Nursing Elites

1. What is the primary function of enzymes?

• A. To provide energy for reactions
• B. To speed up reactions
• C. To decrease activation energy
• D. To act as a catalyst

Correct answer: B

Rationale: Enzymes function to speed up reactions by lowering the activation energy required for the reaction to occur. They act as biological catalysts, providing an alternative pathway for the reaction to proceed more rapidly without being consumed in the process. Choices A, C, and D are incorrect because enzymes do not provide energy for reactions (they do not generate energy), their primary function is not to decrease activation energy (though they do lower it), and while they act as catalysts, the primary function is to speed up reactions by lowering activation energy.

2. What can stop the penetration of alpha particles?

• A. Aluminum foil
• B. Glass
• C. Piece of paper
• D. Plastic

Correct answer: C

Rationale: Alpha particles can be stopped by a piece of paper due to their low penetration power. The paper acts as a shield, effectively blocking the alpha particles from passing through. In contrast, materials like aluminum foil, glass, and plastic are not as effective as a simple piece of paper in stopping alpha particles. Aluminum foil is more effective against beta particles, gamma rays, and x-rays due to its higher density. Glass and plastic also provide some protection against beta particles and gamma rays, but they are less effective than a piece of paper against alpha particles.

3. Which of the following substances is a base?

• A. Water
• B. Sodium chloride
• C. Ammonia
• D. Salt

Correct answer: C

Rationale: The correct answer is 'Ammonia' (Choice C) as it is a common example of a base. Bases are substances that release hydroxide ions (OH-) in aqueous solutions, helping to increase the pH level. Ammonia is a weak base that can accept a proton (H+) to form ammonium hydroxide. In contrast, water (Choice A), sodium chloride (Choice B), and salt (Choice D) are not bases; water is neutral, while sodium chloride and salt are neutral compounds composed of a cation and an anion.

4. What is the name of the group of elements that contains chlorine, fluorine, and iodine?

• A. Alkali metals
• B. Halogens
• C. Transition metals
• D. Noble gases

Correct answer: B

Rationale: The correct answer is 'Halogens.' Halogens are a group of elements that include chlorine, fluorine, and iodine. These elements are part of Group 17 in the periodic table. They share similar properties such as high reactivity and the ability to readily form compounds. Choice A, 'Alkali metals,' is incorrect as alkali metals are found in Group 1 of the periodic table, which includes elements like lithium and sodium. Choice C, 'Transition metals,' is incorrect as transition metals are located in the middle section of the periodic table, not in Group 17. Choice D, 'Noble gases,' is incorrect as noble gases are in Group 18 and include elements like helium and neon, which are chemically inert.

5. What charge do Group IIIA elements have?

• A. +1
• B. +2
• C. +3
• D. 0

Correct answer: C

Rationale: Group IIIA elements, also known as Group 13 elements, have a common oxidation state of +3. This is because they have three valence electrons and tend to lose these electrons to achieve a stable electron configuration, resulting in a +3 charge. Choice A (+1) and Choice B (+2) are incorrect because Group IIIA elements typically lose all three valence electrons to attain a stable configuration, leading to a +3 charge. Choice D (0) is incorrect as these elements do not gain electrons but rather lose them, resulting in a positive charge.

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