types of chemical reactions

• what is an acid

  a substance that releases H+ ions when dissolved in water
• what is an alkali

  a soluble base
• what is a base

  a substance that neutralises acids
• Complete the general equation: Acid + Alkali ->

  Acid + Alkali -> salt + water
• Complete the general equation: Acid + Metal ->

  Acid + Metal -> salt + hydrogen
• Complete the general equation: Acid + metal oxide (base) ->

  Acid + Metal Oxide (base) -> salt + water
• Complete the general equation: Acid + Carbonate ->

  Acid + Carbonate -> salt + water + carbon dioxide
• what is a pH

  measure of how acidic or alkaline a substance is
• Complete the pH scale

  A = acid

  B = neutral

  C = alkali

  
• if there are more H+ ions than OH- ions then the substance is acidic and if there are more OH- ions than H+ ions then the substance is alkaline
• name 2 ways of measuring the pH of a solution

  • universal indicator
  • pH metre (probe)
• what is neutralisation

  the reaction between an acid and a base (or an alkaili) to form a salt and water
• what is a dilute acid

  an acid that contains a low ratio of acid : volume of solution
• what is a concentrated acid

  an acid that contains a high ratio of acid : volume of solution
• what is a strong acid and give an example

  an acid that is fully ionised (in an aqueous solution)

  e.g hydrochloric acid
• what is a weak acid and give an example

  an acid which is partially ionised (in an aqueous solution)

  e.g ethanoic acid
• give 3 features of a strong acid

  • fully ionised
  • high concentration of H+ ions
  • faster rate of reaction
• give 3 features of a weak acid

  • partially ionised
  • low concentration of H+ ions
  • slower rate of reaction
• as the pH increases by 1, the concentration of H+ ions decreases by a factor of 10
• what can be used to show the effect on pH of changing the concentration of H+ ions during neutralisation

  a pH titration curve