Collison Theory + Equilibrium

Question 1

Explain what must occur in an reaction of two molecules ? (3)

Answer 1

M1 particles must collide with each other
M2 particles must have sufficient energy
M3 particles must collide in the right orientation

Question 2

Describe and explain the shape of graph with increased temperature (3)

Answer 2

M1 as temperature increases, rate of reaction increases
M2 exponentially
M3 due to more particles have E>Ea , leads to more frequent successful collision

Question 3

How increase concentration affect ROR ?

Answer 3

• more particles available per unit volume
• many more molecules have E>Ea
• more frequent successful collision

Question 4

How does increase surface area affect ROR ?

Answer 4

• many more reactants particles available to react
• more successful frequent collision

Question 5

Why does the curve of Maxwell.Boltzmann distribution starts at origin ?

Answer 5

• because no particles have 0 energy

Question 6

What is the effect of increasing temp. On shape of graph ?

Answer 6

• shift to right with lower peak than normal temp
• More Particles have E> Ea, value of Ea Stay the same , increase frequency of collision

Question 7

What does the area under the distribution curve represent ?

Answer 7

• the total number of molecules present

Question 8

What does higher temp do on the graph ?

Answer 8

• number of particles with E>Ea are in higher proportion
• the peak is lower but total area remain constant

Question 9

What does catalysis do on the ROR graph ?

Answer 9

• causes activation energy to be lower = many more particles have E>Ea = more frequent successful collision = increase ROR
• shape doesn’t change , Ea shift to left slightly

Question 10

Advantages of using catalyst in reactions (4)

Answer 10

• lower energy demand
• less CO2 produced
• les environmental impact
• lower production costs

Question 11

How does catalyse react on help ROR ?

Answer 11

• can happen at same rate but a lower temperature or pressure
• more efficient method

Question 12

State le Chatelier principle

Answer 12

• when a system in equilibrium is disturbed, the position of equilibrium shifts to oppose the change

Question 13

State the meaning of the term catalyst

Answer 13

• a substance that speeds up reaction but chemically not being used up

Question 14

Features of system in state of dynamic equilibrium (4)

Answer 14

M1 both reactions must take place simultaneously
M2 at the same rate
M3 all reactants and products present
M4 concentration remain constant

Question 15

Effect of catalyst in equilibria in reversible reaction

Answer 15

• increases rate of both reactions equally
• has no effect on position of equilibrium but equilibrium is reached faster
• yield of products remain unchanged