1.5 Kinetics

Question 1

What is the collision theory?

Answer 1

The particles of the reactants need to collide having frequent successful collisions above the activation energy

Question 2

What is rate of reaction?

Answer 2

Frequency of collisions of the reactant particles at or above the activation energy

Resulting in a change in concentration of products or reactants over a given period of time

Question 3

What must happen in order for a successful chemical reaction to take place?

Answer 3

Particles must:
Collide
Collide with enough energy
Collide with the correct orientation

Question 4

The is the activation energy?

Answer 4

The minimum amount of energy particles must have to start a reaction

Question 5

What factors affect rate of reaction?

Answer 5

Temperature*
Concentration
Surface area
Catalysts

Question 6

How does temperature affect the rate of reaction?

Answer 6

It gives the particles more kinetic energy. The vibrate and move more at a greater force causing more frequent collisions above the activation energy. Increasing the rate of reaction

Question 7

How does concentration affect the rate of reaction?

Answer 7

Higher concentration means there are more particles in a given volume therefore more opportunities for successful frequent collisions. This will increase the rate of reaction

Question 8

Which has a higher surface area? Marble chips or Marble powder

Answer 8

Marble powder

Question 9

How does surface area affect the rate of reaction?

Answer 9

A higher surface area means there are more particles exposed to the acid so there are more successful frequent collisions above the activation energy. This will increase the rate of reaction

Question 10

What does a catalyst do?

Answer 10

It lowers the activation energy
By providing an alternative reaction pathway

Allowing more successful frequent collisions above the activation energy

Question 11

What is a catalyst?

Answer 11

It speeds up a chemical reaction and doesn’t get used up

Question 12

Are catalysts used up in a reaction? How can you tell?

Answer 12

No, they have the same mass at the start and end of the reaction

Question 13

Are catalysts costly? Economical?

Answer 13

Expensive but economical as they don’t need replacing often

Question 14

Why are catalysts important in industrial processes?

Answer 14

To reduce the energy which will reduce the costs and environmental impact

Question 15

How can we link temperature to rate of reaction?

Answer 15

For every 10 degree increase the rate of reaction approximately doubles

Question 16

What graphs can we use to show rates of reactions?

Answer 16

Maxwell-Boltzmann Distributions

Question 17

What are the labels on the Maxwell-Boltzmann Distribution graphs?

Answer 17

Number of particles - up the side

Energy- along the bottom

Question 19

What does the Maxwell-Boltzmann curve look like?

Answer 19

Very steep initially
Gradual decline

=asymmetrical

Question 20

What is the highest peak on the Maxwell-Boltzmann curve?

Answer 20

The most probable energy a particle will have as it is the most frequent i.e mode

Question 21

What are some factors of the Maxwell-Boltzmann curve?

Answer 21

The area under the curve represents the total number of particles in the sample
The curve starts at the origin
The curve never touches the bottom x axis again = asymptote

Question 22

Why does the Maxwell-Boltzmann curve never touch the x axis after the start?

Answer 22

That would imply the particles have a finite amount of energy but particles have the potential for an infinite amount of energy