Extracting metals & equilibria

• What can be deduced about the relative reactivity of metals?

  It can be deduced by their reactions with water, acids, and salt solutions.
• What happens when the most reactive metals react with cold water?

  • They produce a metal hydroxide, forming an alkaline solution.
  • Hydrogen gas is released.
  • Example reaction: \(2K + 2H_2O \rightarrow 2KOH + H_2\)
• What do fairly reactive metals react with?

  They react with acids.
• What is the general reaction of metals with oxygen?

  Metals react with oxygen to form metal oxides.
• Which metal does not react with water, acids, or oxygen?

  Gold
• How can the relative reactivity of metals be deduced?

  • By observing their reactions with water (very reactive), acids (reactive), and oxygen (not very reactive).
  • Look for bubbles to indicate hydrogen production.
• How can you determine if one metal is more reactive than another?

  • By using displacement reactions.
  • A more reactive metal will displace a less reactive metal from its salt solution.
• What happens to a more reactive metal in a displacement reaction?

  It gradually disappears as it forms a solution.
• What happens to a less reactive metal in a displacement reaction?

  It coats the surface of the more reactive metal.
• How are displacement reactions classified in terms of redox reactions?

  They involve the gain or loss of electrons.
• What happens to more reactive metals during displacement reactions?

  They lose electrons and are oxidized.
• What happens to less reactive metals during displacement reactions?

  They gain electrons and are reduced.
• What is the reactivity series of metals?

  • Metals arranged by their reactivity: potassium, sodium, calcium, magnesium, aluminium, carbon, zinc, iron, hydrogen, copper, silver, gold.
  • Shows the tendency of metal atoms to form cations.
• How do metal atoms behave when they react with other substances?

  They form positive ions.
• What is the relationship between a metal's reactivity and its tendency to form positive ions?

  More reactive metals can form positive ions more easily.
• How can metals be arranged in a reactivity series?

  • Based on their reactions with water and dilute acids.
  • Non-metals like hydrogen and carbon are often included.
• What can a more reactive metal do in a displacement reaction?

  It can displace a less reactive metal from a compound.
• Where are most metals found in the Earth's crust?

  Most metals are found as compounds in ores.
• Why is gold found in the Earth's crust as the metal itself?

  Because it is very unreactive.
• What is required to extract most metals from their ores?

  Chemical reactions are required to extract the metal.
• How can oxidation and reduction be described in terms of oxygen?

  • Oxidation is the gain of oxygen.
  • Reduction is the loss of oxygen.
• What is involved in the extraction of metals from ores?

  It involves the 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?

  Reduction involves the loss of oxygen from the ores.
• Why is the method used to extract a metal related to its position in the reactivity series?

  • Less reactive metals can be extracted by reduction with carbon.
  • More reactive metals require electrolysis for extraction.
  • Cost considerations influence the choice of extraction method.
• What is the cost implication of using electrolysis for metal extraction?

  Electrolysis is expensive due to high energy requirements.
• What happens to iron oxide during extraction by heating with carbon?

  Iron oxide loses oxygen and is reduced.
• What happens to carbon during the reduction of iron oxide?

  Carbon gains oxygen and is therefore oxidized.
• What is the process of extracting metals from ores using carbon called?

  Reduction of carbon
• Under what condition can a metal be extracted by reduction of carbon?

  If the metal is less reactive than carbon
• What method is used to extract metals that are more reactive than carbon?

  Electrolysis
• Why is electrolysis considered expensive for metal extraction?

  Due to the large amounts of energy required to melt compounds and produce electrical current
• What is the chemical reaction for the reduction of iron oxide using carbon?

  2Fe₂O₃(s) + 3C(s) -> 4Fe(l) + 3CO₂(g)
• At what temperature is iron typically extracted in a blast furnace?

  At high temperatures
• Which metal is extracted by electrolysis of molten compounds?

  Aluminium
• Why can't aluminium be extracted by reduction with carbon?

  Because it is too reactive
• What is the role of cryolite in the electrolysis of aluminium?

  It is mixed with aluminium oxide to lower the melting point
• What do some bacteria do in the process of bacterial extraction?

  They absorb metal compounds
• What are leachates in the context of bacterial extraction?

  Solutions produced by bacteria that contain metal compounds
• How can scrap iron be used in bacterial extraction?

  To obtain metal from the leachate