Nursing Elites

1. Which of the following best describes a chemical change?

• A. Melting ice to form water
• B. Dissolving sugar in water
• C. Burning wood to produce ash
• D. Crushing a can to reduce its size

Correct answer: C

Rationale: A chemical change involves a chemical reaction where new substances are formed. Burning wood to produce ash is an example of a chemical change because the wood undergoes a chemical reaction to form a new substance (ash). In this process, the chemical composition of wood changes to produce ash, which is a new substance. On the other hand, melting ice to form water, dissolving sugar in water, and crushing a can to reduce its size are examples of physical changes. In these instances, the substances may change their physical state or appearance but do not undergo a chemical reaction to form new substances. Therefore, choice C is the correct answer as it represents a chemical change, while choices A, B, and D represent physical changes.

2. Enzymes are ________ molecules that serve as _______ for certain biological reactions.

• A. Enzymes are irrelevant molecules that serve as suppressors for certain biological reactions.
• B. Enzymes are acidic molecules that serve as catalysts for certain biological reactions.
• C. Enzymes are lipid molecules that serve as catalysts for certain biological reactions.
• D. Enzymes are protein molecules that serve as catalysts for certain biological reactions.

Correct answer: D

Rationale: Enzymes are protein molecules that serve as catalysts for certain biological reactions. Enzymes are biological molecules that speed up chemical reactions in living organisms by lowering the activation energy required for the reactions to occur. They are typically proteins that have specific shapes and active sites that allow them to interact with specific substrates and facilitate reactions without being consumed themselves. The other choices are incorrect because enzymes are not irrelevant, acidic, or lipid molecules; they are primarily proteins known for their catalytic properties.

3. Which of the following is the space between the lungs?

• A. Mediastinum
• B. Pericardial cavity
• C. Pleural cavity
• D. Thoracic space

Correct answer: A

Rationale: The correct answer is A, mediastinum. The mediastinum is the space between the lungs in the chest that contains the heart, major blood vessels, esophagus, trachea, and other structures. This area separates the lungs into right and left cavities. Choice B, pericardial cavity, is incorrect as it refers to the space that surrounds the heart. Choice C, pleural cavity, is not the correct answer as it is the space between the layers of the pleura surrounding each lung. Choice D, thoracic space, is a vague term and not specific to the space between the lungs.

4. Which of the following correctly describes a strong acid?

• A. A strong acid completely ionizes in water.
• B. A strong acid donates more than one proton.
• C. A strong acid contains at least one metal atom.
• D. A strong acid will not decompose.

Correct answer: A

Rationale: The correct answer is A. A strong acid is defined as an acid that completely ionizes in water, meaning it dissociates fully into its constituent ions in solution. This characteristic differentiates strong acids from weak acids, which do not fully dissociate in water. Choice B is incorrect because the number of protons donated does not solely define the strength of an acid. Choice C is incorrect as strong acids are not defined by the presence of metal atoms, and Choice D is incorrect because all acids can decompose, but the strength of the acid is based on its ability to ionize in water.

5. Based on the following evidence, what is the most likely reason that spoiled food left out in the open often contains fly larvae?

• A. The spoiled food evolves into fly larvae.
• B. Since the food is left out in the open, flies lay eggs in the food.
• C. Fly larvae are spontaneously generated by the spoiled food.
• D. People only imagine they see fly larvae in the spoiled food.

Correct answer: B

Rationale: The correct answer is B. Flies laying eggs in the food when it is left exposed to the air is a common occurrence and a logical explanation for the presence of fly larvae in spoiled food. Choice A is incorrect as food cannot evolve into fly larvae; fly larvae come from eggs laid by flies. Choice C is incorrect as fly larvae do not spontaneously generate from spoiled food but rather develop from eggs laid by flies. Choice D is incorrect as the presence of fly larvae in spoiled food is a real phenomenon, not merely imagined by people.

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