Chemistry MUST MEMORISE

Equation for reaction of sodium oxide and water

Na2O(s) + H2O(l) → 2NaOH(aq)

pH of solution for reaction of sodium oxide and water

pH 13

Equation for reaction of magnesium oxide and water

MgO(s) + H2O(l) ←/→ Mg(OH)2(aq)

Dissolution is reversible where small amount of MgO reacts with water

Because MgO highly exothermic lattice energy

pH of solution for reaction of magnesium oxide and water

pH 9

Equation for reaction of aluminium oxide and water

Don’t have

Insoluble

Because Al2O3 highly exothermic lattice → strong ionic bonds w covalent character

pH of solution for reaction of aluminium oxide and water

pH 7

Equation of reaction of silicon oxide and water

Don’t have

Insoluble

Because numerous strong covalent bonds between atoms

pH of solution for reaction of aluminium oxide and water

pH 7

Equation for reaction of phosphorus oxide and water

P4O10(s) + 6H2O → 4H3PO4(aq)

pH of solution for reaction of phosphorus oxide and water

pH 2

Equation for reaction of sulfur oxide and water

SO3(g) + H2O(l) → H2SO4(aq)

pH of solution for reaction of sulfur oxide and water

pH 2

Equation for reaction of sodium oxide and acid

Na2O(s) + 2HCl(aq) → 2NaCl(aq) + H2O(l)

Equation for reaction of sodium hydroxide and acid

NaOH(aq) + HCl(aq) → NaCl(aq) + H2O(l)

Equation for reaction of aluminium oxide and acid

Al2O3(s) + 6HCl(aq) → 2AlCl3(aq) + 3H2O(l)

Equation for reaction of aluminium oxide and alkalis

Al2O3(s) + NaOH(aq) + 3H2O(l) → 2NaAl(OH)4(aq) [sodium aluminate]

Equation for reaction of aluminium hydroxide and acid

Al(OH)3(s) + 3HCl(aq) → AlCl3(aq) + 3H2O(l)

Equation for reaction of aluminium hydroxide and alkalis

Al(OH)3(s) + NaOH(aq) → NaAl(OH)4(aq) [sodium aluminate]

Equation of reaction of silicon oxide and alkalis

SiO2(s) + 2NaOH(conc.) → Na2SiO3(aq) [sodium silicate] + H2O(l)

Must be hot concentrated alkali

Equation for reaction of phosphorus oxide and alkalis

P4O10(s) + 12NaOH(aq) → 4Na3PO4(aq) + 6H2O(l)

Equation for reaction of sulfur oxide and alkalis

SO3(g) + 2NaOH(aq) → Na2SO4(aq) + H2O(l)

Equation for reaction of sodium chloride and water

NaCl(s) → Na^+(aq) + Cl^-(aq)

Without hydrolysis

pH of solution for reaction of sodium chloride and water

pH 7

Equation of reaction of magnesium chloride and water

MgCl2(s) + 6H2O(l) → [Mg(H2O)6]²^+(aq) + 2Cl^-(aq)

Appreciable hydrolysis

[Mg(H2O)6]²^+(aq) + H2O(l) ←/→ [Mg(H2O)5(OH)]^+(aq) + H3O^+(aq)

pH of solution for reaction of magnesium chloride and water

pH 6.5

Equation for reaction of aluminium chloride and water

AlCl3(s) + 6H2O(l) → [Al(H2O)6]³^+(aq) + 3Cl^-(aq)

Appreciable hydrolysis

[Al(H2O)6]³^+(aq) + H2O(l) ←/→ [Al(H2O)5(OH)]²^+(aq) + H3O^+(aq)

pH of solution for reaction of aluminium chloride and water

pH 3

Equation of reaction of silicon chloride and water

SiCl4(l) + 2H2O(l) → SiO2(s) + 4HCl(aq)

Complete hydrolysis

pH of solution for reaction of silicon chloride and water

pH 2

Equation of reaction of phosphorus chloride and water

PCl5(s) + 4H2O(l) → H3PO4(aq) + 5HCl(aq)

Complete hydrolysis

pH of solution for reaction of phosphorus chloride and water

pH 2

Complex ion for Al³^+

[Al(OH)4]^-

Equilibrium equation for Al³^+ and its complex ion

Al³^+(aq) + 4OH^-(aq) ←/→ [Al(OH)4]^-(aq)

Complex ion for Ag^+

[Ag(NH3)2]^+

Equilibrium equation for Ag^+ and its complex ion

Ag^+(aq) + 2NH3(aq) ←/→ [Ag(NH3)2]^+(aq)

Complex ion of Cu²^+

[Cu(NH3)4(H2O)2]²^+

Equilibrium equation for Cu²^+ and its complex ion

Cu²^+(aq) + 4NH3(aq) + 2H2O(aq) ←/→ [Cu(NH3)4(H2O)2]²^+(aq)

Complex ion of Cr³^+

[Cr(OH)6]³^-

Equilibrium equation for Cr³^+ and its complex ion

Cr³^+(aq) + 6OH^-(aq) ←/→ [Cr(OH)6]³^-(aq)

Complex ion of Zn²^+

[Zn(OH)4]²^-

[Zn(NH3)4]²^+

Equilibrium equation of Zn²^+ and its complex ions

Zn²^+(aq) + 4OH^-(aq) ←/→ [Zn(OH)4]²^-(aq)

Zn²^+(aq) + 4NH3(aq) ←/→ [Zn(NH3)4]²^+(aq)

Colour of Cr³^+(aq)

Green

Colour of Cr(OH)3(s)

Grey-green

Colour of [Cr(OH)6]³^-(aq)

Dark green

Colour of CrO4²^-(aq)

Yellow

Colour of Cr2O7²^-(aq)

Orange

Colour of Mn²^+(aq)

Pale pink

Colour of MnO2(s)

Black/brown

Colour of MnO4²^-(aq)

Green

Colour of MnO4^-(aq)

Purple

Colour of Fe²^+(aq)

Green

Colour of Fe³^+(aq)

Yellow

Colour of Fe(OH)2(s)

Dirty-green

Colour of Fe(OH)3(s)

Red-brown

Colour of [Fe(SCN)(H2O)5]²^+(aq)

Blood-red

Colour of Cu2O(s)

Red-brown

Colour of CuI(s), CuCl(s)

White

Colour of Cu²^+(aq)

Blue

Colour of Cu(OH)2(s)

Pale blue

Colour of [CuCl4]²^-(aq)

Yellow

Colour of [Cu(NH3)4(H2O)2]²^+(aq)

Dark blue

Colour of CuCO3(s)

Blue-green

Tollen’s reagent

[Ag(NH3)2]^+

Fehling’s solution

Cu²^+

Equation with Tollen’s reagent

RCHO + 2[Ag(NH3)]^+ + 3OH^- → RCOO^- + 2Ag + 4NH3 + 2H2O

Equation with Fehling’s solution

RCHO + 2Cu^+ + 5OH^- → RCOO^- + Cu2O + 3H2O

Equation of iodoform test on -CH(CH3)OH

RCH(CH3)OH + 6NaOH + 4I2 → CHI3 + RCO^-Na^+ + 5NaI + 5H2O

Equation of iodoform test on -COCH3

RCOCH3 + 4NaOH + 3I2 → CHI3 + RCO2^-Na^+ + 3NaI + 3H2O