Mastering the Chemistry Olympiad: Sample Questions and Answers for Competitors and Aspiring Olympians

Synthesis of Nylon

Question 1: What are the two main starting materials used in the synthesis of nylon in the experiment? Provide their chemical names and formulas.

Question 2: Describe the type of reaction that occurs when adipoyl chloride and hexamethylenediamine react to form nylon. What is the product of this reaction?

Question 3: Explain the significance of the numbers “6,10” in Nylon-6,10. What do these numbers represent in terms of the structure of the polymer?

Question 4: What properties make nylon a suitable material for applications such as clothing, carpets, and industrial uses?

Question 5: If a student wanted to modify the synthesis of nylon to create Nylon-6,6 instead of Nylon-6,10, what changes would need to be made in the starting materials? Provide a brief explanation.

Synthesis of Aspirin

Question 1: What are the two main reactants used in the synthesis of aspirin? Provide their chemical names and formulas.

Question 2: Why is it important to add a small amount of concentrated sulfuric acid during the synthesis of aspirin?

Question 3: What is the function of acetic anhydride in the aspirin synthesis reaction? Explain in simple terms.

Question 4: Describe one way to purify aspirin once it has been synthesized in the lab.

Question 5: If a student obtained a lower yield of aspirin than expected during the synthesis, what could be a possible reason for this outcome? Provide two possible reasons.

TLC (Thin Layer Chromatography) of Pigments from Spinach

Question 1: What is the purpose of mixing hexane and acetone while grinding the spinach?

Question 2: Why the spotting of samples is done using small capillary?

Question 3: Based on the experiment, how many pigments are present in the spinach sample? Explain your answer.

Question 4: Which spot is the most soluble? Justify your answer.

Question 5: What is the R_f value of the pigment which is the most polar?

Solubility Tests and Recrystallization

Question 1: Based on the experiment, describe the solubility of benzoic acid in cold toluene. Suggest the polarity of benzoic acid.

Question 2: Why is the reaction mixture agitated in a hot water bath?

Question 3: If toluene is changed to ethanol, what would you observe on the solubility of both solvents? Provide justification for your answer.

Question 4: How to recover dissolved benzoic acid from the experiment? Explain and justify the method briefly.

Question 5: Can you suggest the continuity of the experiment in order to collect the purified benzoic acid crystals?