1.
If the Rf value is the same it is possible that the two molecules are identical (not necessarily) because both compound are traveling the same distance in the particular solvent.
They might be a different molecule if the solvent is changed and hence the Rf value will be different.
2. Solvent carries the molecules up the plate, the particular solvent used will have a substantial effect on the retention factor value for the molecules.
The mixture of solvent can also have different effects depending on the proportion of each solvent.
The eluting power of the solvent increases with polarity:
3.
PIGMENTS | Role of Pigments in leaf |
1. Chlorophylls |
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2.Carotenes |
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3.Anthrocyanins |
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1. If two spots have identical Rf values, does that mean that they are the same...
6.) a. Two compounds have the same Rf (0.74) under identical conditions. Does it mean that they have identical structures? Explain. b. On the basis of chemical structures, briefly explain why xanthophylls are more polar than carotenes, and chlorophylls more polar than pheophytins. c. Which compounds do you expect would have a larger Rf value, carotenes or xanthophylls? d. Arange the following compunds in order of increasing polarity: lutein, neoxanthin, -carotene, violaxanthin? e. Do you think that the hexanes extract...
Two compounds might have spots with the same Rf value in a TLC experiment and not be identical compounds. Which proposed TLC experiment could best help determine whether the compounds are identical? Select one: Repeat the original experiment with a mixture of the compounds in a single spot Repeat the original experiment with larger spots of each compound Repeat the original experiment with a different solvent system Repeat the original experiment with the development chamber jar open
1. Two compounds have the same Rf (0.87) under identical conditions. Does this show that they have identical structures? Why or why not? If not, what additional experiments would you perform? 2. Why can there be no breaks in the thin-layer surface of a TLC plate? 5. Write out the reaction between an organometallic reagent and acetone and use that to explain why these reactions must be kept dry (H20) and free of acetone.
2. If two different compounds have the same Rr value, how might they be identified using paper chromatography? 3. Why is it important to keep the spots on the paper as small as possible? 4. If the solvent pool at the bottom of the beaker touched the spots on the 1.5cm line, what would happen to the spots? How would you address this error? 5. If you were teaching a student how to do paper chromatography, what three pieces of...
Solve 1.Define reactivity as it relates to a scientific experiment. Provide two specific examples of how reactivity might affect a naturalistic observation experiment. 2.Explain the difference between a non-experimental method and an experimental method. Include a description of how each method is performed and identify which type of validity is more associated with each one. 3.Define both qualitative data and quantitative data. Then, identify the purpose, the group who is studied, and the role of the researcher for each type...
e. 18 Test Your Knowledge MULTIPLE CHOICE: Choose the one best answer. 1. Each element has its own characteristic atom in which a. the atomic mass is constant. b. the atomic number is constant. c. the mass number is constant. d. Two of the above are correct. e. All of the above are correct. 2. Which of the following is not a trace element in the human body? a. iodine b. zinc c. iron d. calcium e. fluorine 3. A...
1. According to the paper, what does lactate dehydrogenase (LDH) do and what does it allow to happen within the myofiber? (5 points) 2. According to the paper, what is the major disadvantage of relying on glycolysis during high-intensity exercise? (5 points) 3. Using Figure 1 in the paper, briefly describe the different sources of ATP production at 50% versus 90% AND explain whether you believe this depiction of ATP production applies to a Type IIX myofiber in a human....
First, read the article on "The Delphi Method for Graduate Research." ------ Article is posted below Include each of the following in your answer (if applicable – explain in a paragraph) Research problem: what do you want to solve using Delphi? Sample: who will participate and why? (answer in 5 -10 sentences) Round one questionnaire: include 5 hypothetical questions you would like to ask Discuss: what are possible outcomes of the findings from your study? Hint: this is the conclusion....
Using the book, write another paragraph or two: write 170 words: Q: Compare the assumptions of physician-centered and collaborative communication. How is the caregiver’s role different in each model? How is the patient’s role different? Answer: Physical-centered communication involves the specialists taking control of the conversation. They decide on the topics of discussion and when to end the process. The patient responds to the issues raised by the caregiver and acts accordingly. On the other hand, Collaborative communication involves a...
(1) State the type of research design used in the Schultz et al. report. (2) State the elements or characteristics of this type of design used in the Schultz report (see textbook for designs). (3) Does the research design fit with the research purpose? Provide rationale as to why or why not. (4) What is the dependent variable and independent variable? (5) Is there a conceptual model/framework described in the report? If yes, describe briefly in a few sentences the...