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 of the following terms refers to the process of breaking large molecules into smaller molecules to provide energy?

• A. Metabolism
• B. Bioenergetics
• C. Anabolism
• D. Catabolism

Correct answer: D

Rationale: The correct answer is 'D: Catabolism.' Catabolism specifically involves breaking down large molecules into smaller ones to release energy. It is the opposite of anabolism, which is the process of building larger molecules from smaller ones. 'Metabolism' (choice A) is a broader term that encompasses all chemical processes in an organism, including anabolism and catabolism. 'Bioenergetics' (choice B) refers to the flow and transformation of energy in a biological system, not specifically the breakdown of molecules for energy.

3. Which of the following has a smaller genetic scale than a chromosome?

• A. Genome
• B. Gene
• C. DNA
• D. All of the above

Correct answer: B

Rationale: The correct answer is 'B: Gene.' A gene is a segment of DNA and is smaller in scale than a chromosome. Genes are the fundamental units of heredity, containing the instructions for building and maintaining an organism. While a chromosome is a larger structure that carries many genes, each gene is a specific segment of DNA responsible for encoding a particular protein or RNA molecule. Choices A, C, and D are incorrect. The 'Genome' (Choice A) refers to the complete set of an organism's genetic material, including all of its genes, while 'DNA' (Choice C) is the molecule that carries the genetic instructions. 'All of the above' (Choice D) is incorrect because not all options have a smaller genetic scale than a chromosome.

4. In the reaction 2Na + 2H2O → 2NaOH + H2, what is the limiting reactant when 3 moles of sodium react with 2 moles of water?

• A. Na
• B. H2O
• C. NaOH
• D. H2

Correct answer: A

Rationale: The balanced chemical equation indicates that 2 moles of sodium react with 2 moles of water to yield 2 moles of sodium hydroxide and 1 mole of hydrogen gas. When 3 moles of sodium react with only 2 moles of water, sodium becomes the limiting reactant as it is present in excess compared to the available water molecules. This situation arises because not all sodium atoms can fully react with the limited amount of water, resulting in sodium being the limiting reactant in this specific case. Choice B (H2O), choice C (NaOH), and choice D (H2) are incorrect as they are not the limiting reactant in the given reaction scenario.

5. What is the difference between exhalation (expiration) and inhalation (inspiration)?

• A. Exhalation involves active muscle contraction, while inhalation is passive.
• B. Inhalation brings in oxygen-rich air, while exhalation releases carbon dioxide-rich air.
• C. Exhalation occurs through the nose only, while inhalation can occur through the nose or mouth.
• D. Inhalation warms and humidifies air, while exhalation cools and dries air.

Correct answer: A

Rationale: Exhalation (expiration) involves active muscle contraction, specifically the diaphragm and intercostal muscles, to decrease the volume of the thoracic cavity and push air out of the lungs. In contrast, inhalation (inspiration) is a passive process where the diaphragm and external intercostal muscles contract to increase the thoracic cavity volume, allowing air to flow into the lungs. Choice B is incorrect as exhalation removes carbon dioxide-rich air and inhalation brings in oxygen-rich air. Choice C is incorrect because both exhalation and inhalation can occur through the nose or mouth. Choice D is inaccurate as inhalation humidifies and warms the air, while exhalation cools and dries it.

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