Chemistry Please answer the following: 1. Which is the key to the success of this experiment? A. Extraction of caffeine B. Rotation and evaporation C. Sublimation D. Infrared tableting process of the solid 2. Which of the following heterocyclic structures are present in the caffeine structure? A. Pyrimidine B. imidazole C. Indole D. Pyridine 3. The advantages of Soxhlet extractor? A. Save solvent. B. High extraction efficiency. C. The experiment time is short. D. Low instrument cost. 4. During the extraction of Caffeine From Tea leaves, what is the purpose of adding quick lime?

(29) Two B-vitamins are shown below. Examine their structures in order to answer the related questions. но но но он H3C HO но NH H- CH3 Vitamin B5 NH H3C Pantothenic acid Vitamin B, Riboflavin a. Do one or both contain aromatic rings? Which one(s)? b. What is the longest straight carbon chain in either vitamin? c. Write the chemical formula for each vitamin. d. Would you consider these vitamins to be water-soluble or lipid-soluble? What characteristics or features support your answer? e. Does your answer to the previous question agree with the following information? Vitamins Bs and B2 are known to be more easily expelled in urine and so they need to be more frequently consumed in the diet or through supplements, unlike with vitamins A, D, E and K.

Match the four samples below, to their correct designation (either pure substances or mixures) v R-(-)-Carvone v spearmint oil A. pure substance B. mixture S-(+)-Carvone caraway oil

What is the form of free chlorine in water disinfection using chlorination? Group of answer choices A. HOCl B. OCl- C. Cl2 D. HOCl + OCl-