Pre-lab Report for Colorimetic Analysis for the Iron Oxalate ComplexColorimetric Analysis of Iron (Refer to Lab Schedule for Due Date)Colorimetric Analysis of IronCHEM 30AL Spring 2003 Experiment #11: Synthesis and Analysis of Iron oxalate (Part 3) Pre-lab Report for Colorimetic Analysis for the Iron Oxalate Complex There is NO Pre-lab Report for this part of the experiment. There will be an in-lab quiz instead. The quiz will include the concepts from experiment #11 (not just part 3 of the experiment). Review the lecture guides (and any assigned readings – refer to the lab schedule) as well as your previous pre-labs to prepare for the quiz. Review ALL the study questions on p.99 of the manual. The quiz is CLOSED book and notes. You may use a calculator during the quiz. You will have a maximum of 30 minutes to complete the quiz. The quiz will start 5 minutes after the start of the lab section. You will NOT receive extra time if you show up late to the lab. You must take the quiz in the lab section in which you are officially enrolled. There is no make up if you miss the quiz.CHEM 30AL Spring 2003 Experiment #11: Synthesis and Analysis of Iron oxalate (Part 3) Post-lab Report Guidelines for Iron Oxalate Experiment (Part 3) Colorimetric Analysis of Iron (Refer to Lab Schedule for Due Date) This is a GROUP report (i.e. ONE post-lab PER GROUP) (A) Abstract (refer to PART 1 post-lab guidelines for this experiment on how to write the abstract. In general, remember this format since those are the common materials that should be included in any abstract) (B) Data (see p.103 under Colorimetric Analysis) Write down the names of all the members in the group. Write out the responsibility of each member both for the experiment and for the postlab report. Data tables with all the experimental data (should have proper titles/labels) (C) Graph(s) Beer's Law calibration plot of absorbance vs. concentration for all the standard solutions Your graph must have proper title, labels. Data points must be clearly marked. Make sure you use the correct type of graph paper. If you use EXCEL, make sure that the gridlines are set properly. (D) Data Analysis (MUST SHOW ALL WORK FOR FULL CREDIT) Refer to Week 1 Lecture guide and concepts from 20L for this part of the report. (1) Calculate the concentrations for all the standard solutions (2) From the Beer’s law calibration graph, calculate the slope of the calibration line (with proper unit) (indicate which two points on the line you use for calculating the slope or use EXCEL to find the slope of the best fit line.) (3) from the calculated slope of the line and the absorbance of “solution B”, determine the concentration of iron in the “solution B” (with proper unit) (4) Use the result from (3) to calculate the moles of iron/gram of product (5) Use the result from (4) to calculate the experimental molecular weight of your product (6) Calculate the ratio of moles of oxalate/grams of sample (from PART 2) and the moles of iron/grams of sample (your result from (4)). This gives you the number of oxalate in the complex. (7) Determine the number of potassium ions required to neutralize the charge in the complex base on your result from (6). Explain your reasonings. (8) Propose a molecular formula for the complex neutral salt that you prepared. Report guidelines continue on NEXT pageCHEM 30L Spring 2003 Experiment #11: Synthesis and Analysis of Iron oxalate (Part 3) Post-lab Report Guidelines for Iron Oxalate Experiment (Part 3) Colorimetric Analysis of Iron This is a GROUP report (E) Error Analysis (Refer to week 1 lecture guide as well as lecture guides FROM 20L for details on error analysis) Absolute uncertainties for various laboratory equipment are listed on page 31 of your lab manual (i) error in concentration for ONE of your standard solution (all terms identified and error bar placed on graph) (ii) error in absorbance for ONE of your standard solution (all terms identified and error bar placed on graph) (iii) calculate the range of slopes of standard line. You MUST show either mathematically how you obtain those slopes (i.e. max. slope and min. slope must be labeled clearly on your graph) (iv) error in absorbance of your “solution B” unknown (v) error in concentration of your “solution B” unknown (vi) Calculate the % inherent error for unknown solution B Note: If no error was given on the reagent bottle, you may assume the % relative error in the stock iron(II) sulfate solution is ± 1% If you use 1-ml plastic disposable syringe when preparing the standards, assume the absolute error in the syringe to be +/- 0.1mL. Use this syringe absolute error instead of the one listed on page 31 of the lab manual. (F) Conclusions (i) Calculate the % difference in your experimental molecular weight (the one for the compound you are proposing) with the theoretical molecular weight of the complex (i.e. the “expected” molecular weight) (ii) Discuss reasons for the differences in the two
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