Nursing Elites

1. In an SN2 reaction, what affects the rate of the reaction?

• A. Only the concentration of the nucleophile
• B. Only the concentration of the electrophile
• C. Neither the concentration of the nucleophile nor the electrophile
• D. Both the concentration of the nucleophile and the electrophile

Correct answer: D

Rationale: In an SN2 reaction, the rate of the reaction is affected by both the concentration of the nucleophile and the electrophile. The rate-determining step involves the nucleophile attacking the electrophile, so the concentrations of both species will impact the reaction rate. Increasing the concentration of the nucleophile increases the frequency of nucleophilic attacks, while increasing the concentration of the electrophile provides more opportunities for the nucleophile to react. Therefore, the correct answer is that both the concentration of the nucleophile and the electrophile affect the rate of the SN2 reaction. Choices A, B, and C are incorrect as they do not consider the interplay between the nucleophile and the electrophile in determining the overall reaction rate in an SN2 mechanism.

2. The framework of bones, cartilage, ligaments, and tendons that provides structure, support, and facilitates movement is part of the:

• A. Muscular system
• B. Skeletal system
• C. Nervous system
• D. Endocrine system

Correct answer: B

Rationale: The skeletal system consists of bones, cartilage, ligaments, and tendons that work together to provide structure, support, protection for internal organs, and facilitate movement. It is responsible for supporting the body's framework and protecting vital organs. The muscular system (option A) consists of muscles that work with the skeletal system to produce movement but does not include bones, cartilage, ligaments, and tendons. The nervous system (option C) is responsible for transmitting signals throughout the body to control movement and other functions. The endocrine system (option D) is a collection of glands that produce hormones to regulate various bodily functions but is not primarily involved in structure, support, and movement as the skeletal system is.

3. Why is the electrical conductivity of a strong acid solution higher than that of a weak acid solution?

• A. Strong acids are more concentrated.
• B. Strong acids release more hydrogen ions.
• C. Weak acids are better at dissolving salts.
• D. Strong acids have a lower pH.

Correct answer: B

Rationale: The correct answer is B because strong acids release more hydrogen ions compared to weak acids. This higher concentration of ions in the solution leads to a higher electrical conductivity. Strong acids ionize completely in solution, producing a higher concentration of ions that can conduct electricity, whereas weak acids only partially ionize, resulting in a lower concentration of ions and lower electrical conductivity. Choice A is incorrect because the concentration of the acid does not directly determine its electrical conductivity. Choice C is incorrect as the ability to dissolve salts is not directly related to electrical conductivity. Choice D is incorrect because the pH of the solution, although related to acidity, does not directly determine the electrical conductivity.

4. Where does gas exchange occur in the human body?

• A. Alveoli
• B. Bronchi
• C. Larynx
• D. Pharynx

Correct answer: A

Rationale: The correct answer is A: Alveoli. Gas exchange occurs in the alveoli, which are tiny air sacs in the lungs. Oxygen from the air we breathe diffuses into the blood vessels surrounding the alveoli, while carbon dioxide from the blood diffuses into the alveoli to be exhaled. The bronchi, larynx, and pharynx are all part of the respiratory system but are not directly involved in gas exchange. The bronchi are airways that lead to the lungs, the larynx is the voice box, and the pharynx is the throat. These structures are important for breathing and vocalization but do not participate in the exchange of gases between the respiratory system and the circulatory system.

5. Chromatids divide into identical chromosomes and migrate to opposite ends of the cell in which of the following phases of mitosis?

• A. metaphase
• B. anaphase
• C. prophase
• D. telophase

Correct answer: B

Rationale: During anaphase of mitosis, the sister chromatids detach from each other and migrate to opposite poles of the cell. This process ensures that each daughter cell ultimately receives an identical set of chromosomes, as the chromatids separate and become individual chromosomes again. This is a crucial step in ensuring accurate distribution of genetic material during cell division. In metaphase, the chromosomes align at the cell's equator but do not separate yet. Prophase is the phase where chromatin condenses into chromosomes and the nuclear envelope breaks down. Telophase is the final phase where the nuclear envelope reforms around the separated chromosomes.

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