4 ACIDS, BASES AND SALTS

the H+ ions split from the acids eg. HCl -> H+(aq) and Cl−(aq)

An acid is a substance in which its molecules dissociates in water to produce H + (aq) ions

the acid does not ionize into h+ ions and ?? ions in the absence of water

The basicity of an acid is the number of ionizable hydrogen ions that can be produced by a molecule of the acid. (dissociate)

1 molecule of the acid yields 1 H+ ion when dissociated.

1 molecule of the acid yields 2 H+ ions when dissociated.

1 molecule of the acid yields 3 H+ ions when dissociated.

A strong acid is one in which its molecules dissociate completely in water to give a high concentration of hydrogen ions (H+).

H2SO4 HNO3 HCL

A weak acid is one in which its molecules dissociate partially in water to give a low concentration of hydrogen ions (H+).

CH3COOH H2CO3

An acid solution that contains a small amount of the dissolved acid is said to be dilute.

An acid solution that contains a large amount of the dissolved acid is said to be concentrated.

pH = – lg[H+]

concentration : small amount of acid dissolved per unit volume of water. strength : whether acid dissociate completely (strong acid) or partially (weak acid).

• Acids have a sour taste • Acids dissolve in water to form solutions which conduct electricity. • Acids turn blue litmus paper –> red. • Acids react with reactive metals to form hydrogen gas and a salt.

Kangaroos normally can’t make a crocodile zesty, for some prefer hopping closely around a pond. potassium, sodium, calcium, magnesium, aluminium, carbon, zinc, iron, tin, lead, hydrogen, copper, silver, gold, platinum

Metals above hydrogen in the reactivity series react with acids to form hydrogen and salt. • Metals below carbon can be extracted from their oxide using carbon. Eg. 2ZnO + C → 2Zn + CO2 • Metals below hydrogen can be extracted from their oxide using hydrogen gas. Eg. 2CuO + H2 → 2Cu + 2H2O

**chlorides* when they are formed from hydrochloric acid; nitrates when formed from nitric acid; sulfates when formed from sulfuric acid.

A salt is the ionic compound formed when hydrogen ions from an acid are displaced by metal or ammonium ions. The anion of salt comes from an acid. The cation comes from the base HCl + NaOH → NaCl + H₂O

place the lighted splint at the mouth of the reaction test tube. If the lighted splint extinguishes with a “pop” sound, hydrgoen gas is produced

salt + hydrogen

salt + water + carbon dioxide

Bubble the gas through a test tube of limewater using a delivery tube. If a white precipitate is formed with limewater, carbon dioxide gas is produced. CO2 (g) + Ca(OH)2 (aq) → CaCO3 (s) + H2O (l)