Kinetics

Question 1

What is the activation energy of a reaction?

Answer 1

The minimum energy required to start a reaction by the breaking of bonds

Question 2

What is required for a reaction to start?

Answer 2

The colliding particles must have energy greater than the activation energy

Question 3

What is the rate of reaction?

Answer 3

The change in concentration of a substance, in a given time.

Question 4

What are the units for the rate of resction?

Answer 4

moldm-3 s-1

Question 5

How do you calculate the rate of reaction at a particular point on a rate graph?

Answer 5

Calculate the gradient lf the tangent to the curve at that point

Question 6

State 5 factors that can affect the rate of reaction

Answer 6

Concentration
Pressure
Surface area
Temperature
Catalysts

Question 7

Explain how concentration effects the rate of reaction

Answer 7

If conc. increases, rate increases
There are more particles per unit volume
More frequent successful collisions per unit time

Question 8

Explain how pressure increases the rate of reaction

Answer 8

If pressure of gases increases, rate increases
More gas particles per unit volume
More frequent successful collisions

Question 9

Explain how surface area increases the rate of reaction

Answer 9

More surfaces are exposed to other reacting particles
More frequent successful collisions

Question 10

Explain how temperature affects the rate of reaction?

Answer 10

Increased temp increases rate
Many more particles have energy greater than the activation energy, and move quicker
More frequent successful collisions per unit time

Question 11

What is a catalyst

Answer 11

A catalyst increases the rate of reaction without being changed in chemical composistion or amount

Question 12

Explain how a catalyst increases the rate of reaction

Answer 12

Catalysts privide an alternative route with a lowered activation energy.
So many more particles have energy greater than the lowered activation energy, leads to more frequent successful collisions per unit time

Question 13

What is the Maxwell-Boltzmann distribution?

Answer 13

A graph that shows the distribution of energies of colliding particles during a reaction, as energy is exchanged

Question 14

Describe the key features on the Maxwell-boltzmann distribution graph

Answer 14

• highest peak is most probable energy (Ep)
• average energy (Eaverage) is always to the right of Ep
• activation energy (Ea) is on the right
• graoh shows energy againts number of particles

Question 15

What does the area under the curve show on a maxwell-boltzmann distribution curve?

Answer 15

The total number of particles

Question 16

What does the area under the curve show on a maxwell-boltzmann distribution curve?

Answer 16

The total number of particles

Question 17

Why does the curve never touch the x-axis on a maxwellboltzmann distribution curve?

Answer 17

Because no particle can have 0 energy

Question 18

How will an increases temperature effect a maxwell-boltzmann distillation curve?

Answer 18

The peak will shift to the right and down
The area under the curve will remain the same
The area within the activation energy will increase
The average energy will increase

Question 19

How will a catalyst affect the Maxwell-Boltzmann distribution curve?

Answer 19

The curve will remain the same, yet the activation energy will shift to the left. The area under the curve within the activation energy will increase