Electrolysis extended content

• What is electrolysis used for?

  Breaking down electrolytes to form elements
• What can be predicted from electrolysis?

  The products of electrolysis for an electrolyte
• Name two applications of electrolysis.

  Electroplating and purifying metals
• What is electrolysis of water?

  • Decomposition of water using electric current
  • Produces hydrogen and oxygen gases
  • Reaction: $2H_2O(l) \rightarrow 2H_2(g) +$$O_2(g)$
• What does the equation $2H_2O(l) \rightarrow 2H_2(g) +$$O_2(g)$ indicate about hydrogen and oxygen in water?


  Hydrogen volume is double that of oxygen
• What occurs at the negative electrode during electrolysis of water?

  A reduction reaction occurs
• What is the reaction at the cathode during electrolysis of water?

  $4H^+$$(aq) +$$4e^- \rightarrow 2H_2(g)$
• What occurs at the positive electrode during electrolysis of water?

  An oxidation reaction occurs
• What is the reaction at the anode during electrolysis of water?

  $4OH^-(aq) \rightarrow 2H_2O(l) +$$O_2(g) +$$4e^-$
• What is the process of electrolysis of ionic solutions?

  • Involves breaking down ionic compounds
  • Uses electric current to separate ions
  • Produces elements at electrodes
• What are the key concepts of electrolysis?

  • Decomposition of compounds
  • Involves electrodes (anode and cathode)
  • Reduction and oxidation reactions occur
• What does electrolysis involve?

  Using electricity to break down electrolytes
• What can be predicted from electrolysis?

  The products of electrolysis for an electrolyte
• What are two applications of electrolysis?

  Electroplating and purifying metals
• What is electrolysis of ionic solutions?

  • Decomposition of ionic compounds using electric current
  • Involves aqueous solutions of ionic compounds
  • Can produce elements at electrodes
• What is an ionic compound?

  A compound of positive and negative ions
• What does the term 'molten' refer to?

  A liquid formed by heating a solid
• What are hydrogen ions represented as?

  H⁺
• What determines whether metal or hydrogen is produced at the negative electrode?

  The metal's position in the reactivity series
• What happens during the electrolysis of copper(II) chloride solution?

  Copper is produced at the negative electrode
• What is produced during the electrolysis of sodium chloride solution?

  Hydrogen gas and chlorine gas
• What is produced at the positive electrode during electrolysis of sodium chloride?

  Chlorine gas
• What is the reaction at the anode during electrolysis of sodium chloride?

  2Cl^- → Cl₂ + 2e^-
• What is the reaction at the cathode during electrolysis of sodium chloride?

  2H⁺ + 2e^- → H₂
• What happens to sodium and hydroxide ions during electrolysis of sodium chloride solution?

  They remain in solution
• What is formed during the electrolysis of sodium chloride solution?

  Sodium hydroxide
• How is the electrolysis of sodium chloride solution carried out industrially?

  Using sea water to produce gases and sodium hydroxide
• What are the products of electrolysis for common ionic compounds?

  • Copper(II) chloride: Copper at cathode, Chlorine at anode
  • Sodium chloride: Hydrogen at cathode, Chlorine at anode
  • Hydrochloric acid: Hydrogen at cathode, Chlorine at anode
• What is electrolysis used for?

  Breaking down electrolytes to form elements
• What can be predicted from a given electrolyte in electrolysis?

  The products of electrolysis
• What are two applications of electrolysis?

  Electroplating and purifying metals
• What is an alloy?

  • A mixture of two or more elements
  • At least one element is a metal
• Why are many pure metals too soft for use?

  They can be made harder by adding another element
• What happens when tungsten is added to pure iron?

  It forms tool steel, which is harder
• What are the properties and uses of different types of steel?

  • Mild steel:
  • Elements: Carbon and iron
  • Properties: Easy to bend and pull into wires
  • Tool steel:
  • Elements: Tungsten and iron
  • Properties: Hard, can be heated to high temperatures
  • Stainless steel:
  • Elements: Chromium and iron
  • Properties: Hard, does not rust easily
• What elements make up mild steel?

  Carbon and iron
• What is the property of tool steel?

  Hard, can be heated to high temperatures
• What elements are in stainless steel?

  Chromium and iron
• Why does an alloy often have more uses than its pure elements?

  Alloys can be made harder and more versatile
• How does the addition of elements affect the properties of pure metals?

  It can enhance hardness and durability