Chapter 8 - Reactivity Trends

Question 1

What is a reducing agent?

Answer 1

A species that donates it’s electrons to another species, thereby reducing that species.

Question 2

Which group are reducing agents commonly found?

Answer 2

Group 2
(Be, Mg, Ca, St, Br)

Question 3

What is the trend in reactivity down group 2?

Answer 3

Reactivity increases. (This is because the further away an electron is from the nucleus)

Question 4

Explain the trend of reactivity down group 2

Answer 4

Increased atomic radius and shielding effect so ionisation energies decrease. Therefore it’s easier to lose electrons.

Question 5

What are the products of a group 2 element reacting with water? metal + water = ?

Answer 5

metal + water = Metal hydroxide and hydrogen

Question 6

What is the product of a group 2 element reacting with oxygen? metal + oxygen = ?

Answer 6

metal + oxygen = Metal oxide

Question 7

group 2 metal oxide + water = ?

Answer 7

group 2 oxide + water = metal hydroxide

Question 8

What is the trend of solubility down group 2?

Answer 8

Increases

Question 9

Explain the trend of solubility down group 2

Answer 9

Down the group, the solution has a greater concentration of OH-.

Question 10

Given that group 2 oxides, hydroxides and carbonates neutralise acids, what can they be referred to as?

Answer 10

Bases

Question 11

Given that most group 2 oxides, hydroxides and carbonates are soluble in water, what are they also besides bases?

Answer 11

Alkalis

Question 12

What is the use of calcium hydroxide in agriculture?

Answer 12

Increases the pH of acidic soils.

Ca(OH)(2) + 2H+ -> Ca2+ + 2H(2)O

Question 13

How are group 2 compounds used in medicine?

Answer 13

Used in indigestion tablets as antacids, often a suspension of a metal hydroxide in water.

Question 14

What is another name for group 2?

Answer 14

Alkaline Earth Metals

Question 15

What is another name for group 7?

Answer 15

Halogens

Question 16

What is the trend in boiling point down group 7?

Answer 16

Increases

Question 17

Explain the trend in boiling point down group 7

Answer 17

More electrons,
Stronger induced dipole-dipole forces,
More energy to break intermolecular forces,
Boiling point increases.

Question 18

What is the trend in reactivity down group 7?

Answer 18

Reactivity decreases

Question 19

Explain the trend in reactivity down group 7

Answer 19

Atomic radius increases,
More inner shells,
Shielding increases,
Nuclear attraction decreases,
Reactivity decreases.

Question 20

What do more reactive halogens do to less reactive halide ions?

Answer 20

Displace them

Question 21

What can displacement reactions be used to identify?

Answer 21

Which halide is present in solution.

Question 22

Which compound is used to test for halides?

Answer 22

Silver nitrate solution. AgNO3

Question 23

How can the results for a halide test be further tested?

Answer 23

Solubility in ammonia solution

Question 24

What is disproportionation?

Answer 24

A redox reaction in which the same element is both oxidised and reduced.

Question 25

Describe the test for carbonates

Answer 25

Carbonates react with acids to form carbon dioxide gas. Add dilute nitric acid to testing solution. If bubbles observed could be a carbonate. To prove its CO(2), bubble gas through lime water, limewater turns cloudy (milky) .

Question 26

Describe the test for sulphates

Answer 26

the test for sulphates is to add Aqueous barium nitrate to the solution. If a white precipitate forms, there is a sulphate.

Question 27

In the halide tests, what happens to chloride with silver nitrate and then ammonia

Answer 27

chlorine Silver nitrate - white precipitate Ammonia - soluble in dilute ammonia

Question 28

In the halide tests, what happens to bromide with silver nitrate and then ammonia

Answer 28

Silver nitrate - cream precipitate | Ammonia - soluble in concentrated ammonia

Question 29

In the halide tests, what happens to iodide with silver nitrate and then ammonia

Answer 29

(AgNO3) Silver nitrate - yellow precipitate | Ammonia - insoluble in concentrated ammonia

Question 30

What is the correct order for these anion tests?

Answer 30

Carbonate test, sulphate test, halide test C.S.H

Question 31

Why is this the correct order for anion tests carbonate, sulphate, halide?

Answer 31

Carbonates also form a white precipitate in the sulphate test but not vice versa. Carbonates and sulphates form precipitates with silver nitrate. CSH

Question 32

Describe the test for ammonium ions

Answer 32

Add aqueous NaOH (sodium hydroxide) to the solution, Ammonia gas is produced, Can be detected with moist indicator paper as it will turn blue.

Question 33

the test for halide ions table?

Answer 33