Nursing Elites

1. Water is capable of dissolving many substances that organisms need to carry out life functions. Which of the properties of water listed below is responsible for its ability to dissolve important nutrients like ionic salt compounds?

• A. adhesion
• B. cohesion
• C. high specific heat
• D. high polarity

Correct answer: D

Rationale: The property of water that is responsible for its ability to dissolve important nutrients like ionic salt compounds is its high polarity. Water is a polar molecule with a positive and negative end, which allows it to attract and surround individual ions from salt compounds, causing them to dissociate and dissolve in water. This property makes water an excellent solvent for various substances necessary for life functions. Adhesion refers to the ability of water molecules to stick to other substances, cohesion is the attraction between water molecules themselves, and high specific heat is the amount of heat energy required to raise the temperature of water. While these properties are important characteristics of water, they are not directly responsible for its ability to dissolve ionic salt compounds.

2. Balance the following redox reaction in acidic solution: I⁻ (aq) + Cr₂O₇²⁻ (aq) -> I₂ (aq) + Cr³⁺ (aq). Identify the oxidizing agent and reducing agent.

• A. I⁻ is oxidized, Cr₂O₇²⁻ is reduced
• B. I⁻ is reduced, Cr₂O₇²⁻ is oxidized
• C. Both I⁻ and Cr₂O₇²⁻ are oxidized
• D. Both I⁻ and Cr₂O₇²⁻ are reduced

Correct answer: B

Rationale: In the given redox reaction, I⁻ is gaining electrons to form I₂, which means I⁻ is being reduced (undergoing reduction). On the other hand, Cr₂O₇²⁻ is losing electrons to form Cr³⁺, indicating that Cr₂O₇²⁻ is being oxidized (undergoing oxidation). Therefore, I⁻ is the reducing agent and Cr₂O₇²⁻ is the oxidizing agent. Choice A is incorrect because I⁻ is being reduced, not oxidized. Choice C is incorrect as both species cannot be oxidized in the same reaction. Choice D is incorrect as both species cannot be reduced in the same reaction.

3. What is the scientific term for the involuntary rhythmic contraction and relaxation of the heart muscle?

• A. Peristalsis
• B. Myogenesis
• C. Myocardial contractility
• D. Systole and diastole

Correct answer: D

Rationale: The correct answer is D: Systole and diastole. Systole and diastole are the two phases of the cardiac cycle where the heart muscle contracts (systole) and relaxes (diastole) rhythmically to pump blood throughout the body. This rhythmic process ensures proper blood circulation by pumping blood to the lungs and the rest of the body. Peristalsis, on the other hand, refers to the involuntary constriction and relaxation of the muscles in the gastrointestinal tract, aiding in the movement of food and waste. Myogenesis is the process of muscle tissue formation, and myocardial contractility pertains to the heart muscle's ability to contract efficiently.

4. What does antidiuretic hormone (ADH) help the kidneys regulate?

• A. Acid-base balance
• B. Blood pressure
• C. Urine output by controlling water reabsorption
• D. All of the above

Correct answer: C

Rationale: Antidiuretic hormone (ADH) helps the kidneys regulate urine output by controlling water reabsorption. ADH acts on the kidneys to increase the reabsorption of water, leading to a decrease in urine output. This helps the body conserve water and maintain proper fluid balance. ADH primarily affects urine output by controlling water reabsorption and does not directly regulate acid-base balance or blood pressure. Therefore, choices A and B are incorrect because ADH does not directly influence acid-base balance or blood pressure.

5. What is the primary factor that determines whether a solute will dissolve in a solvent?

• A. Temperature
• B. Pressure
• C. Molecular structure
• D. Particle size

Correct answer: C

Rationale: The primary factor that determines whether a solute will dissolve in a solvent is the molecular structure. The compatibility of the solute's molecules with the solvent's molecules is crucial for dissolution to occur. While temperature, pressure, and particle size can influence the rate of dissolution, they are not the primary factors determining solubility. Molecular structure plays a key role in determining if a solute will form favorable interactions with the solvent, which is essential for dissolution to take place effectively. Temperature can affect solubility by changing the kinetic energy of molecules, pressure typically has a minor effect on solubility except for gases, and particle size influences the rate of dissolution by increasing surface area, but none of these factors are as fundamentally important as molecular structure in determining solubility.

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