chemistry acids + alkalis

pH less than 7=acid

pH more than 7=alkali

pH 7=neutral substance

lower the pH=more acidic

higher the pH=more alkaline

to test the pH use an indicator

an indicator is a dye that changes colour

when dissolved in water...

acids form hydrogen ions(H+)

alkalis form hydroxide ions(OH‾)

neutralisation reaction=

acid+alkali—>salt+water

H+(aq)+OH‾(aq)—>H₂O(i)

the solution formed in neutralisation reactions are neutral-have a pH of 7

strong acids ionise completely in water to release H+ ions

examples: HCI, H₂SO₄

weak acids ionise partially in water to release H+ ions

ionisation of a weak acid is reversible

examples: citric/carbonic acids

if the concentration of H+ ions is higher the rate of reaction is higher

strong acids are more reactive than weak acids because the particles dissociate more than weak acids

the lower the pH the higher the concentration of H+ ions-the solution is more acidic

bases are substances that react with acids in neutralisation reactions

bases are insoluble and alkalis are soluble

metal oxides and carbonates are bases

metal hydroxide is an alkali

acid+metal oxide/hydroxide—>salt+water

acid+metal carbonate—>salt+water+carbon dioxide (bubbles produced)

making salts from acids + insoluble bases

1. put acid in beaker and warm the dilute acid with bunsen burner

2. add insoluble…