Nursing Elites

1. What happens to the density of a gas when its temperature increases at constant pressure?

• A. It increases.
• B. It decreases.
• C. It remains the same.
• D. Information is insufficient.

Correct answer: B

Rationale: When the temperature of a gas increases at constant pressure, the average kinetic energy of the gas molecules increases. This leads to the gas molecules moving faster and spreading out more, which causes them to occupy a larger volume. As a result, the density of the gas decreases because the same number of gas molecules are now distributed over a larger space. Choice A is incorrect because as the gas molecules spread out, the density decreases. Choice C is incorrect because the increase in temperature leads to a decrease in density due to the increased volume occupied by the gas molecules. Choice D is incorrect because with the provided scenario of temperature increase at constant pressure, the effect on density can be determined.

2. 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.

3. Which part of the digestive system is primarily responsible for absorbing nutrients?

• A. Stomach
• B. Small intestine
• C. Esophagus
• D. Large intestine

Correct answer: B

Rationale: The small intestine is the primary site for nutrient absorption in the digestive system. It is lined with specialized cells that facilitate the absorption of nutrients such as carbohydrates, proteins, fats, vitamins, and minerals into the bloodstream for distribution throughout the body. While the stomach plays a role in digestion by breaking down food with acid and enzymes, the actual absorption of nutrients occurs mainly in the small intestine. The esophagus is responsible for transporting food from the mouth to the stomach, but it does not absorb nutrients. The large intestine primarily absorbs water and electrolytes, not nutrients.

4. Lymph nodes, found along lymphatic vessels, are important for:

• A. Storing blood
• B. Producing antibodies
• C. Filtering lymph and trapping harmful substances
• D. All of the above

Correct answer: C

Rationale: Lymph nodes are essential for filtering lymph and trapping harmful substances. They are a vital part of the immune system as they remove pathogens and harmful substances from the lymph before it returns to the bloodstream. Lymph nodes do not store blood or produce antibodies, making choice C the correct answer. Choice A is incorrect because lymph nodes do not store blood; they primarily filter lymph. Choice B is incorrect as lymph nodes do not produce antibodies; that function is mainly carried out by specialized cells within the immune system. Choice D is incorrect as lymph nodes do not perform all the functions listed, making it an incorrect answer.

5. If Silicon (Si) has an atomic mass of 28.1 AMU (atomic mass units), which of the following is the most likely number of neutrons an atom of Silicon would have?

• A. 28.1
• B. 14
• C. 28
• D. 14.2

Correct answer: B

Rationale: Silicon has an atomic number of 14, indicating it has 14 protons. The atomic mass of 28.1 AMU accounts for both protons and neutrons in the nucleus. By subtracting the atomic number from the atomic mass, we can estimate the number of neutrons in the atom. Thus, 28.1 - 14 = 14 neutrons. Choice A is incorrect as it represents the total atomic mass, not the number of neutrons. Choice C is incorrect; it is the atomic number (protons) rather than the number of neutrons. Choice D is incorrect as it is a value that does not reflect the number of neutrons in the silicon atom.

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