Lab 3: Precipitation Reactions in Solution

Lab 3 –Precipitation Reactions in Solutions– 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” 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 this experiment was to determine the solubility of different kinds of compounds and polyatomic ions by experimenting with various substances. The second part of the lab was used to evaluate the reactions taking place to determine whether these reactions were precipitation reactions. From there our understanding of balancing equations and solving various equations was used to write out the compounds formed. 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. Set up your solutions, toothpicks, and well plate Add CuSO4,CoCl2,NaOH,Na2CrO4, and KlO3 into the dividers, each solution in a different divider Use 2-3 drops of AgNO3 into each of the well on the plate Repeat with the next compound mixing CuSO4 with each of the other chemicals and record your findings Record your findingsObserve the colors in each section and see if a solid precipitate has formed and in which well Repeat until all samples have been tested wit each other and you have evaluated all the reactions 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 AgNO3 Causes nausea, vomiting ,headaches, and skin irritation CuSO4 Toxic if ingested, can cause irritation to eyes and skin NaOH Can cause respiratory problems, nausea , and burns to the skin CoCl2 Can cause respiratory issues and is also a skin irritant KlO3 Can cause irritation to eyes, skin, and respiratory tract NaCrO4 Can be toxic when ingested or inhaled, and can cause harm to the respiratory system PRE- DISCUSSION QUESTIONS Pb(NO 3 ) 2( aq ) + (NH 4 ) 2 S ( aq ) Pb(NO3)2 is soluble however (NH4)2S is usually soluble except for sulfide of group 2 metals Balanced-- Pb(NO3)2 (aq) + (NH4)2S(aq) = PbS (s) + 2NH4(NO3) (aq) Complete-- Pb ^+2 (aq) +2(NO3)^- (aq) +2(NH4)^+ (aq) +S^-2 (aq) = PbS (s) +2(NH4)^+ (aq) + 1(NO3) ( aq) Net Ionic— Pb ^+2 (aq) + S^2- (aq) = PbS (s) FeSO 4( aq ) + AgNO 3( aq ) CuCl 2( aq ) + NaOH ( aq ) KI (aq) + Pb(NO 3 ) 2 (aq) Data table for precipitation reactions: Observation can be written as for no reaction: NR, for precipitate: PPT, and if only color changes, color of the solution in the table. Please complete both sections of the observations. Na2CrO4 KIO3 3. 4. 5. White PPT Brown PPT Red PPT White PPT 1. 6. 7. 8. 9. No PPT No PPT Blue PPT Yellow PPT No PPT AgNO3 AgNO3 CuSO4 CoCl2 NaOH Na2CrO4 KIO3 CuSO4 CoCl2 NaOH 1. 2. No PPT 2. 6. 10. 11. 12. White PPT No PPT Blue PPT Orange PPT No PPT 3. 7. 10. 13. 14. Brown PPT Blue PPT Blue PPT No PPT No PPT 4. 8. 11. 13. 15. Red PPT Yellow PPT Orange PPT No PPT No PPT 5. 9. 12. 14. 15. White PPT No PPT No PPT No PPT No PPT Write the balanced, complete, and net ionic equations for each precipitation reaction given in the table shown. The data table indicates the fifteen performed reactions. Make sure to write a B.E., C.I.E. and an N.I.E. for those reactions only where you observed a precipitate formation. Make sure to balance equations, show charges and states of the reagents in the reaction. Show the equations below: Write the balanced, complete, and net ionic equations for only precipitation reactions. AgNO 3 ( aq ) + CuSO 4 ( aq ) Balanced Eq. C. I. E. N. I. E. AgNO 3 ( aq ) + CoCl 2 ( aq ) Balanced Eq. C. I. E. N. I. E. AgNO 3 ( aq ) + NaOH ( aq ) Balanced Eq. C. I. E. N. I. E. AgNO 3 ( aq ) +Na 2 CrO 4 ( aq ) Balanced Eq. C. I. E. N. I. E. AgNO 3 ( aq ) + KIO 3 ( aq ) Balanced Eq. C. I. E. N. I. E. CuSO 4 ( aq ) + CoCl 2 ( aq ) Balanced Eq. C. I. E. N. I. E. CuSO 4 ( aq ) + NaOH ( aq ) Balanced Eq. C. I. E. N. I. E. CuSO 4 ( aq ) + Na 2 CrO 4 ( aq ) Balanced Eq. C. I. E. N. I. E. CuSO 4 ( aq ) + KIO 3 ( aq ) Balanced Eq. C. I. E. N. I. E. CoCl 2 ( aq ) + NaOH ( aq ) Balanced Eq. C. I. E. N. I. E. CoCl 2 ( aq ) + Na 2 CrO 4 ( aq ) Balanced Eq. C. I. E. N. I. E. CoCl 2 ( aq ) + KIO 3 ( aq ) Balanced Eq. C. I. E. N. I. E. NaOH ( aq ) + Na 2 CrO 4 ( aq ) Balanced Eq. C. I. E. N. I. E. NaOH ( aq ) + KIO 3 ( aq ) Balanced Eq. C. I. E. N. I. E. Na 2 CrO 4 ( aq ) + KIO 3 ( aq ) Balanced Eq. C. I. E. N. I. E. 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. How do you define a precipitation reaction and explain the role of solubility rules in predicting precipitate formation? Did you have any difficulties determining whether the precipitation formed? If you did, how did you overcome the problem? Did you use a solubility chart in that instance to confirm the precipitation? Reflect on what you have learned from the experiment. Consider how your understanding of precipitation reactions has evolved and how you will us this knowledge for the next experiments in this course. DISCUSSION & CONCLUSION ASSAY A precipitation reaction is a certain kind of chemical reaction where two aqueous solutions are combined and mixed, and as a result, a solid product called a precipitate is formed and separates from the solution. This happens when products of the reaction are insoluble in water, resulting in the products transforming into a solid. The solubility rule plays a critical role in whether a precipitate will form, this is done by providing guidelines on the solubility of certain ionic compounds in water. The rules are helpful in determining if any of the products will be insoluble, which in turn indicates a precipitation reaction. During the experiment, there were some difficulties, for example, it was hard to determine whether a precipitate had formed, especially when the changes were subtle, or when the precipitate was very fine, it became hard to detect. To overcome these difficulties, using the solubility chart to confirm the solubility of the products during the experiment helped clarify whether a precipitate was going to form. Reflecting on what was learned in the lab, my understanding of precipitation reaction has been expanded, I know have a better grasp on the concept of solubility rules and how they help interpret experimental observations. The knowledge gained from this lab will be used in the future for other labs, since it will help me efficiently analyze reaction outcomes, predict whether a precipitate will form, along with confirm future findings using the solubility principles.