Grade Level/Subject Chemistry grades 10 -12 Unit This is a culminating activity that should be attempted after teaching Le Chatelier’s principle I. Matter is classified by its chemical and physical properties II. Reactions occurring in both forward and reverse directions are reversible. Reversible reactions can reach a state of equilibrium, where the reaction rates of both the forward and reverse reactions are constant III. Le Chatelier’s principle indicates the qualitative prediction of direction of change with temperature, pressure and concentration IV. Techniques for experimentation involve the identification and proper use of chemicals and the description of equipment Enduring Understanding SOL Standards CH.1, CH.3 Title Le Chatelier’s Principle Inquiry Lesson Objective I. II. III. IV. Students will predict the shift in equilibrium when a system is subjected to a stress Students will identify and test factors that can cause a shift in equilibrium (temperature, pressure and concentration) Students will write chemical equations Techniques for experimentation involve the identification and proper use of chemicals and the description of equipment Inquiry Level 3 Materials Required Teachers should order 0.1 M cobalt chloride solution. Do not use powder and make it yourself. Inhalation can be toxic. Do not let students boil the liquids – slight heating is all that is required. Have hot plates kept on low. Acetone, Acid, distilled water, ice, and hotplates Le Chatelier’s Principle Inquiry Lab Co(H20) + Cl + heat ↔ CoCl2 + H2O Pink Blue After reviewing your notes on Le Chatelier’s Principle, plan and demonstrate at least 4 different “stresses” on the above reaction. Indicate the direction of change the reaction will undergo when each stress is applied to the system above. Place a description of each stress and the equilibrium shift you predict “before and after” in your lab book (include color photos or drawings). Materials : I. II. III. IV. Gather multiple (at least 4) test tubes and test tube racks, you will use the test tube to contain your shifts in equilibrium Labeling tape (remember to label the top of test tubes as to not block solutions) Obtain group sample of Cobalt Chloride solution (~20 ml per group) Pipettes - to transfer cobalt chloride solution to test tube for manipulation Safety Follow all safety instructions given! Cobalt Chloride solution can be harmful if ingested, Hot plates are HOT, Acids are dangerous, Acetone is flammable, etc. Wear goggles, tie back hair, keep your work area clean, and pay attention to your surroundings. Do not bring any solution to a boil. Hot plates must be kept on LOW! You may or may not need the following: Hydrochloric acid 3M Ice Acetone Hot plate Thermometer Distilled water Vacuum jar Other All used solutions are to be disposed according to your teacher’s instructions! Discussion: I. II. Using complete thoughts and complete sentences, please explain your logic for each of the 4 shift in equilibrium predictions you made. Are the shifts in equilibriums chemical reactions? Explain why or why not. Extensions: Research the Haber process online. How is the Haber process applicable to this lab? Record the chemical equilibrium in your lab book with the online web addresses used for this information. The human body contains enough carbon to provide 'lead' (which is really graphite) for about 9,000 pencils.