Chp 8

Question 1

Oxidation

Answer 1

Gain of electrons
Loss of oxygen

Question 2

Reduction

Answer 2

Loss of oxygen
Gain of electrons

Question 3

Oxidising agent

Answer 3

Oxidises smth else
Removes electron
Reduced itself

Question 4

Reducing agent

Answer 4

Reduces smth else
Donating an electron
Oxidised itself

Question 5

disproportionation reaction

Answer 5

when the same species undergoes oxidation + reduction

Question 6

ON decrease

Answer 6

reduction

Question 7

ON increase

Answer 7

oxidation

Question 8

Combustion equation for grp 1

Answer 8

4M (s) + O2 (g) > 2M2O (s)

Question 9

Cl gas w grp 1

Answer 9

2M (s) + Cl2 > 2MCl (s)

Question 10

Li + Na + K reactions with water

Answer 10

Li > fizzing / float on water
Na > fizzing / melt in ball
K > lilac flame

2M (s) + 2H2O (l) > 2MOH (aq) + H2 (g)

Question 11

combustion equation for grp 2

Answer 11

2M (s) + O2(g) > 2MO (s)

Question 12

chlorine + grp 2

Answer 12

M (s) + Cl2 (g) > MCl2 (s)

Question 13

grp 2 w water

Answer 13

Mg + h20 = slow reaction
down group increase in reactivity
Mg react in steam

Question 14

Grp 1 + 2 oxides

Answer 14

• Grp 1 + 2 are basic
• react with water to form colourless solutions of alkali
• Grp 1 > M2O (s) + h20 (l) > 2MOH (aq)
• Grp 2 > MO (s) + h20 (l) > M(OH)2 (aq)

IONIC > o2- + h20 > 2OH -

Question 15

hydroxides

Answer 15

• PH of alkali depend on solubility of metal hydroxide
• solubility increase DOWN group
• MgOH = insoluble
• BaOH = soluble > more acidic
• Ca(OH)2 > water - CaCO3 (test for limewater)
• Mg(OH)2 > for suspension (indigestion remedy)

All grp 1 + 2 oxides (OH) react w acid
form salt + water > neutralisation reaction
white solid + colourless liquid + exothermic

Question 16

Sulfates in grp 2

Answer 16

• solubility of sulfates DECREASE down grp

MgSO4 = soluble
CaSO4 = slightly soluble
SrSO4 = insoluble
BaSO4 = insoluble (reason why used to test for sulfate ion)

Question 17

thermal stability

Answer 17

measure of how stable compound is when heated

not decompose: thermally stable
decompose: not stable

No3- + CO3 2- larger than other anions / more complex / larger / more likely to decompose

Question 18

NO3- decomposing

Answer 18

NO3- decompose into nitrite (NO2-) + oxide (O2-)

Oxygen + Nitrogen dioxide (NO2) gas

Question 19

CO3 2- decomposing

Answer 19

CO3 2- smaller and more stable oxide
O2- release oxygen gas

Question 20

carbonates

Answer 20

grp 1 + 2 carbonates are white solids

do not decompose / decompose to oxide (II)

oxide > white solid
Co2 > colourless

metal carbonate > metal oxide + co2

grp 2 decompose as they are small and highly charged Li as well

Question 21

nitrates

Answer 21

grp 1 + 2 nitrates are white solids
> decompose to nitrite (III) or oxide (II)

forms metal nitrate&raquo_space; metal nitrite + oxygen

No2 gives of brown fumes
o2 > steam

no brown fumes > less decomposition
brown fumes > more decomposition

metal nitrate > metal oxide + o2 + NO2

All grp 2 nitrates form brown fumes > small size + high charge
only lithium from grp 1

Question 22

test for ammonium ions

Answer 22

ammonia (NH4+) has no colour in flame test
NaOH added + mixture warmed
ammonia reacts to form ammonia gas
ammonia gas will turn damp red litmus paper blue

or mix ammonia with HCl to form white solid