Experiment 6: Chemical Reactions and the Activity Series (This experiment was adapted from two experiments from Santa Monica College: CH10 Chemical Reactivity and Types of Chemical Reactions.) Purpose: a) To perform and observe the results of a variety of single and double displacement reactions b) To become familiar with some of the observable signs of these reactions c) To identify the products formed in each of these reactions d) To establish an activity series based on experiment observations e) To write balanced chemical equations for each single and double displacement reaction studied Background During a chemical reaction both the form and composition of matter are changed. Old substances are converted to new substances, which have unique physical and chemical properties of their own. Some of the observable signs that a chemical reaction has occurred include the following: . A metallic deposit appears . Bubbles appear . A temperature change occurs . A color change occurs . A precipitate (cloudy, tiny particles) appears Single Displacement Reactions All single displacement reactions have the general form: A + BC - B + AC Here, A is an element and BC is usually an aqueous ionic compound or an acid (consisting of B* and C-aqueous ions). A displaces B in BC, resulting in the formation of a new element B and a new ionic compound or acid, AC. If the new element B is a metal, it will appear as a solid. If it is a gas, it will appear as bubbles An Activity Series of elements is often used to determine if A will displace B in a single displacement reaction. An Activity Series is provided in this Background section. As a rule, if A has a higher activity that B, a single displacement reaction will occur. However, if A has lower activity than B, a single displacement reaction will not occur.Double Displacement Reactions All double displacement reactions have the general form: AB + CD - AD + CB Reactions that can be classified as double displacements include precipitation reactions, neutralization reactions, and gas forming reactions. Precipitation Reactions Here AB and CD are usually aqueous ionic compounds (or acids) consisting of aqueous ions (At and B-, C* and D-). When a double displacement reaction occurs, the cations and anions switch partners, resulting in the formation of two new ionic compounds AD and CB, one of which is in the solid state. This solid product is an insoluble ionic compound called a precipitate. To determine whether a product compound will be soluble (aq) or insoluble (s), consult the Solubility Rules. Note that if both of the predicted products are soluble, a precipitation reaction will not occur. Neutralization Reactions Here AB is an acid (consisting of H* and X- aqueous ions) and BC is a base (consisting of M* and OH-ions). When a double displacement reaction occurs, the cations and anions switch partners, resulting in the formation of water and a new ionic compound (or salt), which is usually soluble. Neutralization reactions are exothermic, and are generally accompanied by a noticeable release of heat. Gas Forming Reactions In these reactions one of the products (AD or CB) after the double displacement is in the gaseous state. One such example is hydrogen sulfide (HS). However, one of the products could also be carbonic acid (H2CO3) or sulfurous acid (H2SO3). Both carbonic acid and sulfurous acid are unstable and will decompose to form carbon dioxide and sulfur dioxide gases, respectively: Carbonic acid H2CO3 (aq) - H20 (1) + CO2 (g) Sulfurous Acid H2SO3 (aq) - H20 (1) + SO2 (9) Writing Equations for Reactions . Write the correct formulas for each reactant and place a yield arrow (-) after the last reactant. . Identify the reaction type (single or double displacement) . If you determine that a reaction will occur, write the correct formula(s) of the products after the arrow. If you determine that a reaction will not occur, simply write "no reaction" after the arrow . Balance the equation . Be sure to include the physical states of all reactants and products in your final equation.Solubility Rules and Activity Series SOLUBILITY RULES ACTIVITY SERIES 1. Alkali metal compounds, acetates, Highest Acivity nitrates, and ammonium compounds are LI all soluble 2. Hydroxides of alkali metals and NH,*1, Ca*2, Sr+2, and Ba*2 are soluble. All others are Ca insoluble Na 3. All halides (chlorides etc.) are soluble except for those containing Ag*1, Pb*, and Hg2*2. 4. Most sulfates are soluble, except for BaSO4, SrS04, AgaSO4, PbSO4, and CaSO4. 5. Most phosphates, carbonates, chromates and sulfides are insoluble (except those of the alkali metals and ammonium). 6. In addition, all acids are soluble! lowest activity Safety Be especially cautious when using the 6 M acid and base solutions as they can burn your ski Also be aware that skin discoloration will result from contact with AgNO3. Chemicals Metals: Aluminum, Copper, Zinc, Magnesium Solids Compounds: sodium bicarbonate Solutions: 6M sodium hydroxide 6M hydrochloric acid 5% acetic acid All of the following solutions are 0.1 M: barium chloride, copper(II) sulfate, iron(III) chloride, silver nitrate, sodium carbonate, sodium hydroxide, sodium phosphate, sodium sulfate, zinc nitrate. Equipment 10 small test tubes test tube rack Parafilm plastic dropperProcedure Always reuse clean test tubes that have been rinsed with distilled water. The test tubes do not have to be dry. At the end of this experiment, do a final rinse of your test tubes and dispose of them in the broken glass container. . Use approximately 2 mL quantities of all solutions (about the stem of a plastic dropper) . For reactions involving metals, use just 1-2 pieces of each metal. Place the metal in the test tube first, and then add the solution. The metal should be completely immersed in the solution used . Perform the following reactions and record your observations in your notebook, in the order shown below. Note that some reactions take longer than others. If results are not obtained immediately, give the reaction some time. All waste is to be disposed of in the plastic container in the hood. 1. Solid sodium bicarbonate + acetic acid 2. Solid sodium bicarbonate + hydrochloric acid 3. Solid sodium bicarbonate + aqueous sodium hydroxide 4. Aqueous barium chloride + aqueous sodium sulfate 5. Aqueous sodium phosphate + aqueous barium chloride 6. Aqueous sodium phosphate + aqueous copper(II) sulfate 7. Aqueous sodium phosphate + aqueous iron(III) chloride 8. Aqueous sodium phosphate + aqueous zinc nitrate 9. Aqueous sodium hydroxide + aqueous barium chloride 10. Aqueous sodium hydroxide + aqueous copper(II) sulfate 11. Aqueous sodium hydroxide + aqueous iron(Ill) chloride 12. Aqueous sodium hydroxide + aqueous zinc nitrate 13. Hydrochloric acid (6 M) + aqueous sodium hydroxide (6 M) 14. Aqueous sodium carbonate + aqueous barium chloride 15. Aqueous sodium carbonate + aqueous copper(II) sulfate 16. Aqueous sodium carbonate + aqueous iron(III) chloride 17. Aqueous sodium carbonate + aqueous zinc nitrate 18. Aqueous sodium carbonate + aqueous sodium sulfate 19. Aluminum metal + hydrochloric acid 20. Copper metal + hydrochloric acid 21. Magnesium metal + acetic acid 22. Zinc metal + hydrochloric acid23. Aluminum metal + iron(III) chloride 24. Copper metal + iron(III) chloride 25. Magnesium metal + iron(Ill) chloride 26. Zinc metal + iron(Ill) chloride 27. Aluminum metal + zinc nitrate 28. Copper metal + zinc nitrate 29. Magnesium metal + zinc nitrate 30. Aluminum metal + copper(II) sulfate 31. Magnesium metal + copper(II) sulfate 32. Zinc metal + copper(Il) sulfate 33. Copper metal + aqueous silver nitrate . When finished, complete your notebook by writing the balanced chemical equation for each reaction studied (see post-lab questions). Post-lab Question (Write the answers in your lab notebook.) 1) Write a balanced chemical equation for each reaction, numbered 1 - 33, in the order shown above. Be sure to include the states of all compounds in your equations (solid, liquid, aqueous, or gas). If no reaction occurred write the words "no reaction" on the right side of the reaction arrow. Explain why no reaction occurred (use the solubility rules or activity series). 2) Arrange aluminum, copper, magnesium, silver, zinc, and hydrogen in order of reactivity from most active to least active on the basis of the results from the reactions that you performed. This is already listed in the Activity Series, however, explain why you put the metals in the order you did, based on the results of your chemical reactions. most active (most easily oxidized) to least active