Single Displacement Reactions

1. Single Displacement Reactions

2. Learning Goals Students will be able to: • Identify single displacement reactions • Predict products for and balance single displacement reactions • Determine which single displacement reactions actually occur

3. Success Criteria • Students will be able to: • Use the A + BC ⇒ B + AC symbolic formula to identify a single displacement reaction and to determine products. • Use the Activity Charts to determine which single displacement reactions will proceed forward

4. Activity Observe the following reaction: • Copper + silver nitrate  • What do you observe? • What is the precipitate? • What do you notice about the solution? • Write a complete, balanced equation for this reaction. • Cu + AgNO3 Ag + Cu(NO3)2

5. Single Displacement Reaction • Is a reaction in which one element takes the place of another element in a compound • The products of a single displacement reaction are a new element and a new compound. • Single Displacement reactions occur between ionic compounds

6. Types of Single Displacement Reactions • A metal displacing another metal from an ionic compound • A and B represent metals, C is a non-metal C + C B  + B A A

7. Types of Single Displacement Reactions • A non-metal displacing another non-metal from an ionic compound • A represents a metal, B and C non-metals C B + C B  + A A

8. Dancing Analogy • Single displacement is similar to one man cutting in on another man at the dance At the start, dancer A is by himself and dancer B is dancing with dancer C. Dancer A “cuts in” on dancer B. In the end, dancer B is by himself and dancer A is dancing with dancer C

9. Writing the Reaction • Magnesium metal + lead (II) nitrate solution • List your observations • Write a chemical equation

10. Now try these ones! • zinc + lead (II) nitrate  • Zn + Pb(NO3)2 Pb + Zn(NO3)2 • copper (II) nitrate + magnesium  • Cu(NO3)2 + Mg  Mg(NO3)2+ Cu • *Lead + copper (II)nitrate  • Pb + Cu(NO3)2 Cu + Pb(NO3)2(Pb2+ is more common) • *Iron + sulfuric acid  • Fe + H2SO4 H2+ Fe2(SO4)3(Fe3+ is more common) • *remember to use the correct ion for multivalent metals. Your periodic table will tell you which is the more common “oxidation state”. • Find these metals and solutions and watch them react!

11. How do we determine which elements can displace another? • Empirical evidence gathered through experimentation Figure 1: (a) In the activity series of metals, each metal will displace the metal listed below it. Hydrogen is usually included in the series, even though it is not a metal, because hydrogen can form positive ions, just like the metal (b) The halogens can also be ordered in an activity series (Nelson Chemistry 11 – p.126 Figure 3 and p. 127 Figure 4)

12. Yesterday, you were given a more detailed activity series.

13. For a reaction to occur, the element replacing the element within a compound MUST be more reactive • The lower the electronegativity of a metal element the more reactive it should be. We notice that the opposite is true for the halogens(higher electronegativity = more reactive). WHY?? Example 1: 2 Al(s) + Fe2O3(s)  Example 2: Zn(s) + Mg(NO3)2(aq)  2 Fe(s) + Al2O3(s) NO REACTION

14. Is gold reactive??

15. Which reaction will move forward? 1) aluminum + copper (II) nitrate ⇒ • Aluminum is higher on the activity series than copper, therefore a reaction takes place • 2 Al + 3 Cu(NO3)2 ⇒ 3 Cu + 2 Al(NO3)3 • We should see a coating of copper on the aluminum and the solution should turn from blue to colourless 2) iron + aluminum nitrate ⇒ • Iron is lower on the activity series than aluminum, therefore no reaction takes place • Fe + Al(NO3)3⇒ NR • The piece of iron should remain unaffected by the solution

16. Which reaction will move forward? 3) magnesium + hydrochloric acid ⇒ • Magnesium is higher on the activity series than copper, therefore a reaction takes place. • Mg + 2HCl ⇒ H2+ MgCl2 • We should see bubbles of gas as hydrogen gas is produced and the strip of magnesium slowly consumed. The solution remains colourless. 4) copper + hydrochloric acid ⇒ • copper is lower on the activity series than hydrogen, therefore no reaction takes place. • Cu + HCl⇒ NR • The piece of copper should remain unaffected by the acid

17. Which reaction will move forward? 5) tin + nickel (II) sulfate • tin is lower on the activity series than nickel, therefore no reaction takes place. • Sn+ NiSO4⇒ NR • The piece of tin should remain unaffected by the solution. 6) magnesium + iron (III) chloride • magnesium is higher on the activity series than iron, therefore a reaction takes place. • 3 Mg + 2FeCl3⇒ 2 Fe + 3 MgCl2 • We should see iron precipitate onto the magnesium. The solution should change from reddish-brown to colourless.

18. Non-metals switching • A + BC ⇒ C + BA • Does a reaction occur? • Use the Non Metal (Halogen) Activity Chart • If so, predict the products. Balance the equation if necessary. Br2(aq) + NaI(aq) 

19. Corrosion and Protection • Can protect against corrosion by coating iron in a less reactive metal (example copper) • The statue of liberty was made out of iron, covered with insulation, and then coated with copper • Over time, the copper oxidized and the insulation wore away in places. • The more reactive iron then rusted when it came into contact with the copper (II) oxide. WHY?? The iron had to be replaced with stainless steel.

20. The Galvanizing Process A more reactive metal (zinc) is used to coat the iron. The zinc quickly reacts with oxygen to form zinc oxide (hard and insoluble). The zinc acts as a barrier to protect the iron underneath.

21. Galvanized Steel • Much of the world’s steel is galvanized for rust protection. • Stainless steel contains a significant portion of nickel and chromium

22. Boats – Sacrificial Anode • Water, especially salt-water, will corrode boat hulls. • So boaters place a strip of a more active metal on the surface of the boat – as a result the strip will corrode first and protect the rest of the hull • The strip is called a sacrificial anode because it is sacrificed in defense of the rest of the hull

23. Mining • Metals are often removed from rock by using strong acid solutions. • Rocks are crushed into a fine slurry and added to tanks of acid. • The acids dissolve the metals from minerals and rocks. • The acids eventually transform into metal-rich solutions • How could you remove the metals from these solutions? (Hint: think about what you know about the activity series)

24. Removing copper from copper ore • Sheets of a metal higher on the activity series than Cu are placed in the copper solution. An electrical current speeds up the procedure Copper solution Sheets of copper

25. Review • A single displacement reaction is a reaction where one element takes the place of another element in a compound. • Use the activity series to determine if a reaction will occur.

26. Practice • Complete the worksheet: Single Displacement Reactions Practice • Answer #1, 3, 5, 6 on pg. 128 of the textbook.