✅9 - Kinetics I

Question 1

What is collision theory?

Answer 1

Particles must collide to react

Question 2

What are the criteria for particles to react?

Answer 2

They must collide in the right orientation

They must collide in with the minimum amount of kinetic energy

Question 3

What is activation energy?

Answer 3

The minimum amount of kinetic energy needed to for the particles to react

Question 4

What is a reaction profile diagram?

Answer 4

Shows the progress of the reaction over time, with the energy of the reactants and products

Question 5

What happens when the temperature is increased?

Answer 5

Reactions progress faster

Question 6

How does higher temperature change the Maxwell-Boltzman distribution?

Answer 6

It moves to the right

Question 7

Why does increasing temperature speed up a reaction?

Answer 7

The molecules have more kinetic energy and so collide more often

Question 8

Why does increasing concentration speed up a reaction?

Answer 8

If you increase the concentration of reactants in solution, there are more particles in a given volume of the solution, so they collide more frequently

Question 9

Why does increasing pressure speed up a reaction?

Answer 9

If any of the reactants are gases, there are more molecules of the gas in the volume so there are more successful collisions

Question 10

Why do catalysts speed up reactions?

Answer 10

They lower the activation every by providing a different way for bonds to be broken, and then more molecules have the required energy to react

Question 11

What does rate of reaction tell you?

Answer 11

How fast reactants are converted to products

Question 12

How can rate of reaction be worked out?

Answer 12

From the gradient of a graph

Question 13

How would you calculate gradient?

Answer 13

Change in y / change in x

Question 14

How would you work out the gradient of a curved graph?

Answer 14

By drawing a tangent

Question 15

How can you work out the initial rate of reaction?

Answer 15

By calculating the gradient of the intial part of the graph

Question 16

How can you work out rates of reaction from experimental data?

Answer 16

amount of reactant used or amount of product made/time taken

Question 17

What is the rate of reaction proportional to?

Answer 17

1/time

Question 18

Why does a catalyst increase the rate of reaction?

Answer 18

By providing an alternative pathway for the reaction

Question 19

What is a benefit of using a catalyst?

Answer 19

They don;t get used u in reactions so only a small amount is needed

Question 20

What is a disadvantage of using a catalyst?

Answer 20

They are very specific

Question 21

What is a heterogeneous catalyst?

Answer 21

One in a different phase to the reactants

Question 22

What do solid heterogeneous catalysts provide?

Answer 22

A surface for the reaction to take place on

Question 23

How do heterogeneous catalysts work?

Answer 23

The reactant molecules are adsorped, then the bonds are weakened and the new molecules are formed. Then, they are desorped

Question 24

What is a homogeneous catalyst?

Answer 24

One in the same physical state as the reactants

Question 25

How do homogeneous catalysts work?

Answer 25

They combine with the reactants to make an intermediate species, then forming the products

Question 26

What economic benefits do catalysts have?

Answer 26

They lower costs of production, make more products in a shorter time and make better products

Question 27

What catalyst is used in ammonia production?

Answer 27

Iron

Question 28

How does polyethene behave when made without a catalyst?

Answer 28

It is less dense and less rigid

Question 29

How does polyethene behave when made with a catalyst

Answer 29

It is more dense, more rigid and has a higher melting point

Question 30

What does the Maxwell-Boltzmann distribution show?

Answer 30

The proportion of particles with a certain amount of energy