CCEA GCSE Chemistry Unit 2 Revision Notes includes: metals and the reactivity series, redox, rusting and iron, rates of reaction, organic chemistry, quantitative chemistry II, electrochemistry, energy changes in chemistry and gas chemistry.
Chemistry 2
Metals and the Reactivity Series
The more reactive a metal is, the more vigorously it reacts, and the more easily to loses
Metal Reaction with oxygen when Reaction at Reaction with water Reaction with
heated room steam
temperature
Potassiu Reacts vigorously Tarnishes Reacts vigorously Reaction too
m (K) Lilac flame when cut Floats dangerous to be
White solid Moves and fizzes attempted.
Lilac flame
Exothermic
Colourless solution
remains
Sodium Reacts vigorously Tarnishes Reacts vigorously Reaction too
(Na) Yellow/orange flame when cut Floats dangerous to be
White solid Moves and fizzes attempted.
Melts to form silvery ball
Exothermic
Colourless solution
remains
Calcium Reacts vigorously with Slowly forms Reacts readily Reaction too
(Ca) strong heat surface Rises then sinks dangerous to be
Brick red flame oxide Moves and fizzes attempted.
White solid Grey solid disappears
Exothermic
Solution becomes milky
Magnesiu Reacts readily with strong Slowly forms Very slow reaction
Reacts with strong
m (Mg) heat surface Some bubbles of gas heat
White light oxide White light
White solid White solid
Aluminiu Reacts readily with strong Slowly forms No reaction Reacts as powder
m (Al) heat as a powder surface on strong heat
White solid oxide White solid
Zinc (Zn) Reacts steadily Slowly forms No reaction Reacts as powder
Yellow solid changes to white surface on strong heat
on cooling oxide Yellow solid
changes to white
on cooling
Iron (Fe) Reacts readily as filings Slowly forms No reaction Reacts as powder
Orange sparks surface on very strong
Black solid oxide heat
Metal + Oxygen Metal Metal + Steam Metal Oxide Black+solid
Oxide Black solid
Copper Slowly formsHydrogen
No reaction No reaction
2Mg(s) + O2(g) 2MgO(s)
(Cu) surface Mg(s) + H2O(g) MgO(s) + H2(g)
Metal + Water Metal Hydroxide +
Hydrogen
Mg(s) + 2H2O(l) Mg(OH)2(s) + H2(g)
The higher up a metal, the greater the tendency
to form cations (positive ions). More reactive
metals lose electrons more easily as there are
fewer electrons on the outer shell.
Displacement reactions in solutions
More reactive metals displace less reactive metals from their
compound.
e.g. magnesium is more reactive than copper, therefore it
displaces copper from copper (II) sulphate solution:
magnesium + copper (II) sulphate → magnesium
sulphate + copper Working out a reactivity series
, Reversible Reactions & Equilibrium
Reversible reactions are where the Irreversible reactions go to completion.
products can react to re-form the reactants. Reactants covert to products, but the products
When writing a reversible reaction, ⇌, is can’t convert back to reactants e.g. complete
used. consumption of fuel, most precipitation
Examples of reversible reactions reactions, any reaction that produces a gas.
Ammonium chloride
Ammonium chloride is a white solid. When heated it breaks down into
ammonia and hydrogen chloride. When cooled, they react together again
to form ammonium chloride.
ammonium chloride ⇌ ammonia + hydrogen chloride
NH4Cl(s) ⇌ NH3(g) + HCl(g)
Copper (II) sulphate
Blue copper (II) sulphate is hydrated.
Copper (II) ions are surrounded by water molecules.
When heated, water is driven off, leaving white anhydrous copper (II)
sulphate:
e.g. 1
hydrated copper (II) sulphate ⇌ anhydrous copper (II) sulphate + water
magnesium + oxygen
magnesium oxide
Dynamic equilibrium is what is achieved when a reversible reaction happens in a closed system.
Closed system: No substances can get in or out
Open system: Substances can enter and exit 2Mg + O2 2MgO
At equilibrium: Mg gains O; gain of O is oxidation.
o forward and backward reactions continue
o rates of forward and backward reactions are the sameMg Mg2+ +2e-
Redox, Rusting
o concentrations and Iron
of reactants Mg loses 2 e-; loss of e- is oxidation.
and products remain constant
e.g. 2
Equilibrium can only be achieved if none of the reactants or products can escape.
Oxyg Hydrog Electro copper (II) oxide + hydrogen
en en ns copper + water
Oxidati Gains Loses Loses
CuO + H2 Cu + H2O
on
Rust is hydrated iron (III) oxide. It is an oxidation Cu loses O; loss of O is reduction.
reaction occurring when iron reacts with water and air:
iron + water + oxygen → hydrated iron (III) oxide Cu2+ +2e- Cu
Cu gains 2 e-; gain of e- is reduction.
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