Unit 1: Chemical Changes and Structure

Question 1

If a reaction is too fast, what can happen?

Answer 1

Thermal explosion

Question 2

What effects will increasing the rate of reaction have?

Answer 2

Quicker production

Larger yield/profit

Question 3

What six factors can affect the rate of reaction?

Answer 3

Catalyst
Temperature
pH
Concentration
Pressure
Particle size

Question 4

Why will smaller particle size lower the rate of reaction?

Answer 4

Greater surface area, more of the reactant is exposed and will see more successful collisions

Question 5

What is the rate of reaction?

Answer 5

The change in concentration of reactants or products in unit time

Question 6

On a graph, how can we tell the reaction is finished?

Answer 6

The curve levels out because the reactants have been used up

Question 7

What is the formula used to find the relative rate of a reaction?

Answer 7

Relative Rate = 1 over time

Question 8

What is the formula used to find the average rate of reaction?

Answer 8

Average rate of reaction = change in quantity over change in time

Question 9

If the same reaction occurs in a higher temperature than before, what will happen to the activation energy?

Answer 9

It will increase

Question 10

A piece of phosphorus ignites when touched with a hot wire, while magnesium ribbon needs strong heating before it will catch fire.
What does this suggest about the activation energies of the two elements?

Answer 10

The magnesium has a higher activation energy as more heat is needed to start the reaction

Question 11

What is needed for two particles to collide (react)?

Answer 11

Correct energy and correct collison geometry

Question 12

A reaction that loses energy is… ?

Answer 12

Exothermic

Question 13

A reaction that absorbs energy is… ?

Answer 13

Endothermic

Question 14

If the reaction is endothermic then the enthalpy change will be… ?

Answer 14

Positive

Question 15

If the reaction is exothermic then the enthalpy change will be… ?

Answer 15

Negative

Question 16

What is the difference in potential energy between reactants and products called?

Answer 16

Enthalpy change

Question 17

What is calculated from the reactants to the tip of the graph?

Answer 17

Activation energy

Question 18

What is Ea?

Answer 18

Activation Energy

Question 19

What is a catalyst?

Answer 19

A substance that alters the rate of reaction without being used up itself

Question 20

What catalyst is used in the Haber process?

Answer 20

Iron

Question 21

What catalyst is used in the Ostwald process?

Answer 21

Platinum

Question 22

What is produced in the Haber process?

Answer 22

Ammonia

Question 23

How does a catalyst affect the activation energy?

Answer 23

It lowers it, making the reaction quicker

Question 24

What is group 0 or 8 commonly known as?

Answer 24

The Noble gases

Question 25

What are the elements of Group 7 known as?

Answer 25

The Halogens

Question 26

Name all the diatomic elements

Answer 26

Iodine, Bromine, Chlorine, Fluorine, Oxygen, Nitrogen, Hydrogen

Question 27

How is the periodic table arranged?

Answer 27

In order of increasing atomic mass

Question 28

Which group on the periodic table consists of monotomic elements?

Answer 28

Group 0/8 (the noble gases)

Question 29

How are metallic atoms delocalised?

Answer 29

Because the outer electrons are loosely held

Question 30

How are covalent bonded elements held together?

Answer 30

By the attraction between their positive nuclei and negatively-charged shared pairs of electrons

Question 31

What makes a covalent bond non-polar?

Answer 31

If the bonding electrons are shared equally

Question 32

What are London Dispersion Forces?

Answer 32

Very weak forces of attraction which can operate between all atoms and molecules

Question 33

How are temporary dipoles formed?

Answer 33

Through the uneven distribution of the constantly moving electrons around the nuclei of the atoms

Question 34

Are LDF intermolecular or intramolecular?

Answer 34

intermolecular

Question 35

What is a covalent network?

Answer 35

A huge structure where each atom is covalently bonded to other atoms

Question 36

What are the three covalent network elements?

Answer 36

Carbon (graphite), boron and silicon

Question 37

Which will react quicker in concentrated nitric acid: Copper powder, or copper turnings?

Answer 37

Copper powder (surface area)

Question 38

What is activation energy?

Answer 38

The minimum amount of kinetic energy required for a reaction to take place.