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Flashcards in Chapter 8 Deck (47)
1

List 2 group 2 elements

Mg
Ca

2

Are group 2 elements oxidising or reducing agents?

Reducing agents

3

How can group 2 elements act as reducing agents?

Can lose 2 electrons to become oxidised (2+ ions) when reducing another species

4

Metal + O2 --> ?

Metal oxide

5

Metal + H2O --> ? + ?

Metal hydroxide + H2

6

Metal + acid --> ? + ?

Salt + H2

7

Write an equation for the reaction of magnesium with oxygen

2 Mg + O2 --> 2 MgO

8

Write an equation for the reaction between magnesium and water

Mg + 2 H2O --> Mg(OH)2 + H2

9

Write an equation for the reaction between magnesium and hydrochloric acid

Mg + 2 HCl --> MgCl2 + H2

10

Describe the trend in reactivity as you go down Group 2

Reactivity increases
Ionisation energy decreases due to increased shielding / increased atomic radius
Decreased nuclear attraction between the outer electrons and the nucleus

11

Describe the trend in solubility (of hydroxides) as you go down Group 2

Solubility increases because solutions contain more OH-, increasing the pH and alkalinity

12

Give 2 uses of Group 2 compounds?

Agriculture
Medicine

13

What group 2 compound can be used in agriculture?

Ca(OH)2 added to fields to increase the pH of acidic soils

14

What group 2 compound can be used in medicine?

CaCO3
Mg(OH)2

Used in medicines for heartburn and indigestion

15

Describe the trend in boiling point as you go down the halogen group

Boiling point increases
More electrons
Stronger London forces
More energy required to overcome these forces

16

Describe the trend in reactivity as you go down the halogen group

Reactivity decreases
Atomic radius/shielding increases
Less nuclear attraction to capture an electron from another species
Hence, reactivity decreases

17

What type of reaction shows that the reactivity of the halogens decreases down the group?

Halogen-halide displacement reactions

18

Describe how a halogen-halide displacement reaction would be carried out

1) Solution of each halogen added to (aq) solutions of the other halides
2) Reaction takes place and solution changes colour

19

What is the most reactive halogen?

Cl-
Reacts with both Br- and I-

20

What is the least reactive halogen?

I-
Doesn't react with either Cl- or Br-

21

What colour is seen in a solution of bromine in water?

Orange

22

What colour is seen in a solution of iodine in water? (before cyclohexane is added)

Orange-brown

23

What colour is a solution of iodine in water, after cyclohexane is added?

Violet

24

What can you add to solutions of iodine and bromine in water to tell the 2 colours apart?

Non-polar solvent
e.g. cyclohexane

25

Are the halogens polar or non-polar?

Non-polar

26

What is a disproportionation reaction?

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

27

Write an equation for the reaction of chlorine with water (disproportionation reaction)

Cl2 + H2O --> HClO + HCl

28

Write an equation for the reaction of chlorine with cold, dilute NaOH (disproportionation reaction)

Cl2 + 2 NaOH --> NaClO + NaCl + H2O

29

What is a use of chlorine?

Purifies water

30

What is an implication of using chlorine to purify water?

Chlorine is a respiratory irritant

31

What 3 tests are involved in qualitative analysis of anions, in order?

Carbonate test
Sulfate test
Halide test

32

Describe the carbonate test

1) Add dilute acid (HNO3)
2) Effervescence indicates carbonate ions

33

What test can you use to check that the gas produced in the carbonate test is CO2?

Lime water test
CO2 turns lime water cloudy

34

Write an equation for the reaction between sodium carbonate and nitric acid

Na2CO3 + HNO3 --> NaNO3 + CO2 + H2O

35

Describe the sulfate test

1) Add a solution containing Ba 2+ ions
2) White precipitate indicates sulfate

36

Write an equation for the reaction between Barium ions and sulfate ions

Ba 2+ + SO4 2- --> BaSO4 (s)

37

What indicates the presence of sulfate ions?

White precipitate

38

Describe the halide test

1) Add solution containing Ag+ ions (AgNO3)
2) Precipitates of silver halides form
3) Add NH3 (aq) to test the solubility of precipitates formed

39

What colour precipitate is silver chloride?

White

40

What colour precipitate is silver bromide?

Cream

41

What colour precipitate is silver iodide?

Yellow

42

What conditions is silver chloride soluble in?

Soluble in dilute NH3 (aq)

43

What conditions is silver bromide soluble in?

Soluble in conc. NH3 (aq)

44

What conditions is silver iodide soluble in?

None.
Insoluble in conc. NH3 (aq)

45

Describe the test for cations (NH4+)

1) Add NaOH
2) Ammonia gas is released
3) Turns indicator blue because ammonia is alkaline

46

Write the equation for the reaction between NH4+ and OH-

NH4+ + OH- --> NH3 + H2O

47

Why must the sulfate test be carried out AFTER the carbonate test?

BaCO3 also produces a white precipitate