Determining the Relative Strengths of Oxidizing Agents in Redox Reactions

LAB 4 –UNDERSTANDING OXIDIZING STRENGTHS IN REDOX REACTIONS– LAB REPORT CHM 2045L -Dr. Yavuz Petrowski The statement is: “I certify that this is my own work and I understand that if I am found to be in violation of the honor code, I will be subject to the highest penalty”. INITIAL: MJ Name: Melissa Jimenez Znumber: Z23743913 PRELAB: Background: Please complete the following sections. Purpose of the experiment: In your own words, the purpose of the experiment including a brief description of the lab and the reason for doing the experiment (what we are trying to determine and how we will go about determining it). Explain the concepts we are investigating; explain why and how they are useful, how those concepts apply to the experiment; show relevant equations if you need to. The purpose of the experiment is to determine the strengths of oxidizing agents and to determine whether a reaction will occur. The concepts used in the lab was oxidation reaction which can be explained as when a substance gains more than one electron, an example would be a rusting fence .In the lab multiple chemical combinations were mixed and observed to determine if a redox reaction had occurred. If a reaction had occurred you were supposed to identify the process and explain the possible reason behind the reaction. Flow Chart: Complete experimental procedure for this experiment by using information provided in the power point and 360 experimental video in a flow diagram format. A flow chart indicates the procedure of how experiment is performed. The flow chart must be written in the correct flow chart format (box and arrow). Handwritten flow charts are not accepted. See the example of the flow chart in canvas module. Measure 2.0 mL of FeCl3 then put it inside of the beaker. Measure 2.0 mL of NaOCl and put inside of test tube.Using a pipette, add 10 drops of KMnO4 in the test tube and add the starch into the test tube.Measure 2.0 mL of starch and stir carefully. Measure 2.0 mL of the test tube solution and transfer, then add 1.0 mL of HNO3 into the test tube then stir. In the other test tube add one drop of CU.Measure 2.0 mL of HCl and put into two different test tubes. In one of the test tubes add 1 drop of Zn. Record your observations for both and document the data. Waste Collection: Type out the chemicals used in this experiment, and their hazards if applicable, and any other safety concerns associated with this experiment. You can search for the Materials Safety Data Sheet document on the internet to list hazards and safety concerns. You can add an extra row if you need extra space. Chemicals Safety Hazard HNO3 Can cause eye, throat, and respiratory irritation NaHSO3 Can be dangerous if it comes into contact with eyes and skin. If inhaled it can cause severe irritation to nose and throat. NaOCl Can cause skin and eye irritation. May also be corrosive to other metals FeCl3 Can be corrosive and cause severe irritation to skin and eyes if it touches you. Kl May cause mild irritation to the skin and eyes. Dangerous if ingested or inhaled KBr High concentrations of this chemical can cause nausea and sometimes vomiting HCl Extremely corrosive , can cause burns to skin and react with metals to form a flammable gas KMNO4 Can cause irritation of the skin and eyes, also is extremely flammable. DATA ANALYSIS Handwritten lab reports are not accepted SYSTEM #1: 2FeCl3 + 2KI 2FeCl2 + 2KCl + I2 For System 1 reaction, record your observations below. Did a redox reaction occur? Explain what your observations indicate about the redox reaction. If a reaction occurred complete questions 3-7. Which atom is oxidized, and what are its initial and final oxidation numbers? Which atom is reduced, and what are its initial and final oxidation numbers? The atom that is reduced is iron since its oxidation state decreases from 3+ to 2+. Write the half equation for the oxidation reaction. 2I^- - 2e= I2 Write the half equation for the reduction reaction. Fe^3+ + e= Fe^2+ What other ions are in solution, and what are their roles? The other ions in the solution are K+ and Cl-, they act as spectator ions. SYSTEM 2: 2MnO4 - + H + + 5HSO3 - 2Mn 2+ + 5 SO4 2- +3H2O Record your observations below. At first the solution is a purple color since there is MNO4^- after adding the MN^2+ it turns clear. Did a redox reaction occur? Explain what your observations indicate about the redox reaction. If a reaction occurred complete questions 10-16. Which atom is oxidized, and what are its initial and final oxidation numbers? The atom that oxidized is sulfur, the initial number was 4+ and the final oxidation number was 6+. Which atom is reduced, and what are its initial and final oxidation numbers? The atom that was reduced was manganese the initial number was 7+ and the final number was 2+. Which substance (not atom) is being oxidized? Which substance (not atom) is being reduced? Write the half equation for the oxidation reaction. HSO3^- = SO4^2- +2e Write the half equation for the reduction reaction. MNO4^- + 5e^- +8H^+=MN^2+ + 4H2O After the reaction is complete, what other ions are in solution and what are their roles? H- is left in the solution and its role is to balance the charge on both sides of the reaction. SYSTEM 3: OCl - + 2Br - + H2O Cl - + Br2 + 2OH- Record your observations below. The solution changed from a clear color to a yellow color. Based on your observations, d id a redox reaction occur? Explain what your observations indicate about the redox reaction. If a reaction occurred complete questions 19-25. Which atom is oxidized, and what are its initial and final oxidation numbers? The atom that was oxidized was Bromine, it started with the initial number of -1 and its final oxidation number was 0. Which atom is reduced, and what are its initial and final oxidation numbers? The atom reduced was Chlorine, which started off as 1+ and ended with its final oxidation number 1-. Which substance (not atom) is being oxidized? Which substance (not atom) is being reduced? Write the half equation for the oxidation reaction. 2Br=Br2+2e- Write the half equation for the reduction reaction. 2e- + H2O + OCl= Cl- +2OH- What other ions are in solution and what are their roles? SYSTEM 4: Reaction of acids with metals Is there any chemical reaction between Zinc metal or powder and 1.0 M HCl? If there is, write balanced chemical equation for these reactions. Record your observations for the reaction of zinc metal and acid below. When either was added to the other bubbles began to form indicating there was gas being released. 28. Record your observations for the reaction of copper metal and acid below. There was no reaction to be observed. CONSIDERATION FOR DISCUSSION & CONCLUSION As you write your discussion and conclusion paragraphs for the discussion assay, here are some tips and questions you should answer. These are in addition to the "Guidelines for a good discussion and conclusion" document in the introduction module. List five types of chemical reactions. What is the proof of chemical reactions? Explain according to the experimental results. Be specific. What are the common properties of oxidation and reduction reactions? Explain one of the systems in which you observed oxidation and reduction reactions. How did you determine if it is an oxidation and reduction reaction? What are spectator ions? Did you include your spectator ions in molecular and complete ionic equations? In which cases where spectator ions are not included in chemical equations? In system 4. did both metals react with HCl? If it did not explain the reason. DISCUSSION & CONCLUSION ASSAY In this experiment the goal was to investigate the various types of chemical reactions focusing mainly on redox reactions. There are several key indicators for this reaction such as changes in the color of a solution and the production of gas, which was used as evidence for these chemical transformations. The common properties of oxidation and reduction reaction are electron transfer along with changes in the oxidation state. These properties were also observed in one of the systems in which the electron movement was tracked to confirm that it was a redox reaction occurring. The role of the spectator ion was discussed this is because while they are included in certain equations such as complete ionic equations, they were excluded from net ionic equations since they don’t precipitate in the reaction or contribute much. Furthermore, in system 4 it was found that not all metal reacted with HCl, which can be the result of difference in their reactivity. All in all the experiment done today furthered our understanding of chemical reactions along with the principles of redox processes.