Lab 5: Limiting Reagent Study

Lab 5 –Limiting Reagent Study– Lab Report C H M 2 0 4 5 L - D r. Y a v u z P e t r o w s k i The statement is: “I cer fy that this is my own work and I understand that if I am found to be in viola on of the honor code, I will be subject to the highest penalty” Name: Jetzebell Callens Znumber: 23744291 PRELAB Background: Please complete the following sec ons. Purpose of the experiment: In your own words, the purpose of the experiment including a brief descrip on 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 inves ga ng; explain why and how they are useful, and how those concepts apply to the experiment; show relevant equa ons if you need to. The purpose of this experiment is to explore the formation of insoluble cobalt carbonate (CoCO₃) by reacting cobalt chloride (CoCl₂) with sodium carbonate (Na₂CO₃) in varying ratios. By mixing these solutions in six different proportions, we aim to identify the limiting reagent for each reaction and examine how this impacts the amount of CoCO₃ precipitate formed. The balanced chemical equation for the reaction is CoCl2 (aq)+Na2CO3(aq)→CoCO3(s)+2NaCl(aq), indicating that one mole of CoCl₂ reacts with one mole of Na₂CO₃ to produce one mole of CoCO₃. Once the solutions are combined, the formation of CoCO₃ will lead to a visible precipitate. We will measure the height of this precipitate as a means of quantifying the amount of cobalt carbonate produced. To verify our predictions about which reactant is limiting, we will analyze the supernatant liquid—testing it for unreacted ions through speci c chemical experiments. For example, we might use indicators that react with excess sodium ions or chloride ions, con rming their presence or absence in the supernatant. ti ti ti ti fi fi fi ti fi ti ti This experiment is signi cant because it reinforces essential concepts in stoichiometry, including the understanding of limiting reagents and the principles of precipitation reactions. Such knowledge is crucial in various applications, including industrial chemical processes, environmental science, and laboratory techniques. By performing this experiment, we gain hands-on experience in measuring and analyzing chemical reactions, skills that are foundational in scienti c research and practical applications. Flow Chart: Complete the experimental procedure for this experiment by using the informa on provided in the power point and 360 experimental videos in a ow diagram format. A ow chart indicates the procedure of how the experiment is performed. The ow chart must be wri en in the correct ow chart format (box and arrow). Handwri en ow charts are not accepted. See the example of the ow chart in the canvas module. Waste Collec on: Type out the chemicals used in this experiment, 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 CoCl2 Toxic if inhaled or ingested; may cause skin and eye irrita on. Cobalt compounds can be sensi zers, leading to allergic reac ons. Na2CO3 Generally considered safe, but can cause irrita on to the skin, eyes, and respiratory tract. CoCO3 Toxic and may cause skin and eye irrita on. Prolonged exposure can lead to respiratory issues. 2NaCl Generally low toxicity but can cause irrita on if ingested or in contact with skin. High concentra ons can lead to health issues. CO3^2- Typically low toxicity, but strong bases or acids can react with carbonate ions, causing hazardous condi ons (e.g., release of carbon dioxide). Co2 Cobalt dust can be harmful if inhaled, and it can cause skin sensi za on. Chronic exposure is ti fl tt fl fl fl tt ti ti ti ti ti ti fl ti ti ti fl ti ti linked to lung disease. Data Process YOU MUST SHOW ALL YOUR CALCULATIONS TO RECEIVE CREDIT FOR THEM! Proper use of signi cant gures and units is part of the grading. PART I: for CoCl2 TEST-TUBE TEST-TUBE TEST-TUBE TEST-TUBE TEST-TUBE TEST-TUBE #1 #2 #3 #4 #5 #6 Concentra on The volume 0.10 M 2.00 mL 3.00 mL 4.00 mL 6.00 mL 7.50 mL 10.00 mL 0.0002mol 0.0003mol 0.0004mol 0.0006 mol 0.00075mo 0.001 mol delivered (mL) Moles of CoCl2 l For Na2CO3 Test-tube #1 Test-tube #2 Test-tube #3 Concentra on The volume Test-tube #4 Test-tube #5 Test-tube #6 0.10 M 13.00 mL 12.00 mL 11.00 mL 9.00 mL 7.50 mL 5.00 mL 0.0013 0.0012 0.0011 0.0009 0.00075 0.0005 delivered (mL) Moles of Na2CO3 Volume Measurements Height of Test-tube #1 Test-tube #2 Test-tube #3 Test-tube #4 Test-tube #5 Test-tube #6 5.5 cm 6.5 cm 7.0 cm 9.0 cm 9.5 cm 8.5 cm Clear blue Clear Clear Cloudy Cloudy Clear pink purple purple purple/ light pink precipitate formed (cm) Color of supernatant liquid observed. pink Color of Cloudy Cloudy Cloudy Cloudy Cloudy Cloudy precipitate blue purple/ purple purple/ light pink dark pink blue fi fi ti ti observed. pink Calcula ons: Complete mol calcula ons for CoCl2 and Na2CO3 by using the informa on table given in the instruc ons le, and/or PowerPoint and 360 Lab video. Handwri en calcula ons are not acceptable. If the student submits a handwri en calcula on, the assignment will be graded with a 4-point deduc on. CoCl2: Test tube 1: 2.00 mL x 1 L/1000 mL x 0.1 mol/1 L= 0.0002 mol Test tube 2: 3.00 mL x 1 L/1000 mL x 0.1 mol/1 L= 0.0003 mol Test tube 3: 4.00 mL x 1 L/1000 mL x 0.1 mol/1 L= 0.0004 mol Test tube 4: 6.00 mL x 1 L/1000 mL x 0.1 mol/1 L= 0.0006 mol Test tube 5: 7.5 mL x 1 L/1000 mL x 0.1 mol/1 L= 0.00075 mol Test tube 6: 10.00 mL x 1 L/1000 mL x 0.1 mol/1 L= 0.001 mol NaCO3: Test tube 1: 13.00 mL x 1 L/1000 mL x 0.1 mol/1 L = 0.0013 mol Test tube 2: 12.00 mL x 1 L/1000 mL x 0.1 mol/1 L = 0.0012 mol Test tube 3: 11.00 mL x 1 L/1000 mL x 0.1 mol/1 L = 0.0011 mol Test tube 4: 9.00 mL x 1 L/1000 mL x 0.1 mol/1 L = 0.0009 mol Test tube 5: 7.5 mL x 1 L/1000 mL x 0.1 mol/1 L= 0.00075 mol Test tube 6: 5.00 mL x 1 L/1000 mL x 0.1 mol/1 L = 0.0005 mol Predic ons of Limi ng Reagent: This sec on can be completed while wai ng for the precipitate to se le. TEST-TUBE TEST-TUBE TEST-TUBE TEST-TUBE TEST-TUBE TEST-TUBE #1 #2 #3 #4 #5 #6 Excess Co2+ or CO3^2- CO3^2- CO3^2- CO3^2- N/A Co2+ 0 0 0 0 0 0.0005 0.0011 0.0009 0.0007 0.0003 0 0 2 x 10^-4 3 x 10^-3 4 x 10^-4 6 x 10^-4 7.5 x 10^-4 5 x 10^-4 CO32- present? Moles of Co2+ in excess Moles of CO32- in excess Theore cal Yield of CoCO3 (moles) ti ti ti tt ti tt ti ti ti ti fi ti ti fi ti ti ti ti tt PART II: Veri ca on of Limi ng Reagent Observa ons of Test-tube #1 Test-tube #2 Test-tube #3 Test-tube #4 Test-tube #5 Test-tube #6 precipitate forma on Reac on of NR NR NR NR NR Reac on of WHITE White PPT White PPT White PPT NR supernatant liquid PPT PPTPurple supernatant liq. with Na3PO4 NR with BaCl2 Calcula ons: Complete mol calcula ons for excess CoCl2 and Na2CO3 by using the informa on table given in the instruc ons le, and/or power point and 360 Lab video and include theore cal yield calcula ons. Handwri en calcula ons are not acceptable. If the student submits a handwri en calcula on, the assignment will be graded with a 4-point deduc on. Excess in Co2+: Test tube 6: 0.001 mol – 0.0005 mol = 0.0005 mol Excess in CO32-: Test tube 1: 0.0013 mol – 0.0002 mol = 0.0011 mol Test tube 2: 0.0012 mol – 0.0003 mol = 0.0009 mol Test tube 3: 0.0011 mol – 0.0004 mol = 0.0007 mol Test tube 4: 0.0009 mol – 0.0006 mol = 0.0003 mol CONSIDERATION FOR DISCUSSION & CONCLUSION As you write your discussion and conclusion paragraphs for the discussion assay, here are some ps and ques ons you should answer. These are in addi on to the "Guidelines for a good discussion and conclusion" document in the introduc on module. • Goal of the experiment • What is limi ng reagent and how important in prac cal applica ons? Were your predic ons for which ion was in exceed veri ed by Part II of experiment? Explain. • How did you determine the point at which a reagent from part I becomes the limi ng reagent for the reac on? Does the molar ra o have an e ect on which reagent is the limi ng reactant? Explain. • What is the di erence between theore cal and percent yield? Why did you calculate the theore cal yield for your experiment? Would it be possible to calculate the experimental yield for your experiment and what informa on you would need? • Conclusion ti ti ti ti ti ti ti ti tt ti ti ti ti ff ti ti ti ti ti ti fi fi ff ti ti ti ti tt ti ti ti ti ti ti DISCUSSION & CONCLUSION ASSAY THE GOAL OF THIS EXPERIMENT WAS TO EXPLORE HOW COBALT CARBONATE (COCO₃) IS FORMED BY MIXING COBALT CHLORIDE (COCL₂) WITH SODIUM CARBONATE (NA₂CO₃) IN DIFFERENT RATIOS. A LIMITING REAGENT IS THE REACTANT THAT RUNS OUT FIRST DURING A REACTION, AND IT DETERMINES HOW MUCH PRODUCT CAN BE MADE. UNDERSTANDING WHICH REACTANT IS LIMITING IS IMPORTANT IN REAL-WORLD APPLICATIONS, SUCH AS IN FACTORIES WHERE USING THE RIGHT AMOUNTS OF MATERIALS CAN SAVE MONEY AND REDUCE WASTE. IN PART II OF THE EXPERIMENT, WE TESTED OUR PREDICTIONS ABOUT WHICH REACTANT WOULD BE IN EXCESS. WE CONFIRMED OUR IDEAS BY PERFORMING TESTS ON THE LIQUID ABOVE THE PRECIPITATE, WHICH SHOWED THE PRESENCE OF UNREACTED IONS. WE FIGURED OUT WHEN A REAGENT BECAME LIMITING BY OBSERVING THE HEIGHT OF THE COCO₃ PRECIPITATE. AS WE CHANGED THE RATIOS OF THE REACTANTS, WE NOTICED THAT WHEN ONE REACTANT WAS IN EXCESS, THE AMOUNT OF PRECIPITATE STOPPED INCREASING ONCE THE LIMITING REAGENT WAS USED UP. THIS SHOWS THAT THE RATIO OF THE REACTANTS DOES AFFECT WHICH ONE IS LIMITING; IF THE REACTANTS AREN’T MIXED IN THE CORRECT 1:1 RATIO, THE ONE IN THE SMALLER AMOUNT WILL LIMIT THE REACTION. THEORETICAL YIELD IS THE MAXIMUM AMOUNT OF PRODUCT WE CAN EXPECT FROM THE REACTION BASED ON CALCULATIONS FROM THE BALANCED EQUATION. PERCENT YIELD, ON THE OTHER HAND, COMPARES THE ACTUAL AMOUNT OF PRODUCT WE OBTAINED TO THE THEORETICAL YIELD. WE CALCULATED THE THEORETICAL YIELD TO HAVE A STANDARD FOR MEASURING HOW WELL THE REACTION WENT. TO FIND THE EXPERIMENTAL YIELD, WE WOULD NEED TO MEASURE HOW MUCH COCO₃ WAS ACTUALLY FORMED AND COMPARE THAT TO THE THEORETICAL YIELD. IN CONCLUSION, THIS EXPERIMENT EFFECTIVELY SHOWED HOW COBALT CARBONATE IS FORMED AND HIGHLIGHTED THE IMPORTANCE OF IDENTIFYING LIMITING REAGENTS. OUR PREDICTIONS ABOUT WHICH REACTANT WOULD BE IN EXCESS WERE CONFIRMED, AND WE LEARNED THAT THE RATIOS OF THE REACTANTS PLAY A KEY ROLE IN DETERMINING THE LIMITING REAGENT. BY UNDERSTANDING THE DIFFERENCE BETWEEN THEORETICAL AND EXPERIMENTAL YIELDS, WE GAINED VALUABLE INSIGHT INTO THE EFFICIENCY OF OUR REACTION. OVERALL, THIS INVESTIGATION REINFORCED IMPORTANT CHEMISTRY CONCEPTS AND PROVIDED PRACTICAL SKILLS THAT WILL BE USEFUL IN FUTURE EXPERIMENTS.