Nursing Elites

1. Entropy (S) is a thermodynamic property related to the system's disorder. According to the second law of thermodynamics, in a spontaneous process:

• A. The total entropy of the system and surroundings increases.
• B. The total entropy of the system and surroundings decreases.
• C. The total entropy of the system remains constant.
• D. The total entropy of the surroundings increases, while the system's entropy decreases.

Correct answer: A

Rationale: Entropy is a measure of a system's disorder or randomness. According to the second law of thermodynamics, in a spontaneous process, the total entropy of the system and surroundings increases, leading to a higher level of disorder or randomness. This increase in total entropy is consistent with the idea that systems tend towards higher entropy states over time. Therefore, option A is correct because it aligns with the principle that the total entropy of a closed system, including both the system and its surroundings, will increase in a spontaneous process.

2. What is the main function of valence electrons in chemical bonding?

• A. They are responsible for holding the nucleus together.
• B. They are involved in forming bonds with other atoms.
• C. They determine the element's physical properties.
• D. They play no role in chemical reactions.

Correct answer: B

Rationale: They are involved in forming bonds with other atoms. Valence electrons occupy the outermost energy level and are readily involved in attracting other atoms through sharing or transferring electrons, forming chemical bonds.

3. What is the myelin sheath and what does it do?

• A. A group of nerve cells that perform a specific function.
• B. A fatty substance that insulates some nerve fibers.
• C. A fluid-filled cavity within the brain.
• D. The junction between two neurons.

Correct answer: B

Rationale: The correct answer is B. The myelin sheath is a fatty substance that insulates some nerve fibers. It is essential for the proper functioning of the nervous system as it acts as an insulator, allowing for faster transmission of nerve impulses along the axon. Without the myelin sheath, nerve signals could be disrupted or weakened, leading to issues with movement, sensation, and other neurological functions. Options A, C, and D are incorrect as they do not accurately describe the myelin sheath or its function.

4. What is the primary factor that determines whether a solute will dissolve in a solvent?

• A. Temperature
• B. Pressure
• C. Molecular structure
• D. Particle size

Correct answer: c

Rationale: The molecular structure of the solute and solvent plays a key role in determining solubility. The other choices may influence solubility but are not the primary determining factor.

5. Scientists compare the DNA of different organisms to understand evolutionary relationships. What is this type of evidence called?

• A. Morphological evidence (comparing body structures)
• B. Biochemical evidence (comparing molecules like proteins)
• C. Geographic distribution evidence (where organisms live)
• D. Genetic evidence (comparing DNA sequences)

Correct answer: D

Rationale: Rationale: A) Morphological evidence involves comparing body structures of organisms, which can provide information about evolutionary relationships based on physical similarities and differences. However, DNA comparison is a more direct and accurate method for understanding evolutionary relationships. B) Biochemical evidence involves comparing molecules like proteins, which can also provide insights into evolutionary relationships. However, DNA comparison is considered more reliable due to the direct relationship between DNA sequences and genetic information. C) Geographic distribution evidence refers to where organisms live and how their distribution may provide clues about evolutionary history. While this can be informative, it is not as direct or specific as comparing DNA sequences. D) Genetic evidence involves comparing DNA sequences of different organisms to understand their evolutionary relationships. DNA comparison is a powerful tool in evolutionary biology because it provides

6. In the reaction 2Na + 2H2O → 2NaOH + H2, what is the limiting reactant when 3 moles of sodium react with 2 moles of water?

• A. Na
• B. H2O
• C. NaOH
• D. H2

Correct answer: a

Rationale: Sodium is the limiting reactant because it runs out first in a 1:1 ratio with water.

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