KINETICS AND COLLISION THEORY

Question 1

according to the collision theory, a reaction can only take place if:

Answer 1

when particles have sufficient energy
when particles collide in the correct orientation (direction)

Question 2

how can you achieve a fast reaction rate

Answer 2

plenty of rapidly moving particles in a small volume

Question 3

why do most collisions between particles not lead to a reaction

Answer 3

dont have sufficient energy
incorrect orientation

Question 4

what is activation energy

Answer 4

minimum amount of energy needed for a reaction to occur

Question 5

describe the energy profile for an exothermic reaction

Answer 5

energy of the products is lower than the energy of the reactants
energy change is negative as energy is released from the reaction into the surroundings

Question 6

describe the energy profile for an exothermic reaction

Answer 6

energy of the products is higher than the energy of the reactants
energy change is positive a energy is absorbed from the surroundings into the reaction

Question 7

how can you provide extra energy to particles

Answer 7

heat

Question 8

what does the maxwell boltzmann distribution show

Answer 8

spread of energies that molecules of a gas have at a particular temperature

Question 9

which particles can react

Answer 9

particles with energy greater than the activation energy

Question 10

what factors can effect the rate of a reaction

Answer 10

concentration
pressure
temp
surface area
catalyst

Question 11

what are catalysts

Answer 11

speeds up the rate of reaction without being used up

Question 12

how do catalysts increase the rate of reaction

Answer 12

providing an alternate reaction pathway
which has a lower activation energy

Question 13

what happens to the amount of energy particles have when a catalyst is introduced

Answer 13

stays the sameq

Question 14

how does increasing temperature affect rate

Answer 14

increasing the temp of a gas will increase the kinetic energy of molecules
means many more particles have energy greater than the activation energy
so more frequent successful collisions

Question 15

how does increasing temp effect MBD

Answer 15

peak is lower and moves to the right
most probable energy will increase as it is more shifted to the right
number of particles with very high energy increases
total area under the curve remains the same
number of particles doesn’t change

Question 16

why does a small increase in temperature lead to a great difference in rate of reaction

Answer 16

many more molecules with energy equal to or greater than activation energy
large increase in number of successful collisions per unit time

Question 17

how does concentration affect rate

Answer 17

increase in concentration means more particles in a fixed volume
particles are closer together
so more frequent successful collisions

Question 18

how does pressure effect rate

Answer 18

increasing pressure means more particles in a fixed volume
so particles are closer together
more frequent and successful collisions

Question 19

how does surface area effect rate

Answer 19

smaller p[articles have a higher SA:V
more particles exposed to other reactant
so more frequent successful collisions

Question 20

how can we increase surface area

Answer 20

crush into powder
cut into smaller pieces
add holes / ridges

Question 21

what happens at the start of a reaction

Answer 21

reaction is fast as there is more frequent collisions

Question 22

what happens to rate as conc of reactant particles decreases

Answer 22

slows down

Question 23

when does a reaction end

Answer 23

when all of one reactant is used up