reactions of metals

• What happens at the cathode during electrolysis of aluminium oxide?

  Aluminium ions gain electrons and form aluminium atoms
• What occurs at the anode during the electrolysis of aluminium oxide?

  Oxide ions lose electrons and form oxygen gas
• What is the result of the reaction between oxygen and carbon anodes during electrolysis?

  The oxygen reacts with the carbon anodes, forming carbon dioxide
• Why must the carbon anodes be replaced frequently during aluminium production?

  They are gradually oxidised during the process
• Write the half equation for the oxidation of oxide ions during the electrolysis of aluminium oxide.

  2O²⁻ → O₂ + 4e⁻
• What does the half equation for oxide ions indicate about the process of oxidation?

  Oxidation is the loss of electrons
• How are aluminium ions reduced during the electrolysis of aluminium oxide?

  Aluminium ions gain electrons to form aluminium atoms
• What is the purpose of cryolite in the electrolysis process of aluminium extraction?

  Cryolite lowers the melting point of aluminium oxide
• Why is aluminium more expensive than iron despite being more abundant in the Earth's crust?

  Because of the large amounts of electrical energy used in the extraction process
• What is the state of aluminium oxide when used as an electrolyte in electrolysis?

  It must be molten to act as an electrolyte
• What happens to the energy costs when aluminium oxide is dissolved in molten cryolite?

  It reduces the energy costs of melting aluminium oxide
• What is the chemical equation for the reduction of iron(III) oxide by carbon?

  Fe₂O₃(s) + 3C(s) → 2Fe(l) + 3CO(g)
• Why can carbon be used to extract iron from iron(III) oxide?

  Because carbon is more reactive than iron
• What is the general principle behind the extraction methods used for different metals?

  The extraction method depends on the metal's position in the reactivity series
• What happens to copper oxide when heated with carbon?

  Copper oxide is reduced to copper
• What is the balanced equation for the reduction of copper oxide by carbon?

  2CuO(s) + C(s) → 2Cu(l) + CO₂(g)
• What is the definition of an ore?

  An ore is a rock that contains enough of a metal or a metal compound to make extraction worthwhile
• What is the significance of the reactivity series in metal extraction?

  It helps determine the method of extraction for different metals
• What is the relationship between oxidation and reduction in redox reactions?

  Oxidation is the loss of electrons, while reduction is the gain of electrons
• What does the acronym OIL RIG stand for in chemistry?

  Oxidation Is Loss, Reduction Is Gain
• What are the methods of extracting metals based on their reactivity?

  • Electrolysis for most reactive metals (e.g., potassium, sodium, lithium)
  • Heating with carbon for less reactive metals (e.g., zinc, iron, copper)
  • Unreactive metals (e.g., gold) found as elements
• What are the steps involved in the electrolysis of aluminium oxide?

  1. Aluminium ore is treated to produce pure aluminium oxide.
  2. Aluminium oxide is dissolved in molten cryolite.
  3. Electrolysis occurs, with aluminium ions gaining electrons at the cathode and oxide ions losing electrons at the anode.
  4. Oxygen reacts with carbon anodes, forming carbon dioxide.
  5. Anodes are gradually oxidised and need replacement.
• What are the key points about the extraction of iron using carbon?

  • Iron(III) oxide is reduced to molten iron.
  • The reaction produces carbon monoxide.
  • Carbon displaces iron from iron compounds due to its higher reactivity.
  • This method is cheaper than electrolysis.
• What is the significance of displacement reactions in the context of metal extraction?

  • Displacement reactions demonstrate redox processes.
  • More reactive metals can displace less reactive metals from their compounds.
  • They are used to deduce a reactivity series.
• What is the role of half equations in electrolysis and redox reactions?

  • Half equations show the oxidation and reduction processes separately.
  • They clarify the transfer of electrons during reactions.
  • They help in understanding the overall redox reaction.
• How can a reactivity series be deduced through displacement reactions?

  • By testing different metals in salt solutions.
  • Observing which metals displace others.
  • Ranking metals based on their ability to displace others from compounds.
• What happens to metal atoms when they react with other substances?

  They lose electrons to form positive ions.
• What does the reactivity series of metals show?

  It shows metals in order of decreasing reactivity.
• What are the general characteristics of more reactive metals?

  • More vigorous reactions
  • More easily lose electrons to form positive ions (cations)
• Which metal is the most reactive according to the reactivity series?

  Potassium
• What is the reaction of sodium with cold water?

  It reacts violently.
• How does magnesium react with dilute acids?

  It reacts rapidly.
• What is formed when a metal reacts with water?

  A metal hydroxide and hydrogen are formed.
• Write the balanced equation for the reaction of sodium with water.

  $2Na(s) +$$2H_2O(l) \rightarrow 2NaOH(aq) +$$H_2(g)$
• What happens when a metal reacts with a dilute acid?

  A salt and hydrogen are formed.
• Write the balanced equation for the reaction of magnesium with hydrochloric acid.

  $Mg(s) +$$2HCl(aq) \rightarrow MgCl_2(aq) +$$H_2(g)$
• What is the general trend of reactivity in metals when reacting with dilute acids?

  The more reactive the metal, the more rapid the reaction is.
• What is the result of a metal below hydrogen in the reactivity series when reacting with dilute acids?

  It will not react with dilute acids.
• What can be predicted about platinum's reaction with dilute acids based on its position in the reactivity series?

  It will not react with dilute acids.
• What do many metals form when they react with oxygen?

  Metal oxides.