Nursing Elites

1. What is the coefficient of oxygen in the balanced chemical equation for the combustion of methane (CH₄)?

• A. 1
• B. 2
• C. 3
• D. 4

Correct answer: B

Rationale: In the balanced chemical equation for the combustion of methane, CH₄ + 2O₂ → CO₂ + 2H₂O, the coefficient of oxygen (O₂) is 2. This indicates that two molecules of oxygen are required to react with one molecule of methane to produce carbon dioxide and water, ensuring the equation is balanced. Choice A is incorrect because the coefficient of oxygen is not 1 but 2. Choices C and D are incorrect as they do not represent the correct coefficient of oxygen in the balanced equation. Understanding the coefficients in a balanced chemical equation is crucial for accurately representing the stoichiometry of the reaction.

2. What type of intermolecular force is responsible for the high surface tension of water?

• A. Hydrogen bonding
• B. London dispersion forces
• C. Ionic bonding
• D. Metallic bonding

Correct answer: A

Rationale: The high surface tension of water is primarily due to the strong hydrogen bonding between water molecules. Hydrogen bonding is a specific type of intermolecular force that occurs between a hydrogen atom covalently bonded to a highly electronegative atom, like oxygen in water, and another electronegative atom nearby. This unique interaction results in a strong attraction between water molecules at the surface, leading to the cohesive forces responsible for the high surface tension of water. Choices B, C, and D are incorrect because London dispersion forces, ionic bonding, and metallic bonding do not account for the high surface tension observed in water. London dispersion forces are relatively weaker intermolecular forces, while ionic and metallic bonding are types of intramolecular forces that do not directly contribute to the surface tension of water.

3. Which of the following best describes a function carried out by the circulatory system and the integumentary system working together?

• A. Removal of excess heat from the body
• B. Hormonal regulation of blood pressure
• C. Transport of oxygen in the body
• D. Production of red blood cells in the bone marrow

Correct answer: A

Rationale: The correct answer is A: Removal of excess heat from the body. The circulatory system, which includes blood vessels and the heart, works with the integumentary system, which consists of the skin, to regulate body temperature by removing excess heat. This process involves blood vessels near the skin's surface dilating to release heat and constricting to conserve heat, a mechanism crucial for maintaining homeostasis. Option B, Hormonal regulation of blood pressure, is incorrect as it does not accurately describe the collaborative function of these systems in regulating body temperature. Option C, Transport of oxygen in the body, is incorrect as it focuses on a different function of the circulatory system. Option D, Production of red blood cells in the bone marrow, is incorrect as it pertains to the skeletal and hematopoietic systems, not the circulatory and integumentary systems working together to regulate body temperature.

4. Which part of the brainstem is responsible for controlling vital functions such as heart rate, blood pressure, and breathing?

• A. Medulla oblongata
• B. Pons
• C. Midbrain
• D. Cerebellum

Correct answer: A

Rationale: The medulla oblongata is the correct answer. It is responsible for controlling vital functions such as heart rate, blood pressure, and breathing. This part of the brainstem contains centers that regulate these essential autonomic functions to maintain homeostasis in the body. The pons and midbrain are also parts of the brainstem, but they are not primarily responsible for controlling these vital functions. The cerebellum, on the other hand, is involved in coordination and balance, not in regulating vital functions like heart rate, blood pressure, and breathing.

5. In a single displacement reaction, one element takes the place of another element in a compound. Which of the following is an example?

• A. 2H2 + O2 -> 2H2O
• B. Zn + 2HCl -> ZnCl2 + H2
• C. CaCO3 -> CaO + CO2
• D. CH4 + 2O2 -> CO2 + 2H2O

Correct answer: B

Rationale: Option B demonstrates a single displacement reaction where zinc (Zn) displaces hydrogen (H) in hydrochloric acid (HCl) to produce zinc chloride (ZnCl2) and hydrogen gas (H2). This reaction exemplifies the concept of one element (Zn) replacing another element (H) in a compound (HCl), which is characteristic of single displacement reactions. Choices A, C, and D do not involve a single element displacing another in a compound, making them incorrect. In choice A, hydrogen and oxygen combine to form water, which is not a single displacement reaction. In choice C, calcium carbonate decomposes into calcium oxide and carbon dioxide, not involving displacement of elements. In choice D, methane reacts with oxygen to form carbon dioxide and water, which is a combustion reaction, not a single displacement reaction.

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