Nursing Elites

1. How many moles of water are produced when 0.5 moles of methane (CH4) react with excess oxygen?

• A. 0.5 moles
• B. 1 mole
• C. 2 moles
• D. 3 moles

Correct answer: B

Rationale: The balanced chemical equation for the combustion of methane is: CH4 + 2O2 -> CO2 + 2H2O. This equation shows that 1 mole of methane produces 2 moles of water. Therefore, when 0.5 moles of methane react, they will produce 1 mole of water. The ratio of water to methane is 2:1, meaning that for every mole of methane that reacts, it produces 2 moles of water. Since only 0.5 moles of methane are reacting, the amount of water produced will be half of what would be produced if 1 mole of methane reacted, resulting in 1 mole of water being produced. Choice A is incorrect because it does not consider the stoichiometry of the reaction. Choices C and D are incorrect as they do not align with the balanced chemical equation and the stoichiometric ratios involved in the reaction.

2. What is the largest lymphatic vessel in the body responsible for draining lymph from most of the body called?

• A. Jugular vein
• B. Thoracic duct
• C. Subclavian vein
• D. Aorta

Correct answer: B

Rationale: The correct answer is B: Thoracic duct. The thoracic duct is the largest lymphatic vessel in the body and is responsible for draining lymph from most of the body. The jugular vein, subclavian vein, and aorta are not lymphatic vessels responsible for draining lymph. The jugular vein and subclavian vein are blood vessels, while the aorta is the main artery that carries oxygenated blood from the heart. Understanding the role and anatomy of the lymphatic system is crucial for comprehending the body's immune response and fluid balance.

3. During a healthy heartbeat, the P wave on an ECG represents

• A. The repolarization of the ventricles.
• B. The electrical conduction through the AV node.
• C. The contraction phase of the ventricles (systole).
• D. The depolarization of the atria.

Correct answer: D

Rationale: The P wave on an ECG represents the depolarization of the atria. This electrical activity initiates the contraction of the atria, allowing blood to be pumped into the ventricles. The P wave is the first positive deflection seen on the ECG and signifies the beginning of atrial depolarization, which is a critical step in the cardiac cycle. Choices A, B, and C are incorrect. Option A (The repolarization of the ventricles) is represented by the T wave on the ECG. Option B (The electrical conduction through the AV node) is not represented by the P wave but rather by the PR interval on the ECG. Option C (The contraction phase of the ventricles (systole)) is more related to the QRS complex on the ECG, which represents ventricular depolarization and contraction.

4. Which structure in the ear is responsible for maintaining balance?

• A. Cochlea
• B. Semicircular canals
• C. Eardrum
• D. Auditory nerve

Correct answer: B

Rationale: The correct answer is the semicircular canals. These structures in the inner ear are responsible for maintaining balance and equilibrium by detecting rotational movements of the head. The cochlea is responsible for hearing as it contains the sensory cells for detecting sound vibrations, the eardrum is a membrane that transmits sound waves to the middle ear, and the auditory nerve carries sound signals from the cochlea to the brain for processing. Therefore, choices A, C, and D are incorrect as they are not primarily associated with maintaining balance.

5. What is the function of the epiglottis?

• A. Produces saliva
• B. Senses taste
• C. Prevents food from entering the windpipe
• D. Filters blood

Correct answer: C

Rationale: The epiglottis is a flap of cartilage located at the base of the tongue that covers the opening of the windpipe (trachea) during swallowing to prevent food and liquids from entering the airway. This action ensures that food and liquids are directed to the esophagus and down into the stomach, rather than entering the respiratory system, which could lead to choking or aspiration pneumonia. Options A, B, and D are incorrect as they describe functions of other structures in the body that are not related to the role of the epiglottis.

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