Topic 9 Kinetics

Question 1

What is required for a reaction to occur

Answer 1

Particles collide with sufficient energy (>= activation energy) and with the right orientation

Question 2

What is rate of reaction

Answer 2

Change of concentration or amount of substance per unit time

Question 3

What do Maxwell Boltzmann distributions show

Answer 3

Energy in gas particles in a system

Question 4

What 4 things happen to a Maxwell B distribution when temp increases

Answer 4

1. Curve moves right
2. Peak is lower
3. Area stays the same
4. Area below the curve past activation energy increases

Question 5

What 5 things affect rate

Answer 5

1. Conc
2. Temp
3. Surface area
4. Pressure
5. Presence of a catalyst

Question 6

What is the difference between homogeneous and heterogeneous catalysts

Answer 6

Homo - same phase
Hetero - different phase

Question 7

How do heterogeneous catalysts work

Answer 7

Reactants adsorb onto the surface of the solid catalyst. Radicals form as bonds are weaker and then radicals react to form new particles. New molecules desorb from the surface

Question 8

How do homogeneous catalysts work?

Answer 8

They provide alternative multi step reaction route with lower total activation energy.

Question 9

How are homogeneous catalyst energy profile diagrams different

Answer 9

They have 2 activation energies

Question 10

3 reasons to use a catalyst in industry

Answer 10

• lower temperature less money of fuel and less environmental impact
• speed up reaction - time is money
• change properties of a product

Question 11

2 environmental reasons to use a catalyst

Answer 11

1. Lower temp and pressure required reduces waste
2. Catalyst reactions may have better atom economy so less waste is created

Question 12

3 ways to measure rate

Answer 12

1. Time to form ppt
2. Mass loss over time
3. Volume of gas collected over time