Topic 4 - Inorganic Chem & Periodic Table Flashcards
Inorganic Chemistry and the periodic table
1
Q
Why does ionisation energy decrease down G2 ? (reactivity increases)
A
- extra electron shell (shielding)
- outer electrons further away from the nucleus (lower electrostatic attraction)
2
Q
What are the solubility trends depending on the compound anion?
A
- Group 2 elements that contain single charged negative ions INCREASE in solubility down the group
- Compounds that contain double charged negative ions DECREASE in solubility down the group
3
Q
What happens when G2 burns in oxygen ?
A
produces metal oxides (solid white)
4
Q
What is the solubility trends as you go down Group 2 when you react with hydroxide?
A
Increases down the group
5
Q
What happens when G2 reacts with chlorine ?
A
produces metal chlorides (solid white)
6
Q
Which G2 does not produce an alkaline when added to water ?
A
- beryllium (oxide) - doesn’t react with water
beryllium (hydroxide) - insoluble - magnesium (oxide) - reacts slowly
magnesium (hydroxide) - low solubility
7
Q
What is the solubility trends as you go down Group 2 when you react with sulfate?
A
Decreases down the group
8
Q
What sulfate is insoluble in water?
A
Barium sulfate
9
Q
What are compounds like magnesium hydroxide known to be ?
A
sparingly soluble because they have a low solubilty
10
Q
EQUATION when metal oxides react with water
A
MO(s) + H2O(l) -> M(OH)2(aq)
11
Q
EQUATION when metal hydroxides react with water
A
M(OH)2(s) –+H2O(l)–>M(OH)2(aq)
12
Q
EQUATION when metal hydroxides react with dilute acid
A
M(OH)2(aq) + 2HCl(aq) –> MCl2 (aq) +2H2O(l)
13
Q
EQUATION when metal oxides react with dilute acid
A
MO(s) +2HCl(aq) –> MCl2(aq) + H2O(l)
14
Q
What is the flame colour of Li?
A
Red
15
Q
Trend of thermal stability in G1 and G2 ?
A
increases down a group
16
Q
What is the flame colour of Na?
A
orange/yellow
17
Q
What is the flame colour of K?
A
lilac
18
Q
What is the flame colour of Rb?
A
red
19
Q
What is the flame colour of Cs?
A
blue
20
Q
How are G1/G2 carbonate and nitrate ions made unstable ?
A
they are large anions made unstable by the presence of a cation as it polarises the anion (distorting it) - greater distortion = less stable
21
Q
What is the flame colour of Ca?
A
brick-red
22
Q
What is the flame colour of Sr?
A
crimson
23
Q
What is the flame colour of Ba?
A
green
24
Q
How do you do a flame test in 3 steps:
A
- MIX a small amount of the compound you’re testing with a few drops of hydrochloric acid.
2.HEAT a piece of platinum or nichrome wire in a hot Bunsen flame to clean it
3.DIP the wire into the compound/acid mixture. Hold it in a very hot flame and note the colour produced.
25
What causes most distortion ?
smaller cations - higher charge density
26
Why do bunsen burners produce different colours depending on the compound used?
Energy absorbed from flame= electrons move to higher energy levels.
Colours seen as the electrons fall back down to lower energy levels=release energy in the form light.
Difference in energy as electron move from higher and lower levels determines the wavelength of the light released= makes the colour of the light.
27
EXPLAIN the trend in thermal stability of G1/G2 ?
further down the group = larger cation = lower charge density = less distortion = more stable carbonate/nitrate ion
28
Which compounds are more thermally stable ? (G1 or G2)
Group 1
29
Why are G2 compunds less thermally stable than G1 compunds ?
- the greater the charge on cation, the greater the distortion and less stability
- G2 have +2 charge compared to a +1 charge
- therefore less stable
30
How to test the thermal stability of nitrates.
1. measure how long it takes until a certain amount of oxygen is produced
2. measure how long until an amount of brown gas is produced
31
How to test the thermal stability of carbonates
1. how long it takes for an amount of CO2 to be produced
CO2 test- add limewater which is a saturated solution of calcium hydroxide.Turns cloudy
32
Do Group 1 carbonates decompose? and if they do which one can decompose.
they are thermally stable - you can't heat them w a bunsen burner to make them decompose
HOWEVER THERE IS ALWAYS ONE SPECIAL ONE, Li2CO3 which decomposes to Li2O and CO2
33
Do Group 2 carbonates decompose?
they do decompose and they form an oxide and carbon dioxide
General formula: MCO3 --> MO + CO2
E.g. CaCO3 --> CaO + CO2
34
Do G2 nitrates decompose ?
yes - forms metal oxide, nitrogen dioxide and oxygen
general formula : 2M(NO3)2
----> 2MO + 4NO2 + O2
35
What is the colour of fluorine?
pale yellow
36
What type of reaction is a halogen and halide reaction?
redox (displacement)
37
Explain the displacement reaction between halogens and halides (in terms of redox)
Thing being displaced is oxidised
Thing that does displacing is reduction
38
What is the colour of chlorine?
green
39
What is the colour of bromine?
red-brown
40
What is the colour of iodine?
grey
41
What is the physical state of fluorine?
gas
42
What is the physical state of chlorine?
gas
43
What is the physical state of bromine?
liquid
44
ionic equation for chlorine water (Cl2) (colourless) + potassium chloride (KCl) (colourless)
no reaction
45
What is Halogens natural state they exist in?
Covalent Diatomic Molecules
46
Are Halogens polar or non- polar and why?
Non-polar because they have low solubility in water
47
Colour of chlorine when in water and hexane
both virtually colourless
48
ionic equation for chlorine water (Cl2) (colourless) + potassium bromide (KBr) (colourless)
Cl2 + 2(Br)- ---> 2(Cl)- + Br2
orange
49
Colour of bromine when in water and hexane
yellow/orange and orange/red
50
Colour of Iodine when in water and hexane
Brown and pink/violet
51
ionic equation for chlorine water (Cl2) (colourless) + potassium iodide (KI) (colourless)
Cl2 + 2(I)- ---> 2(Cl)- + I2
brown
52
ionic equation for bromine water (Br2) (orange) + potassium chloride (KCl) (colourless)
no reaction
53
ionic equation for bromine water (Br2) (orange) + potassium bromide (KBr) (colourless)
no reaction
54
ionic equation for bromine water (Br2) (orange) + potassium iodide (KI) (colourless)
Br2 + 2(I)- ---> 2(Br)- + I2
brown2
55
ionic equation for iodine solution (I2) (brown) + potassium chloride (KCl) (colourless)
no reaction
56
ionic equation for iodine solution (I2) (brown) + potassium bromide (KBr) (colourless)
no reaction
57
ionic equation for iodine solution (I2) (brown) + potassium iodide (KI) (colourless)
no reaction
58
How to make the colour changes of halogen-halide reactions easier to see ?
shake reaction mixture with and organic solvent eg hexane
halogen will dissolve in organic solvent and settle out as a distinct layer above the aqueous solution
59
Reactivity trend of group 7 ?
less reactive down group
60
What 'agent' are halogens in terms of redox
oxising agents - usually react by gaining an electron therefore are reduced and oxidise other substance
61
Explain the reactivity trend of group 7 ?
atoms become larger = electrons further away = shielding = harder for nucleus to attract electron to form ion
62
what is the trend for melting and boiling point in G7
increases down the group
63
EXPLAIN the trend for mp/bp in G7
increase in electron shells = stronger London forces = harder to overcome intermolecular forces
64
Which halides will chlorine replace
bromide and iodide
65
which halides will bromine replace
iodide
66
which halide will iodide replace
none
67
what happens when you mix cold chlorine gas and dilute aqueous sodium hydroxide
bleach is formed
68
Trend of reducing power in halides ?
increases down the group
69
EXPLAIN the trend of reducing power of halides ?
attraction of the outermost electron and nucleus weakens down the group (shielding and distance) therefore are oxidised more easily
70
what happens when halides react with concentrated sulfuric acid?
produces hydrogen hallide
71
explain the reaction of KF or KCl with H₂SO₄ ? include equation
KF (s) + H₂SO₄ (l) →KHSO₄ (s) + HF (g)
- misty fumes seen as gas comes into contact with moisture in air
- fluoride/chloride ions not strong enough reducing agents to reduce H₂SO₄ therefore reaction stops
- oxidation numbers stay the same = not redox
72
explain the reaction of KBr with H₂SO₄ ? include equation
reaction 1: KBr (s) + H₂SO₄ (l) →KHSO₄ (s) + HBr (g)
reaction 2: 2HBr (aq) + H₂SO₄ (l) →Br₂ (g) + SO₂ (g) + 2H₂O (l)
- first = misty fumes
- second = bromide ions stronger reducing agents = redox reaction
- second = choking fumes of SO₂ and orange fumes of Br₂
73
When halides react with H₂SO₄ what oxidation states should be assessed?
halide and sulfur
74
explain the reaction of KI with H₂SO₄ ? include equation
reaction 1: KI (s) + H₂SO₄ (l) →KHSO₄ (s) + HI (g)
reaction 2: 2HI (g) + H₂SO₄ (l) → I₂ (s) + SO₂ (g) + 2H₂O (l)
reaction 3 : 6HI (g) + SO₂ → H₂S (g) + 3I₂ (s) + 2H₂O
- first = same initial reaction
- second = iodide ion reduce H₂SO₄
- third = iodide ions very strong reducing agent therefore keeps going and reduces SO₂ to H₂S
- third = H₂S gas is toxic and smells of bad eggs
75
What type of gas are hydrogen halides ?
acidic
76
What happens when hydrogen halides dissolve in water ?
produces misty fumes of acidic gas (can happen with moisture in air)
77
What happens when hydrogen halides react with ammonia gas ?
white fumes produced
78
What can be used as a test for halide ? and why
addition of silver ions as coloured precipitate formed
79
Describe the test for halide ions ?
1. add dilute nitric acid to remove ions that may interfere with reaction
2. add silver nitrate solution
3. precipitate of silver halide formed
80
What happens when fluoride is added to silver nitrate solution ?
no precipitate as AgF is soluble
81
What colour precipitate is formed when chloride reacts with silver nitrate ?
white (milk)
82
What colour precipitate is formed when bromide reacts with silver nitrate ?
cream (cream)
83
What colour precipitate is formed when iodide reacts with silver nitrate ?
yellow (butter)
84
Why is a test for halide solutions difficult to identify when silver nitrate added ?
colours are very similar
85
What can be added to the silver nitrate test for halide ions ?
ammonia solution
86
What happens when silver chloride (white) reacts with ammonia solution ?
dissolves to give colourless solution
87
What happens when silver bromide (cream) reacts with ammonia solution ?
precipitate remains unchanged = dilute ammonia
dissolves and colourless = concentrated ammonia
88
What happens when silver iodide (yellow) reacts with ammonia solution ?
does not dissolve even in concentrated ammonia solution
89
Describe the test for carbonate ions (CO₃²⁻) or hydrogencarbonate ions (HCO₃⁻)
1. when either react with hydrochloric acid they fizz as carbon dioxide produced
2. test for carbon dioxide with limewater = turns it cloudy
3. bubble gas though test tube of limewater and watch
90
Describe the test for sulfates (the sulfate ion SO₄²⁻ )
1. add dilute hydrochloric acid followed by barium chloride solution
2. HCl added to remove traces of carbonate ions from previous test as would also produce a precipitate
3. if sulfate ions present in original compound, white precipitate of barium sulfate formed
91
Describe the test for ammonium compounds - include equation
1. add sodium hydroxide in a test tube with supposed compound with NH₄⁺
2. heat gently
3. hold damp litmus paper over test tube and if NH₃ given off should turn blue
NH₄X (aq) + NaOH (aq)→NH₃ (g) + H₂O (l) + NaX (aq)
