Extraction and Purification of Caffeine from Tea Leaves: Experiments 7(A) and 7(B), Lab Reports of Chemistry

Download Extraction and Purification of Caffeine from Tea Leaves: Experiments 7(A) and 7(B) and more Lab Reports Chemistry in PDF only on Docsity! CHEM 14CL FALL 2000 7(A)&7(B) - EXTRACTION AND PURIFICATION OF CAFFEINE FROM TEA LEAVES Procedures for experiment 7(A) - see p.76 - 80 (lab manual) Procedures for experiment 7(B) - see p. 82- 89 (lab manual) PRELAB FOR 7(A) 1. Introduction 2. Prepare a flow chart of procedures AND show the location of the caffeine throughout each step of the experiment in the flow chart. (Hint: See the end of Expt 8 in Landgrebe). Make sure you also REFERENCE the procedures. NOTE: Make sure that you look for organization of ideas and not just a copy of the procedure in boxes. 3. Questions 1,7,8,10,11 in Landgrebe (see page 140-141) (MUST SHOW ALL WORK FOR FULL CREDIT). Note: Kp is equivalent to α (see lecture guide for definition). NOTE: There is NO prelab for experiment 7(B) POSTLAB REPORT - 7(A) THIS IS AN INDIVIDUAL REPORT (i) Record all observations. (ii) Use equations to help explain any chemical reactions.or explain the phenomenon (physical changes)behind each of your other observations. (iii) Calculate the % caffeine that you recovered from tea. (iv) Compare your % caffeine value to the reported value of caffeine content in tea leaves in Landgrebe (see page. 380 - 381). Explain any differences. (v) Compare experimental IR spectrum to literature IR spectrum (provided with the 7(B) worksheets). What can you conclude about the purity of your product. (vi) Mass Spectrum of caffeine: (i) identify the base peak. (ii) identify the molecular ion peak. (iii) is the molecular ion peak the same as the base peak in the spectrum? POSTLAB REPORT - 7(B) IS FOR THE “INFRARED SPECTROSCOPY EXPERIMENT”. THIS IS A GROUP REPORT. (I) Completed IR worksheets for the 5 molecules. The 5 molecules are: 2 different carbon dioxide; acetic acid; propionamide and allyl benzoate.