Nursing Elites

1. What causes varicose veins to occur?

• A. Atherosclerosis.
• B. Incompetent valves.
• C. Loss of skin turgor.
• D. Loss of blood vessel elasticity.

Correct answer: B

Rationale: Varicose veins occur when the valves within the veins become incompetent, leading to blood pooling in the veins instead of being efficiently pumped back to the heart. This causes the veins to become enlarged, twisted, and visible under the skin. Factors such as genetics, aging, pregnancy, and prolonged standing or sitting can contribute to the development of incompetent valves and the resulting varicose veins. Atherosclerosis is the buildup of plaque in arteries, not veins, and does not directly cause varicose veins. Loss of skin turgor is related to skin elasticity and not a direct cause of varicose veins. Loss of blood vessel elasticity is a general term and does not specifically address the mechanism behind varicose veins, which is primarily due to incompetent valves.

2. Which structure protects the lungs?

• A. Femur
• B. Ribcage
• C. Scapula
• D. Skull

Correct answer: B

Rationale: The ribcage is the correct answer. It protects the lungs by providing structural support and shielding them from injury. The femur is a bone in the thigh and does not protect the lungs. The scapula is a shoulder blade bone, and the skull protects the brain, not the lungs.

3. Which part of the respiratory system is responsible for gas exchange between the blood and inhaled air?

• A. Trachea
• B. Larynx
• C. Alveoli
• D. Pharynx

Correct answer: C

Rationale: The correct answer is C, Alveoli. The alveoli are tiny air sacs in the lungs where the exchange of oxygen and carbon dioxide takes place between the air we breathe in and the blood. The trachea, larynx, and pharynx are all part of the airway passage but do not directly participate in gas exchange. The trachea serves as the windpipe, the larynx is involved in sound production and protecting the airway during swallowing, and the pharynx helps with swallowing and speech production. Therefore, the alveoli specifically facilitate the critical gas exchange process, making them the correct answer in this context.

4. How many mL of a 0 M stock solution of HCl should be added to water to create 250 mL of a 50 M solution of HCl?

• A. 31.25 mL
• B. 32 mL
• C. 30 mL
• D. 31.3 mL

Correct answer: B

Rationale: To prepare 250 mL of a 50 M solution of HCl, the formula V1 x C1 = V2 x C2 is used, where V1 is the volume of the stock solution, C1 is the concentration of the stock solution, V2 is the final volume of the desired solution, and C2 is the final concentration of the desired solution. Given V1 x 0 M = 250 mL x 50 M, solving for V1 results in V1 = (250 mL x 50 M) / 0 M = 32 mL. Therefore, 32 mL of the 0 M stock solution of HCl needs to be added to water to create a 250 mL solution of 50 M HCl. Choices A, C, and D are incorrect because they do not represent the accurate volume required for the dilution calculation based on the given concentrations and volumes in the problem.

5. What does the term 'solute' refer to in a solution?

• A. The substance present in the largest amount
• B. The substance that dissolves in the solvent
• C. The liquid portion of the solution
• D. The temperature at which the solution freezes

Correct answer: B

Rationale: In a solution, the term 'solute' specifically refers to the substance that dissolves in the solvent to create a solution. The solute is typically present in a smaller amount compared to the solvent. Option B correctly identifies the solute as the substance that undergoes dissolution in the solvent, making it the correct choice. Choices A, C, and D are incorrect. Choice A is actually describing the solvent, which is the substance present in the largest amount in a solution. Choice C refers to the solvent, not the solute. Choice D is unrelated to the term 'solute' as it describes the colligative property of freezing point depression, not the solute itself.

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