obtaining and using metals

• What can be deduced from the reactions of metals with water, acids, and salt solutions?

  The relative reactivity of some metals
• What do the most reactive metals produce when they react with cold water?

  A metal hydroxide and hydrogen gas
• What is the reaction equation for potassium with water?

  2K + 2H₂O → 2KOH + H₂
• Which metals are classified as fairly reactive?

  Metals that react with acids
• What do almost all metals react with?

  Oxygen
• Which metal does not react with water, acids, or oxygen?

  Gold
• How can you deduce the relative reactivity of metals?

  By observing their reactions with water, acids, and oxygen
• What indicates that a reaction has taken place when metals react?

  Presence of bubbles from hydrogen production
• How can you compare the reactivity of two metals?

  Using displacement reactions
• What happens to a more reactive metal in a displacement reaction?

  It gradually disappears forming a solution
• What do less reactive metals do in displacement reactions?

  They coat the surface of the more reactive metal
• What is the definition of oxidation in terms of electrons?

  Loss of electrons
• What happens to more reactive metals during displacement reactions?

  They are oxidized by losing electrons
• What do less reactive metals do during displacement reactions?

  They are reduced by gaining electrons
• What is the reactivity series of metals?

  Order of metals based on their reactivity
• What is the relationship between a metal's reactivity and its tendency to form positive ions?

  More reactive metals form positive ions easily
• Which metals can be arranged in the reactivity series?

  Potassium, sodium, calcium, magnesium, zinc, iron, copper
• What can a more reactive metal do to a less reactive metal?

  Displace it from a compound
• Where are most metals found in the Earth's crust?

  As compounds in ores
• Why is gold found unreacted in the Earth's crust?

  Because it is very unreactive
• What do most metals require for extraction from ores?

  Chemical reactions
• How can oxidation be described in terms of oxygen?

  As the gain of oxygen
• How can reduction be described in terms of oxygen?

  As the loss of oxygen
• What is involved in the extraction of metals from ores?

  Reduction of ores
• How can metals less reactive than carbon be extracted?

  By reduction with carbon
• What does reduction involve in the context of metal extraction?

  Loss of oxygen from the ore
• What determines the method used to extract a metal from its ore?

  Its position in the reactivity series
• What is the cost implication of using electrolysis for metal extraction?

  It is expensive due to high energy use
• What happens to iron oxide during extraction with carbon?

  It loses oxygen and is reduced
• What does carbon do during the reduction of iron oxide?

  It gains oxygen and is oxidized
• What is the process illustrated for metal extraction?

  Heating with carbon and electrolysis
• When can metals be extracted by reduction with carbon?

  If the metal is less reactive than carbon
• What method is used for extracting metals more reactive than carbon?

  Electrolysis
• Why is electrolysis considered expensive for metal extraction?

  It requires large amounts of energy
• What is the chemical equation for the reduction of iron oxide with carbon?


  2Fe₂O₃(s) + 3C(s) -> 4Fe(l) + 3CO₂(g)
• At what temperatures is iron extraction carried out?

  At high temperatures in a blast furnace
• How are metals more reactive than carbon extracted?

  By electrolysis of molten compounds
• What is used as the positive electrode in aluminium extraction?

  Carbon
• What is phytoextraction?

  Plants absorb metal compounds through roots
• What do plants do with absorbed metal compounds in phytoextraction?

  Concentrate them into shoots and leaves