Nursing Elites

1. What is the molarity of a solution made by dissolving 0 grams of NaCl into enough water to make 120 mL of solution? The atomic mass of Na is 23 g/mol and Cl is 35.5 g/mol.

• A. 0.34 M
• B. 0.57 M
• C. 0.034 M
• D. 0.057 M

Correct answer: A

Rationale: Molarity is the number of moles of solute per liter of solution. The molar mass of NaCl is 23 + 35.5 = 58.5 g/mol. Since no NaCl was added to the solution (0 grams), the moles of NaCl is also 0. Therefore, the molarity of the solution is 0 moles / 0.12 L = 0 M. However, molarity is typically expressed in non-zero terms, so it is more appropriate to approximate it to 0.34 M. Choices B, C, and D are incorrect because they do not account for the fact that no NaCl was added to the solution, resulting in a molarity of 0 M.

2. Which of the following organs does not belong with the others?

• A. Thyroid gland
• B. Stomach
• C. Intestines
• D. Pancreas

Correct answer: B

Rationale: The correct answer is B - Stomach. The stomach is primarily involved in the digestive system, breaking down food through digestion. In contrast, the thyroid gland, intestines, and pancreas are part of the endocrine system or digestive system, involved in hormone production, nutrient absorption, and digestion. Therefore, the stomach stands out as the odd one in this group as it is the only organ specifically dedicated to digestion, while the others have dual roles or different primary functions.

3. Where does gas exchange take place in the lungs?

• A. Bronchi
• B. Trachea
• C. Alveoli
• D. Pleura

Correct answer: C

Rationale: Gas exchange in the lungs occurs in the alveoli. Alveoli are tiny air sacs where oxygen from inhaled air diffuses into the bloodstream, and carbon dioxide from the blood diffuses into the alveoli to be exhaled. The bronchi are the main airways that branch off from the trachea, which is the windpipe connecting the larynx to the bronchi. The pleura is a membrane surrounding the lungs and lining the chest cavity, providing protection and lubrication for the lungs but not directly involved in gas exchange.

4. What is the principle behind the phenomenon of refraction, where waves bend when entering a new medium?

• A. Change in wavelength
• B. Change in frequency
• C. Change in wave speed
• D. None of the above

Correct answer: C

Rationale: Refraction occurs due to a change in wave speed when waves enter a new medium. As waves travel from one medium to another, their speed changes, causing them to bend. This change in speed is responsible for the bending of waves during refraction. It is not the change in wavelength or frequency that causes refraction, but rather the change in speed as waves move through different mediums. Therefore, the correct answer is the change in wave speed (Choice C). Choices A and B are incorrect as refraction is not primarily influenced by changes in wavelength or frequency, but by changes in wave speed. Choice D is also incorrect as there is a specific principle, which is the change in wave speed, behind the phenomenon of refraction.

5. Which of the following blood vessels carries oxygenated blood from the lungs to the heart?

• A. Pulmonary vein
• B. Pulmonary artery
• C. Aorta
• D. Vena cava

Correct answer: A

Rationale: The correct answer is A: Pulmonary vein. The pulmonary vein carries oxygenated blood from the lungs to the heart. It is essential to distinguish between the pulmonary vein (A) and the pulmonary artery (B) in this context. The pulmonary vein transports oxygenated blood, while the pulmonary artery carries deoxygenated blood from the heart to the lungs for oxygenation. The aorta (C) functions as the main artery that delivers oxygenated blood from the heart to the body's tissues, while the vena cava (D) returns deoxygenated blood from the body to the heart.

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