Chemical Reaction Essay

Chemical Reactions LabObjectives 1. To examine a mixture of reactions including precipitation, savage-base, gas forming, and oxidization-reduction reactions. 2. To range the yields formed in these reactions and summarize the chemic removes in terms of balanced chemical equivalences and lolly noodle comp ares. 3. To identify the species being oxidized and reduced in oxidation-reduction reactions and determine which species is the oxidizing constituent and the reducing agent. Chemical comparisons represent what occurs in a chemical reaction. For example, the equation HCl (aq) + NaOH (aq) NaCl (aq) + H2O (l) describes an acid-base reaction, a type of commutation reaction in which the control force is the formation of water. In an exchange reaction, the anion of single reactant changes places with the anion of the other reactant. closely exchange reactions take place in aqueous solutions. Other types of exchange reactions include precipitation and gas forming reactions . When a solution of lead (II) nitrate and sodium sulfate are mixed, you observe that a precipitate is formed.What is the individuation of the precipitate and what is the balanced molecular equation and net noodle equation describing this reaction? To determine the answers to these questions, you must first be able to create verb altogethery the CORRECT FORMULAS for the reactants and the products for this reaction. The following represents these formulas in an unbalanced chemical equation Pb(NO3)2 (aq) + Na2SO4 (aq) PbSO4 + NaNO3 Which product is the precipitate? One cannot know the answer to this question without using the solubility rules (Tro text, Table 4.1, p. 136). By using this slacken it can be heady that PbSO4 is an insoluble salt whereas NaNO3 is soluble. Consequently, one can keep the subscripts for the products indicating which product is the precipitate. Pb(NO3)2 (aq) + Na2SO4 (aq) PbSO4 (s) + NaNO3 (aq) Is this equation balanced? No. So, it now needs to be bal anced. Pb(NO3)2 (aq) + Na2SO4 (aq) PbSO4 (s) + 2 NaNO3 (aq) To write the net ionic equation, the above equation should be written as a complete ionic equation and then the spectator ions (the underlined ions) are cancelled. Pb2+ (aq) + 2 NO3- (aq) + 2 Na+ (aq) + SO42- (aq) PbSO4 (s) + 2 Na+ (aq) + 2 NO3- (aq) So, the net ionic equation for this precipitation reaction is Pb2+ (aq) + SO42- (aq) PbSO4 (s)Oxidation-reduction (redox) reactions are other important class ofchemical reactions. In redox reactions electrons are transferred from one substance to another. For example, if a copper wire is placed in a solution of silver-tonguedish nitrate a redox reaction occurs and silver coat is formed along with copper (II) nitrate. Oxidation numbers (0) (+1) (+2) (0) molecular(a) equation Cu (s) + 2 AgNO3 (aq) Cu(NO3)2 (aq) + 2 Ag (s) (0) (+1) (+2) (0)Net ionic equationCu (s) + 2 Ag+ (aq) Cu2+ (aq) + 2 Ag (s)The oxidation numbers for the metallic elements in this equation (See oxida tion number rules, Tro text, p. 148) learn us that copper metal is being oxidized while the silver ion is being reduced. Copper is therefore the reducing agent while silver nitrate is the oxidizing agent.PROCEDURE YOU NEED TO WEAR GOGGLES AT exclusively TIMES WHILE PERFORMING THIS EXPERIMENT. Chemical waste can be disposed of in the waste beakers supplied in the hoods. Part I stand in Reactions 1. Obtain 7 subaltern, clean test tubes. For the purposes of this lab, the test tubes need all be clean, not totally dry. A hose connected to the institutionalise supply in the hood may be usanced to readily remove most water from the test tubes. 2. Place 10 drops of 0.5 M CaCl2 into separately of the 7 test tubes. 3. Next, add 10 drops of 0.5 M solutions of each of the following solutions to the indicated test tubes, and record your observations. Allow at least 5 minutes for reactions to occur before disposing your solutions. Test Tube 1 2 MgSO4 (NH4)2C2O4 3 KNO3 4 Na3PO4 5 KBr 6 N aOH 7 K2CO34. Dispose of the solutions and some(prenominal) precipitates in the waste beakers located in the hoods. Wash your test tubes with lash and water. Rinse with tap water, then deionized water. 5. Add an amount equivalent to the sizing of a small pea of baking soda (sodium hydrogen carbonate) to a clean test tube. Add 10-20 drops of vinegar. (Vinegar is an aqueous solution of acetic acid, HC2H3O2). establish your observations. 6. IN THE HOOD, add an amount equivalent to the size of a small pea of sodium sulfite, Na2SO3, to a test tube. Add 10-20 drops of 6 M HCl. Record your observations.7. Put 10 drops of 0.5 M nitrous acid and 10 drops of 0.5 M phosphoric acid into separate test tubes. Add 1 drop of phenolphthalein to each test tube. Add drops of dilute (0.5 M) sodium hydroxide solution into each of the test tubes until a permanent color change is observed. (NOTE Phenolphthalein is an acid-base indicator that is colorless in acidic and neutral solutions, but strike ha rd in basic solutions). HINT When opus your net ionic equations nitric acid is a strong acid while phosphoric acid is a weak acid.Part II REDOX REACTIONS 8. Add a small piece of zinc to a test tube containing 30 drops of 6 M HCl and record what happens. 9. Add a 1 march piece of copper wire to a test tube containing 30 drops of 6 M HCl and record what happens. (Is copper an active metal or inactive metal with HCl? Look up an activity series of metals online to check). 10. IN THE HOOD, take a 2 inch piece of magnesium bay wreath and hold it with a pair of crucible tongs. Light the magnesium metal with a Bunsen burner and record your observations. DO NOT LOOK like a shot AT THE BURNING MAGNESIUM. LABORATORY REPORT Students willing write an individual(a) or group laboratory report at the discretion of the professor. admit the following information in your laboratory report, due at the get-go of the laboratory period next week. 1. Title. Title of the experiment, your recognize, your partners name and the date the laboratory was performed. 2. Introduction. This will be your opportunity to practice writing introductions. The introduction to the lab should be rough chemical reactions in habitual (why they are important, examples of specific types of chemical reactions such as combustion, precipitation, redox, etc.), not about how to write and balance an equation. For complete guidelines, go to Laboratory Reports on the Chem 1061 website. 3. experimental Details. A description of the procedure you followed to produce the experimental data and results. Alternatively, you may reference the procedure by citing the URLs (web addresses). 4. Results. A table or tables of your experimental data, clearly labeled with the proper units. Remember to use subscripts and superscripts where appropriate (examples cm3 or H2O). A neat table which includes your observations from the precipitation reactions (steps 2-3) should be included in a results section as well as each observations from the remainder of the reactions inparts I and II. 5. Discussion and Conclusion. For all the reactions observed (exchange reactions and redox), write the balanced molecular equation and net ionic equation for each reaction. For each reaction, place phase labels, (s), (l), (g), or (aq), later on each reactant and product. In addition,for the redox reactions in part II, indicate which reactant is the oxidizing agent and which one is the reducing agent. There is no need to write equations for combinations that produced no reaction. For each reaction that you observed and for which you write equations, you may provide any additional insights that you have into the reaction (was it easy/hard to observe, interesting things to note, etc.). You will also want to correlate things learned or observed with what you discussed in the introduction about reactions in general. 6. References. Citations and references to any sources you may have employ for the introduction or to per form, complete, or analyze the results of the lab. 7. Follow your instructors directions for submission of this lab report. If you submit by email, please attach a single file with a filename convention of Lastname Firstname Reactions and a overt line of Chem 1061 Reactions Lab.