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. How does an increase in surface area affect the force of friction between two surfaces?

• A. Increases friction
• B. Decreases friction
• C. Has no effect on friction
• D. Causes unpredictable changes in friction

Correct answer: A

Rationale: An increase in surface area typically increases the force of friction between two surfaces. This is because with a larger surface area in contact, there are more points of contact between the surfaces, leading to a greater frictional force resisting motion. As a result, the correct answer is that an increase in surface area increases the force of friction between two surfaces. Choice B is incorrect because a greater surface area increases the frictional force. Choice C is incorrect because an increase in surface area results in more contact points and greater friction. Choice D is incorrect as the relationship between surface area and friction is predictable - an increase in surface area generally leads to an increase in frictional force.

3. Which part of the brain is responsible for memory and learning?

• A. Cerebellum
• B. Cerebrum
• C. Medulla oblongata
• D. Brainstem

Correct answer: B

Rationale: The correct answer is B - Cerebrum. The cerebrum, not the cerebellum as in choice A, is the largest part of the brain and is responsible for memory, learning, and higher cognitive functions. It processes sensory information, enables reasoning, and decision-making, all crucial for memory formation and learning processes. Choices C and D, Medulla oblongata and Brainstem respectively, do not primarily play roles in memory and learning processes. The Medulla oblongata is mainly involved in regulating vital autonomic functions like breathing and heart rate, while the Brainstem serves as a pathway for neural communication and houses essential control centers for basic life functions, not memory and learning.

4. What are the white blood cells responsible for coordinating the immune response called?

• A. Red blood cells
• B. Platelets
• C. Lymphocytes
• D. Neutrophils

Correct answer: C

Rationale: Lymphocytes, which include B cells, T cells, and natural killer cells, are responsible for coordinating the immune response. They play a crucial role in recognizing and fighting against pathogens and foreign substances in the body. Red blood cells are responsible for oxygen transport, platelets aid in blood clotting, and neutrophils are white blood cells primarily involved in combating infections. Therefore, the correct answer is C, lymphocytes, as they are specifically involved in coordinating immune responses.

5. What is the sensory threshold?

• A. The smallest amount of stimulus required for an individual to feel a sensation
• B. The amount of stimulus required for an individual to feel pain
• C. The amount of stimulus required to cause an individual to move away from the stimulus
• D. The place from which the stimulus is coming

Correct answer: A

Rationale: The sensory threshold refers to the smallest amount of stimulus required for an individual to perceive or feel a sensation. It is the minimum level of stimulus intensity that is detectable by an individual. Choice B is incorrect because the sensory threshold is not specifically related to feeling pain but rather to perceiving any sensation. Choice C is incorrect as the sensory threshold is about perception and not necessarily physical reaction. Choice D is incorrect as it describes the source of the stimulus, not the threshold for perception.

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