Chemistry 2 Unit 5

Card Set Information

Chemistry 2 Unit 5
2013-05-11 14:09:16

Salts and Electrolysis
Show Answers:

  1. What are the state symbols and what do they represent?
    • S = solid
    • l = liquid
    • g = gas
    • aq = aqueous solution
  2. Whats the pH of Acids?
    • Strong acids = 0-3
    • Weak acids = 4-6
  3. What's the pH of alkaline?
    • Weak alkaline = 8-11
    • Strong alkaline = 12-14
  4. What are the products of reacting acids with metals?
  5. What are the products of reacting acids with alkalines/ bases (metal oxides/hydroxides)?
  6. What is the function of precipitation?
    Precipitation is used to remove unwanted ions from solutions
  7. How is ammonium salts produced and what are they used for?
    • Ammonium salts are produced by reacting ammonia with acids or dissolving in water.
    • Ammoni salts are used as fertilisers
  8. What is electrolysis?
    This is the process that issues electricity to breakdown compounds into elements
  9. What occurs during electrolysis?
    During electrolysis the positively charged ions move to the negative electrode forming metals or hydrogen and the negatively charged ions move to the positive electrodes forming non-metals
  10. What is meant by reduction?
    At the negatively charged electrode, positively charged ions gain electrons
  11. What is meant by oxidation?
    At the positively charged electrode, negatively charged ions lose electrons
  12. What is the half equation of lead bromide?
    • Neg: Pb2+ ➕ 2e- ➡ Pb
    • Pos: 2Br- ➡ Br2 ➕ 2e-
  13. What must be done to aluminium oxide before it can be electrolysed?
    Aluminium oxide must be purified and melted to be electrolysed
  14. How is aluminium extracted from aluminium oxide?
    • Aluminium is obtained from aluminium oxide by electrolysis
    • Aluminium ions are reduced to aluminium atoms at the negative electrode by gaining electrons
    • Oxygen ions are oxidised to oxygen atoms at the positive electrode by losing electrons
  15. What is the equation for the electrolysis of aluminium oxide?
    Aluminium oxide ➡ aluminium + oxygen
  16. What is the half equation of aluminium oxide?
    • Neg: Al3+ ➕ 3e- ➡ Al
    • Pos: 2O2- ➡ 2O2 ➕ 4e-
  17. Why's is carbon dioxide produced in the electrolysis of aluminium oxide?
    The positive electrode is made of carbon, which reacts with the oxygen to produce carbon dioxide
  18. Why is cryolite used?
    • Cryolite is used to lower the operating temperature of the electrolysis cell to enable the electrolysis of aluminium oxide
    • To save energy
  19. What is brine?
    Brine is a solution of sodium chloride in water
  20. What does the electrolysis of brine produce?
    • The electrolysis of brine produces hydrogen and chlorine
    • Sodium hydroxide solution is also produced
  21. What is the half equation of brine?
    • Neg: 2Cl- ➡ Cl2 ➕ 2e-
    • Pos: 2H+ ➕ 2e- ➡ H2
  22. What can sodium hydroxide be used for?
    Soap, bleach, neutralising acids
  23. What is electroplating used for?
    • Make objects look more attracting
    • Protect metal objects from corroding
    • Increase hardness of surface
    • Reduce costs by using thin layers that pure metal