Single Displacement Reactions

SCH 3U Single Displacement Reactions Purpose: To develop the activity series of metals through reactions of metals with ionic solutions.

Hypothesis:

***Active metals give up their electrons to ions of more stable (and less reactive) metals.*** Use the activity series, to predict the products of the following reactions. If no reaction is expected, enter NR.

Elemental Metal Metal ion New elemental New metal ion (solid) (solution) metal or gas

Mg Fe(NO3)3

Fe CuCl2

Zn MgCl2

Mg AgNO3

Fe ZnCl2 Zn HCl

Materials:

Spot plate bottle of distilled water

Metals Solutions Mg(ribbon) Zn (strip) Fe(NO3)3 (aq) MgCl2(aq) HCl(aq) Fe (iron wool) Cu (wire) CuCl2(aq) ZnCl2(aq) AgNO3 (aq)

Procedure: Wear goggles at all times. Review precautions for handling acids. Since silver nitrate may stain skin and clothing, avoid contact. Dispose of solutions in the beaker marked as waste disposal.

1. Obtain a spot plate. In each of six (6) wells put a small piece of magnesium ribbon. Add 5 mL of each reagent according to the instructions below. Observe the metal in each of the reagents for a few minutes. Record your observations. Wait approximately 10 minutes (during this time you can start working on the questions) noting any changes during this period. Try to rank the reactions with respect to the rate at which they occur. Be descriptive! 2. Discard the contents of the spot plate in the waste beaker, making sure to return any unreacted metal.

Well1: distilled water Well 4: CuCl2(aq)

Well 2: Fe(NO3)3 (aq) Well 5: MgCl2(aq),

Well 3: ZnCl2(aq) Well 6: AgNO3 (aq)

Well 7: HCl(aq) ***use 5 drops instead of 5 mL*** 3. Repeat steps one and two using each of the following metals: copper, iron, and zinc. Observations:

Title: ______

3+ 2+ 2+ 2+ + + Metal/ Distilled water Fe Fe(NO3)3) Zn (ZnCl2) Cu (CuCl2) Mg (MgCl2) Ag AgNO3 H (HCl) Solution H2O

Magnesium Mg2+

Copper Cu2+

Iron Fe3+

Zinc Zn2+ Analysis: 1. Which metal reacted with the most solutions? 2. Which metal reacted with the fewest solutions? 3. List the metals in order of their reactivity, starting with the most reactive metal. (The most reactive metal is the one that reacted with the most solutions, while the least reactive metal is the one that reacted with the fewest solutions). Such a ranking of elements is called an activity series. 4. Based on your activity series, explain why it was decided to make the Statue of Liberty with copper instead of zinc. 5. Based on your activity series, which material might have been a better choice than copper for the Statue of Liberty? Why do you think it wasn’t chosen? 6. Given your knowledge of relative chemical activity among these metals, a. Which metal is most likely to be found in an uncombined or “free” state in nature? b. Which metal would be least likely to be found uncombined with other elements? 7. Devise an experiment to investigate if Au is more reactive than Cu. Be specific. Use formulas in your answer. 8. Group 1A metals are more reactive than group 2A metals. Hence, you might suspect that elements become less reactive as atomic number increases in a period on the periodic table. Do the transition metals you studied in this experiment support this assumption? Be specific!

Conclusion: Write a brief summary stating your results i.e. write word and balanced chemical equations for each of the reactions, including the ones with NO REACTION. Be sure to include, states of matter, compare these equations to your original predictions. Suggest two improvements to the lab equipment or procedural steps that would improve the results.

Formal Lab write up is expected; Title page, Purpose, Intro (just your predictions –chemical equations), materials, procedure as per usual, observations re-type or attach if neat, within the appendix, analysis (questions), and conclusion see above.

Applications The situation is not entirely straight forward as explained at this level of your studies. The ions formed by certain metals have electron configurations which allow greater stability (multi-valences) in the presence of another metal. This is the basis for electrochemistry and the production of devices such as batteries (lead storage battery (cars), zinc-cadmium, alkaline batteries and others). They are also called electron transfer reactions or redox (reduction and oxidation ) reactions. It is relatively easy to see that the reaction takes place between a metal and in ion by writing the net ionic equation.