Nursing Elites

1. 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: The balanced chemical equation indicates that 2 moles of sodium react with 2 moles of water to yield 2 moles of sodium hydroxide and 1 mole of hydrogen gas. When 3 moles of sodium react with only 2 moles of water, sodium becomes the limiting reactant as it is present in excess compared to the available water molecules. This situation arises because not all sodium atoms can fully react with the limited amount of water, resulting in sodium being the limiting reactant in this specific case. Choice B (H2O), choice C (NaOH), and choice D (H2) are incorrect as they are not the limiting reactant in the given reaction scenario.

2. Which type of joint allows for the most movement?

• A. Ball-and-socket joint (shoulder)
• B. Hinge joint (elbow)
• C. Fibrocartilaginous joint (wrists)
• D. Suture joint (skull)

Correct answer: A

Rationale: A ball-and-socket joint allows for the most movement among the options provided. This type of joint is characterized by a rounded end of one bone fitting into a cup-like socket of another bone, allowing for a wide range of motion in multiple directions. The shoulder joint is a prime example of a ball-and-socket joint, enabling movements such as flexion, extension, abduction, adduction, and rotation. In contrast, a hinge joint (option B) like the elbow primarily allows for movement in one plane (flexion and extension). Fibrocartilaginous joints (option C) like the wrists have limited movement due to the presence of cartilage between the bones. Suture joints (option D) in the skull are immovable joints that provide structural support but do not allow for significant movement.

3. Which type of blood vessel carries blood away from the heart?

• A. Vein
• B. Artery
• C. Capillary
• D. Venule

Correct answer: B

Rationale: The correct answer is B: Artery. Arteries carry oxygen-rich blood away from the heart to various parts of the body. Veins, on the other hand, carry blood back to the heart. Capillaries are tiny blood vessels where oxygen and nutrients are exchanged with tissues. Venules are small veins that collect blood from capillaries, not from the heart, making them incorrect in this context.

4. Which of the following nerves has the longest axon in the human body?

• A. Dorsal root ganglion
• B. Laryngeal nerve
• C. Sciatic nerve
• D. None of the above

Correct answer: C

Rationale: The sciatic nerve contains the longest axon in the human body, extending from the lower back down the leg. This nerve is responsible for innervating the muscles of the lower limb. The dorsal root ganglion and laryngeal nerve do not possess axons as long as the sciatic nerve, making them incorrect choices. Therefore, the correct answer is C, the sciatic nerve.

5. Which of the following is a type of white blood cell that plays a key role in adaptive immunity by seeking out, attacking, and destroying targeted pathogens?

• A. memory B cells
• B. neutrophils
• C. antibodies
• D. cytotoxic T cells

Correct answer: D

Rationale: The correct answer is cytotoxic T cells. Cytotoxic T cells are a type of white blood cell that is crucial in adaptive immunity. They are specialized in recognizing and destroying infected or abnormal cells in the body. Neutrophils are primarily involved in innate immunity, providing rapid response to infections. Antibodies are proteins produced by B cells and are essential in specific immune responses, but they do not directly attack pathogens. Memory B cells are part of the adaptive immune response, responsible for mounting a quicker and stronger response upon re-exposure to a pathogen. However, they do not directly seek out and destroy pathogens like cytotoxic T cells do.

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