Metal oxides and hydroxides

Acid : compound containing hydrogen that has dissociated in water to form hydrogen ions.

E.g. equation —> HCI (g) + aq -> H+ (aq) + CI- (aq)

Base : a compound that reacts with an acid to form a salt + water.

E.g. metal oxides, metal carbonates, metal hydroxides and NH3 are all bases.

—> strong bases : NaOH + KOH
—> weak bases : NH3

Alkali : a base that dissolves in water to form hydroxide ions.
It is a base dissolved in water (soluble)

E.g. equation —> NaOH (s) + aq -> Na+ (aq) + OH- (aq)

E.g. metal hydroxides + ammonia

Amphoteric : substance can act as both acid and base.

—> Property : basic

—> What is formed? alkali solutions (hydroxide) when they react with water.

Oxide ions (is a negatively charged ion/anion)

—> Why is the oxide ion strongest basic? Anion due to its small size + high charge

—> What is produced when oxides react with water and why? Produce OH- ions because these oxide ions in the metal oxides are the strongest ions that can exist in water.

—> Salt : a compound formed by an acid-base reaction where the hydrogen in the acid has been replaced by a metal (or other +) ion.

—> Sodium oxide + hydrochloric acid -> Sodium chloride and water
—> Na2O + 2HCI > 2NaCI + H2O

—> Calcium hydroxide + sulphuric acid -> Calcium sulphate and water
—> Ca(OH)2 + H2SO4 -> CaSo4 + 2H2O