Contributors: JoLyn & Maria
October 25, 2012
Abstract: The purpose of this experiment was inform students of oscillating reactions, and how to create an oscillating reaction. The experiment allowed for students to use certain values in order to calculate the amounts of several needed solutes. It taught students more understanding on dimensional analysis and correct units. Another purpose was the use of balancing and understanding equations. The ability to recognize a chemical equation as having a reaction and what the reaction produces. The solution in an oscillation reaction changes colors from white - amber - blue and back to white. In the reaction, gas is released and a solid should form. The experiment had a lot of success and changed colors for approximately 10-20 minutes.
Introduction: An oscillating reaction is a type of chemical reaction which the concentrations of the products and reactants change periodically, either with time or with position in the reacting medium (Oxford Dictionary of Chemistry). This oscillating effect implies that the concentration may increase, decrease, maximize or minimize over a period of time. Interaction with an additional substance in the reaction medium causes the system to oscillate between the states as the concentrations change (Answers Corporation). The following chemicals are used in this experiment: Malonic acid is a white crystalline acid, derived from malic acid and used in making barbiturates (Farlex). Manganese sulfate monohydrate is a white or pink powder or granular, irritant and soluble in water (Rech Cehmical Co. Ltd.). Potassium iodate is a strong oxidizing agent, meaning in a chemical reaction, this ionic compound supports the transfer of oxygen atoms to other elements and compounds (Adams). Sulfuric acid is an oily, colorless liquid with no odor and is known as a key component in batteries (Wisegeek). Hydrogen peroxide is a colorless, highly reactive chemical containing hydrogen and oxygen (Scientific Committes). All these chemicals will be mixed with one of the other and will all be mixed in the completion of this experiment.
Procedure: The procedure followed was, "Solution Preparation: an Oscillating Reaction" used Fall 2012, Chemistry 120. All chemicals used were malonic acid, manganese sulfate monohydrate, potassium iodate, sulfuric acid, and hydrogen peroxide. At least three volumetric flasks were used, three 10mL graduated cylinders, and one 100mL beaker. In order to do this experiment, several calculations were incorporated. The calculation of the amount of solute needed per solution. Then added the solute(s) to volumetric flasks such that the meniscus of the solution "sits" on the etched line. Then mixed solutions as directed to begin the reaction. The experiment included preparation of solutions of the solid-into-liquid type, dilution of a more concentrated molarity type, and dilution of a percentage by weight type. After each solution was made and covered, the final step was prepared. We added four drops on solution D to a 100mL beaker, measured out 10mL of each solution into SEPERATE 10mL graduated cylinders and poured them into the beaker simultaneously.
Results: In order for the solution to be mixed properly, each solute measurement needed to be calculated. The number of grams of malonic acid and manganese sulfate were 0.78 grams of malonic acid and 0.169 grams on manganese sulfate monohydrate. The number of grams needed for 50mL of 0.2 M solution is 2.14 grams of potassium iodate. In the dilution, the amount of 0.8 M sulfuric acid was 5mL. In calculations involving percentages, 0.006 grams is equivilent to four drops of starch. There were 3.062 grams of hydrogen peroxide in 25.0mL of 3.6M hydrogen