chemistry

• what is oxidation?


  Loss of electrons.
• what is reduction?


  the gaining of electrons
• what is the reactivity series?

  The reactivity series is a list of metals arranged in order of their reactivity, with the most reactive metal at the top and the least reactive metal at the bottom.
• what are the trends of reactivities of metals in reactions with acid/water?

  metals above H2 react with acid , more reactive metal, quicker and violent.
• what is a displacement reaction?

  where a more reactive metal takes over a less reactive metal
• how are unreactive metals found in the earth?

  in their natural state so minerals or ores
• how can metals less reactive then carbon be extracted?

  reduction with carbon, carbon displaces metal in a metal oxide. Metal reduces to pure metal
• how can metals more reactive then carbon be extracted?

  Electrolysis
• what is the general equation for a reaction between metals and acids?

  Metal + Acid -> Salt + Hydrogen gas
• what reaction is metal plus acid?

  displacement
• which metals in the reactivity series will react with acid?

  Metals above hydrogen in the reactivity series will react with acids.
• what is the general equation for neutralisation?

  Acid + Base -> Salt + Water
• what is the general equation for a reaction between metal carbonate + acid?

  metal carbonate + acid = salt + water+ carbon dioxide
• what is the general equation for the reaction between metal oxides + acid?

  metal oxide + acid = salt + water
• what is a redox reaction?

  A redox reaction is a chemical reaction that involves the transfer of electrons between species.
• how is soluble salt formed?

  1 react excess acid with some insoluble chemical (metal oxide)

  2 filter off leftover

  3 crystallise product
• what do acids and alkalis produce in aqueous solutions?

  acids = hydrogen ions

  alkalis= hydroxide ions
• what are bases?


  compound that neutralises acid
• what is an acid?


  A substance that donates hydrogen ions (H+) in a chemical reaction.
• what is an alkali?

  A base that dissolves in water.
• what is the Ph scale?

  Measure of acidity or alkalinity.
• what is Ph 7?

  Neutral so water
• what is a strong acid?

  completely ionised
• what is a weak acid?

  partially ionised
• what happens to the Ph as concerntration of hydrogen increases?

  decreases
• what is a concentrated acid?


  strong acid - more moles of acid per volume
• what is a dilute acid?

  weak acid - less moles of volume per unit
• Ph deacreases by one unit, what change is seen in hydrogen ion concerntration?

  increases by 10
• what is electrolysis?


  an ionic compound being broken down by using electricity
• what is an electrolyte?

  A substance that conducts electricity when dissolved in water or melted.
• what is a cathode?

  Negative electrode.
• what is an anode?

  Positive electrode.
• what occurs at a cathode?

  Reduction
• what occurs at an anode?

  Oxidation
• how is aluminium manufactured?

  Bauxite.
• why is the aluminium extraction expensive?

  Electricity
• what is the exothermic definition?

  energy from reacting chemical is transferred into the surrounding are and the temperature of the surrounding increases
• what is an example of an exothermic reaction?


  combustion, oxidisation and neutralisation
• what is the endothermic definition?

  energy from the surroundings is transferred to reacting chemicals, the surroundings temperature decreases
• what is an example of an endothermic reaction?

  thermal decomposition, citric acid + sodium hydrogen