being used up

Question 21

how do catalysts increase the rate of reaction

Answer 21

they provide an alternative route with a lower activiation energy

Question 22

what happens when the activation energy is low

Answer 22

more particles have energy greater than the activation energy
- so more frequent collisions

Question 23

where does the Ea shift on a MBD curve when a catalyst is present

Answer 23

it shifts to the left

Question 24

what is the reaction profile when a catalyst is added

Answer 24

it starts and ends at the products and reactants bit
but the hump is lower than the original one.