3.2.7-12 : Rate Of Reaction And Chemical Equilibrium

Question 1

What is required for a chemical reaction to occur successfully?

Answer 1

Reactant particles must collide with energy greater than or equal to the activation energy and with correct orientation.

Activation energy is the minimum energy required for two particles to react.

Question 2

What is activation energy?

Answer 2

The minimum amount of energy required for two particles to react.

Essential for understanding collision theory in chemical reactions.

Question 3

How do reaction conditions affect reaction rates?

Answer 3

They can be altered to give particles more energy, increasing the likelihood of effective collisions.

This leads to a greater rate of reaction.

Question 4

Fill in the blank: Chemical reactions occur when _______ collide.

Answer 4

reactant particles

Question 5

True or False: The orientation of colliding particles does not affect the success of a chemical reaction.

Answer 5

False

Question 6

What happens when the conditions of a reaction are optimized?

Answer 6

The rate of reaction increases due to a greater likelihood of effective collisions.

Optimizing conditions can include changes in temperature, pressure, and concentration.

Question 7

What happens to molecules when a substance is heated?

Answer 7

Molecules move faster and further due to increased thermal energy converted to kinetic energy.

This increased movement results in more frequent collisions.

Question 8

How does increased temperature affect the rate of reaction?

Answer 8

It increases the rate of reaction due to more frequent successful collisions with energy greater than the activation energy.

Higher temperatures lead to more collisions occurring.

Question 9

What is the effect of increasing concentration on the rate of reaction?

Answer 9

It increases the rate of reaction because more molecules in the same volume lead to more likely collisions.

The probability of collisions with sufficient energy also increases.

Question 10

How does increasing pressure affect the rate of reaction in gases?

Answer 10

It increases the rate of reaction as molecules are packed closer together in a smaller volume.

This results in a higher likelihood of collisions.

Question 11

What is the effect of surface area on the rate of reaction?

Answer 11

Increasing surface area leads to more exposed reactant particles, resulting in more frequent successful collisions.

An example is crushing a reactant into a powder.

Question 12

Fill in the blank: Increased movement of molecules means _______.

Answer 12

collisions occur more often and with greater energy.

Question 13

True or False: Increasing temperature decreases the reaction rate.

Answer 13

False

Question 14

Fill in the blank: More molecules in the same volume due to increased concentration mean _______.

Answer 14

collisions between molecules become more likely.

Question 15

What is the activation energy?

Answer 15

The minimum energy required for a reaction to occur.

Question 16

What is a catalyst?

Answer 16

A substance that increases the rate of reaction without being used up in the reaction.

Question 17

How does a catalyst work?

Answer 17

By providing an alternative reaction path with a lower activation energy.

Question 18

Why are catalysts used in industry?

Answer 18

Because they lower the energy costs of the reaction process.

Question 19

What advantages do catalysts provide in terms of temperature and pressure?

Answer 19

They allow lower temperatures and pressures to be used while still achieving the same rate of reaction.

Question 20

What is atom economy in relation to catalysts?

Answer 20

Catalysts can give a higher atom economy.

Question 21

Why are catalysts considered economically important?

Answer 21

Because they lower energy costs and improve efficiency in chemical processes.

Question 22

How do catalysts contribute to sustainability?

Answer 22

By lowering temperatures and reducing energy demand from combustion of fossil fuels.

Question 23

What environmental benefit do catalysts provide?

Answer 23

A reduction of CO2 emissions.

Question 24

True or False: All catalysts are non-toxic.

Answer 24

False.

Question 25

Fill in the blank: A catalyst provides an alternative reaction path with a lower _______.

Answer 25

activation energy.

Question 26

What negative effect must be weighed against the benefits of improved sustainability from catalysts?

Answer 26

The toxicity of some catalysts.

Question 27

What represents the dip in the energy profile for a catalysed reaction?

Answer 27

The intermediate formed during the reaction ## Footnote The intermediate is less stable and higher in energy than the reactants and products.

Question 28

Define homogeneous catalysts.

Answer 28

Catalysts that are in the same phase as the reactants

Question 29

Define heterogeneous catalysts.

Answer 29

Catalysts that are in a different phase to the species in the reaction

Question 30

Give an example of a heterogeneous catalyst.

Answer 30

Solid iron catalyst in the Haber Process

Question 31

Why do transition metals make good catalysts?

Answer 31

They have variable oxidation states

Question 32

What occurs when electrons are transferred in a reaction with transition metal catalysts?

Answer 32

A reactive intermediate is produced, speeding up the reaction rate

Question 33

What is an example of a transition metal catalyst?

Answer 33

Vanadium oxide in the contact process

Question 34

Fill in the blank: Transition metals have _______ oxidation states.

Answer 34

variable

Question 35

True or False: Homogeneous catalysts are in a different phase than the reactants.

Answer 35

False

Question 36

What is the role of the catalyst in the Haber Process?

Answer 36

To speed up the reaction between hydrogen and nitrogen gases

Question 37

What does the contact process convert sulfur dioxide into?

Answer 37

Sulfur trioxide

Question 38

What is the primary function of a solid catalyst?

Answer 38

To adsorb molecules onto an active site on its surface

Question 39

How do active sites on a catalyst affect molecular interactions?

Answer 39

They increase the proximity of molecules and weaken covalent bonds

Question 40

What is the result of weakening covalent bonds in molecules during a reaction?

Answer 40

Reactions occur more easily and the rate is increased

Question 41

In what context are solid catalysts typically used?

Answer 41

In industry to provide a surface for reactions to occur on

Question 42

Fill in the blank: A solid catalyst works by _______ molecules onto an active site.

Answer 42

[adsorbing]

Question 43

True or False: Solid catalysts only function in laboratory settings, not in industry.

Answer 43

False