น RCBC CHE116 General Chemistry I Laboratory Spring 2022 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 write balanced chemical equations for each single and double displacement reaction studied a 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 appears (cloudy, tiny particles) a 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 on page 4. 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. Page 1 of 7 Version 012022 E. Ostberg & L. Stewart Solubility Guidelines: lons that form soluble compounds (aq)... except when combined with Group Lions (Na+, Li+, K+, etc) no exceptions Ammonium (NH4+) no exceptions Nitrate (NO3-) no exceptions Acetate (CH3COO-) no exceptions Hydrogen carbonate (HCO3-) no exceptions Chlorate (CIO3-) no exceptions Halides (F-, Cl-, Br) Pb2+, Ag* and Hg22+ Sulfate (SO42-) Ag*, Ca2+, Sr2+, Ba2+, Hg22+ and Pb2+ lons that form insoluble compounds (s).......except when combined with.... Carbonate (CO32-) group I ions (Na+, Lit, etc) or (NH4+) 2+ Chromate (CrO42-) group lions (Na+, Lit, etc) or Ca2+, Mg2+ or (NH4+) Phosphate (PO43-) group lions (Na+, Li*, etc) or (NH4+) Sulfide (S2-) group I ions (Na+, Li*, etc) or (NH4+) Hydroxide (OH) group lions (Na+, Lit, etc) or Ca2+, Mg2+, Sr2+ or (NH4+) E. Ostberg & L. Stewart Version 012022 Page 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 (a 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 after the double displacement is in the gaseous state (AD or CB). One such example is hydrogen sulfide (H2S). 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) → H2O (1) + CO2 (g) - Sulfurous Acid H2SO3 (aq) → H2O (1) + SO2 (g) 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. a Safety Be especially cautious when using the 6 M acid and base solutions as they can burn your skin. Also be aware that skin discoloration will result from contact with AgNO3. Version 012022 Page 2 of E. Ostberg & L. Stewart AC CHE116 General Chemistry I Laboratory CE activity Series Table → Li (s) → 1 Lil+ (aq) + le- Highest Activity (easily oxidized) K(s) → Kl+ ) + 1+ + 2e- (aq) ( (aq) + le- Ba (s) + Ba2+ Ca (s) + Ca2+ Nas) → Nal+ (aq) + le- Ca²+ (aq) + 2e- - Mg(s) → 2+ (aq) → Mg2+ + 2e- Al(s) → ) A13+ (aq) + 3e- → Mn2+ Mn(s) + Mn2+ (aq) + 2e- Zn (s) → Zn2+ (aq) + 2e- Cr(s) → Cr3+ -> (aq) + 3e- Fe (s) ► Fe2+ (aq) + 2e- → Cd2+ s Cd (s) → - (aq) + 2e- Ni (s) - Sn (s) → → Ni2+ (aq) + 2e- → Sn2+ (aq) + 2e- Pb (s) + Pb2+ (aq) + 2e- H H2 (s) + 2 H+ (aq) Cu (s) + Cu2+ + 2e- → Cu2+ (aq) + 2e- Ag (s) → Agl+ (aq) + le- Hg (1) Hg2+ (aq) + 2e- → Au3+ (aq) + 3e- Lowest Activity (not easily oxidized) Au (s) → B en+ AR IM CHE116 General Chemistry I Laboratory Spring 2022 rocedure . a · 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 droppen • 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 • Perform the following reactions and record your observations in your notebook, in the order shown below. Note that some redox reactions take longer than others. If results are not obtained immediately, give the reaction some time. You may have to warm the test tube contents in the hot water bath in the hood. used. Sao All waste is to be disposed of in the plastic container in the hood. 1. Aqueous barium chloride + aqueous sodium sulfate + + 2. Aqueous sodium phosphate + aqueous barium chloride 3. Aqueous sodium phosphate + aqueous copper(II) sulfate - blue 4. Aqueous sodium phosphate + aqueous iron(III) chloride 5. Aqueous sodium phosphate + aqueous zinc nitrate 6. Aqueous sodium hydroxide + aqueous barium chloride 7. Aqueous sodium hydroxide + aqueous copper(II) sulfate 8. Aqueous sodium hydroxide + aqueous iron(III) chloride 9. Aqueous sodium hydroxide + aqueous zinc nitrate + 10. Hydrochloric acid (6 M) + aqueous sodium hydroxide (6 M) 11. Aqueous sodium carbonate + aqueous barium chloride 12. Aqueous sodium carbonate + aqueous copper(II) sulfate 13. Aqueous sodium carbonate + aqueous iron(III) chloride 14. Aqueous sodium carbonate + aqueous zinc nitrate 15. Aqueous sodium carbonate + aqueous sodium sulfate 16. Aluminum metal + hydrochloric acid 17. Copper metal + hydrochloric acid 18. Magnesium metal + hydrochloric acid 19. Zinc metal + hydrochloric acid E. Ostberg & L. Stewart Version 012022 Page 5