Nursing Elites

1. When is a solution formed?

• A. One substance dissolves in another
• B. Two or more substances react chemically
• C. A solid changes to a liquid
• D. None of the above

Correct answer: A

Rationale: A solution is formed when one substance dissolves in another. This process creates a homogeneous mixture where the solute is dispersed in the solvent, resulting in a uniform composition throughout the mixture. Choice B is incorrect because chemical reactions involve the transformation of substances into new compounds, not the formation of solutions. Choice C is incorrect as it describes a physical change from a solid to a liquid, not the formation of a solution. Choice D is incorrect as one substance dissolving in another is the defining characteristic of a solution.

2. Which statement is true about the pH of a solution?

• A. A solution cannot have a pH less than 0.
• B. A solution always has a pH of 7.
• C. A solution's pH is not influenced by its chemical composition.
• D. A solution with a pH of 14 is considered acidic.

Correct answer: A

Rationale: The pH scale ranges from 0 to 14, with 0 being the most acidic, 7 neutral, and 14 the most basic. A solution with a pH less than 0 would be outside the defined pH range, as 0 is the lower limit. Therefore, a solution cannot have a pH less than 0. Choice B is incorrect because a pH of 7 is considered neutral, not always the pH of a solution. Choice C is incorrect because a solution's pH is influenced by its chemical composition. Choice D is incorrect as a solution with a pH of 14 is considered highly basic, not acidic.

3. What condition is characterized by progressive muscle weakness and wasting?

• A. Muscular dystrophy
• B. Myositis
• C. Fibromyalgia
• D. Carpal tunnel syndrome

Correct answer: A

Rationale: Muscular dystrophy is a genetic disorder characterized by progressive muscle weakness and wasting due to mutations in genes responsible for muscle cells' structure and function. Myositis is an inflammatory muscle disease, fibromyalgia is a chronic pain condition, and carpal tunnel syndrome affects the hand and arm nerves, but none present with the progressive muscle weakness and wasting seen in muscular dystrophy.

4. What is the role of hemoglobin in the human body?

• A. Transport oxygen in red blood cells
• B. Bind oxygen to red blood cells
• C. Carry carbon dioxide from tissues to lungs
• D. Help red blood cells transport oxygen

Correct answer: D

Rationale: The correct answer is D: 'Help red blood cells transport oxygen.' Hemoglobin acts as a carrier molecule in red blood cells, binding to oxygen in the lungs and releasing it in the tissues. It facilitates the transport of oxygen from the lungs to the tissues and aids in returning carbon dioxide from the tissues to the lungs. Choices A, B, and C are incorrect because hemoglobin itself does not transport oxygen independently or bind oxygen to red blood cells nor does it carry carbon dioxide from tissues to lungs; instead, it assists red blood cells in the transportation of oxygen.

5. Which feedback loops are less common and sometimes harmful because they enhance stimuli rather than inhibit them?

• A. Negative feedback loop
• B. Positive feedback loop
• C. Inhibitory feedback loop
• D. Stimulating feedback loop

Correct answer: B

Rationale: Correct. Positive feedback loops enhance or amplify changes, which can sometimes be harmful as they drive processes further from equilibrium. In contrast, negative feedback loops work to counteract deviations from a set point, promoting stability. Choice A, 'Negative feedback loop,' is incorrect because negative feedback loops inhibit or reduce changes, promoting stability. Choice C, 'Inhibitory feedback loop,' is incorrect as it is synonymous with negative feedback loops. Choice D, 'Stimulating feedback loop,' is incorrect as it inaccurately describes the nature of positive feedback loops.

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