Question

In the reducing sugar exercise, why do you think the time that the samples are in the hot water bath not exceed two minutes? In the starch exercise, why must you shake the positive control and each of the unknowns before taking a sample of each? 2. 3. What structure, within proteins, does the biuret reagent actually react with when it gets reduced giving positive result? 4. Now that you have completed all chemical tests, you probably have more of a sense why positive and negative controls are so important for qualitative measures. Explain below at least two reasons why positive and negative controls are so important. 5. Chemical tests, very much like the ones performed here, are routinely performed on unknown liquids and powders discovered at crime scenes. Do you think that crime labs also use positive and negative controls? Why or why not? 6 Continulng from the above question... Crime labs also tend to repeat tests several times, even if the answer is clear and obvious the first time. Why do you suppose this is? 7. In today's lab you used two tests to identify the presence of lipids, which is called "independent verification". Explain why this would be important. What is the risk you run if independent verification isn't carried out when testing unknowns? Lab #3-Page 12

plz try to give all the answers.

Answer 1

I will give you answer for first question and rest will be answered by other exeprts.

1. The sample in hot water bath not exceeds two minutes because there can be possibilities of false positive from other water soluble compound might react if left longer than two minutes.

Hope the answer is clear!! Please give positive feedback! Thank you