Q LATTC - CHEMISTRY 51 DATE:_________________ NAME:_____________________________________________ Lab Parner(s):______________ Chemical Changes – Single displacement Reactions These reactions are the type in which an element, such as a metal, displaces another metal or hydrogen from a compound. An example will be as follow: 2 Na (s) + 2H2O (l) 2 NaOH (aq) + H2 (g) When a metal replaces another metal or hydrogen from a solution, we say that the former is MORE ACTIVE than the latter, otherwise the reverse is true. In the above example Na is more active than H because it replaces H. If a chemical reaction was not observed than Na would have been the less active one. As in the previous experiment, the above reaction will be true if you observed evidence of a chemical reaction. Evidence of the reaction would be one of more of the following: (a) A distinctive color change. (b) The formation of a precipitate (a solid formed in solution) and/or a deposit formed on the metal surface. (c) Gas formation (look for bubbles forming and coming up). (d) The evolution of heat (touch the test tube) At this time, you may still not be able to write the correct formulas of the new substance formed in these reactions. Your laboratory instructors will help you with this. Equipment: Test tube rack, medium sized test tubes, test tube holder, graduated cylinders, watch glass to carry the metal strips. Procedure: MAKE SURE THE SAFETY GLASSES ARE ON AT ALL TIMES DO NOT UNDER ANY CIRCUMSTANCES POUR A CHEMICAL BACK INTO THE ORIGINAL REAGENT BOTTLE. 1. Pour a small quantity of distilled, water in the plastic wash bottle. Use this water to rinse your test tubes. Place all the medium sized test tubes on the test tube rack, and rinse them with the distilled water. 2. To find out what volume of solution to use, measure between 2 mL to 3 mL of water using the small graduated cylinder, and pour this into one of the test tubes. Make a note of the approximate level of the water, and use about the same level of solution during the experiment. 3. Each experiment requires the adding of a small metal strip to the solution containing the compound. Some of the metal surfaces may require cleaning with sandpaper. The following list tells you which metal to add to which solution. Place the solution into the test tube, and the corresponding metal on the watch glass. GO BACK TO YOUR STATION and drop the metal into the solution, and record your observations. Observations: Predict the products or put in NR (no reaction) for each reaction. If reaction is observed, then the solid metal is more active. If no reaction is observed, then the cation in the aq solution is more active. CIRCLE THE MORE ACTIVE Element WHERE INDICATED. 1. The first experiment is strictly a demonstration and must be done by your instructor. The students must wear their safety goggles, and they must stay very far from the demonstration area. A small piece of sodium metal and water (a small volume of water in a large beaker covered by a wire gauze). Na (s) + H2O (l) + 2. Zinc metal and magnesium sulfate solution Zn (s)+ MgSO4 (aq) + 3. Zinc metal and Tin (IV) acetate solution Zn(s) + Sn(CH3COO)4 (aq) + 4. Zinc metal and 3M sulfuric acid solution Zn(s)+ H2SO4 (aq) + 5. Copper metal and 3M sulfuric acid solution Cu(s)+ H2SO4 (aq) + 6. Copper metal and silver nitrate solution Cu(s)+ AgNO3 (aq) + 7. Tin metal and cupric nitrate solution Sn (s)+ Cu(NO3)2 (aq) + 8. Tin metal and sulfuric acid solution Sn(s) + H2SO4 (aq) + The More Active? Na H The More Active? Zn Mg The More Active? Zn Sn The More Active? Zn H The More Active? Cu H The More Active? Cu Ag The More Active? Sn Cu The More Active? Sn H Conclusion: Make an activity series list for the elements used in your experiment starting with the most active first. The elements you used were H, Na, Cu, Mg, Sn, Ag, Zn. Discuss your reasoning. LATTC CHEMISTRY 51 Chemical Changes: Double Displacement (Metathesis) Reactions Name date LAB PARTNER(S) In a double-displacement reaction, two compounds exchange anions to produce two different compounds. That is, the anion of one compound exchanges places with the anion of the other compound. e.g. KCl(aq) + AgNO3(aq) ??? AgCl(s) + KNO3(aq) One can mix two solutions containing two different dissolved compounds together to form two different compounds. However, mixing any two aqueous solutions together doesn’t necessarily mean that a reaction will occur. A reaction has occurred when you observe evidence of a chemical reaction. Evidence of a reaction may be one or more of the following: (a) A distinctive color change (either in the solution or in the solid). (b) The formation of a precipitate (a solid formed in solution, or a deposit formed on a metal’s surface) (c) Gas formation (look for bubbles forming and coming up). (d) A temperature change (usually the evolution of heat (the test tube becomes warm). (e) The breakdown of a solid. Materials and Reagents Test tube rack, medium sized test tubes, test tube holder, graduated cylinders Safety Precautions a) MAKE SURE YOU ARE WEARING PROPER SHOES, LAB COAT, & SAFETY GOGGLES AT ALL TIMES. DO NOT POUR A CHEMICAL BACK INTO ITS ORIGINAL REAGENT BOTTLE. b) Concentrated hydrochloric acid (HCl), nitric acid (HNO3), sulfuric acid (H2SO4), sodium hydroxide (NaOH), and ammonium hydroxide (NH4OH) are very hazardous in case of skin contact (corrosive, irritant, permeator), of eye contact (irritant), of ingestion. Handle these chemicals with great care. They are oxidizers, corrosive and highly toxic. c) Make sure your test tubes are held securely in your test tube rack. Hold your test tube rack with both hands to minimize the chances of an accident occurring. PROCEDURE l. Place test tubes in a test tube rack. Clean and rinse all of the test tubes with distilled water. [Fill a plastic wash bottle with distilled water. Use the distilled water as a final rinse for your test tubes.] 2. Each experiment requires mixing two solutions together. The next page gives the two solutions to mix (i.e. add to each test tube). Take two clean test tubes and add about 1 mL of the solution shown to each test tube. Return to your lab bench and mix (pour the contents of one of the test tubes into the other test tube, and swirl the contents of the test tube to mix). 3. If a reaction occurs, give the evidence. Then complete and balance the chemical equation. If no reaction occurs, write NR (no reaction) on the product side of the chemical equation. 4. Repeat steps #2 and #3 for each reaction on Table 1 (see page 2). 5. Dispose of waste chemicals in appropriate waste container (ask instructor). 6. Clean and rinse all test tubes with water. 7. Return clean test tubes, water bottle and other items to where you obtained them originally (drawer or cabinet). If there's are reaction, predict the products and balance the equation. 1. Barium chloride and 3M sulfuric acid BaCl2 + H2SO4 ??? 2. Sodium chloride and silver nitrate. NaCl + AgNO3 ??? 3. Sodium chloride and potassium nitrate NaCl + KNO3 ??? 4. 3M sodium hydroxide and 6 M nitric acid. NaOH + HNO3 ??? 5. 3M sodium hydroxide and 6 M hydrochloric acid NaOH + HCl ??? 6. 6M ammonium hydroxide and 3M sulfuric acid. NH4OH + H2SO4 ??? 7. 6M ammonium hydroxide and iron(III) chloride. NH4OH + FeCl3 ??? 8. Ammonium chloride and copper(II) sulfate NH4Cl + CuSO4 ??? 9. Zinc nitrate and copper(II) sulfate Zn(NO3)2 + CuSO4 ??? 10. Sodium carbonate and calcium chloride. Na2CO3 + CaCl2 ??? 11. Sodium carbonate and 6M hydrochloric acid. Na2CO3 + HCl ???

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