Nursing Elites

1. What does half-life refer to?

• A. Radioactive intensity to completely disappear
• B. The number of neutrons in a nucleus to double
• C. The number of protons in a nucleus to change
• D. An isotope to decay by half of its initial quantity

Correct answer: D

Rationale: Half-life refers to the time it takes for half of the radioactive atoms in a sample to decay. This means that after one half-life, half of the initial quantity of the radioactive substance will have decayed. Choice A is incorrect because radioactive intensity doesn't completely disappear during half-life. Choice B is incorrect as half-life doesn't refer to the number of neutrons doubling. Choice C is incorrect as half-life doesn't relate to the number of protons changing.

2. Imagine you have an element with atomic number 20 and mass number 40. How many neutrons does it have?

• A. 20
• B. 40
• C. 10
• D. 20

Correct answer: C

Rationale: - The atomic number (Z) represents the number of protons in an atom. In this case, the atomic number is 20. - The mass number (A) represents the total number of protons and neutrons in an atom. In this case, the mass number is 40. - To find the number of neutrons, you subtract the atomic number from the mass number: Neutrons = Mass number - Atomic number. - Neutrons = 40 - 20 = 20. - Therefore, the element with atomic number 20 and mass number 40 has 20 neutrons.

3. Which factor do colligative properties of solutions depend on?

• A. Concentration of the solvent
• B. All of the above
• C. Chemical identity of the solute
• D. Number of solute particles in solution

Correct answer: D

Rationale: Colligative properties of solutions depend on the number of solute particles in solution. These properties, such as boiling point elevation, freezing point depression, vapor pressure lowering, and osmotic pressure, are proportional to the number of solute particles present in the solution. The chemical identity of the solute or the concentration of the solvent does not influence colligative properties, making choices A and C incorrect. Therefore, the correct answer is D, the number of solute particles in solution.

4. What is the main component of stomach acid?

• A. Hydrochloric acid
• B. Bicarbonate
• C. Bile salts
• D. Enzymes

Correct answer: A

Rationale: Stomach acid, also known as gastric acid, is primarily composed of hydrochloric acid. Hydrochloric acid plays a crucial role in the digestive process by helping to break down food and kill bacteria in the stomach. Bicarbonate is a base that helps neutralize stomach acid in the small intestine, but it is not the main component of stomach acid. Bile salts are produced by the liver and stored in the gallbladder, aiding in the digestion and absorption of fats, but they are not the main component of stomach acid. Enzymes are proteins that help catalyze chemical reactions in the body, including the breakdown of food molecules during digestion, but they are not the main component of stomach acid.

5. Which of the following correctly orders the layers of the epidermis from most superficial to deepest?

• A. S. spinosum, S. basale, S. corneum, S. granulosum, S. lucidum
• B. S. corneum, S. lucidum, S. granulosum, S. spinosum, S. basale
• C. S. corneum, S. spinosum, S. basale, S. granulosum, S. lucidum
• D. S. basale, S. spinosum, S. granulosum, S. lucidum, S. corneum

Correct answer: B

Rationale: The correct order of the layers of the epidermis from most superficial to deepest is: Stratum corneum, Stratum lucidum, Stratum granulosum, Stratum spinosum, Stratum basale. Choice B, 'S. corneum, S. lucidum, S. granulosum, S. spinosum, S. basale,' provides the accurate layering from the outermost to the innermost layer of the epidermis. Choice A is incorrect as it starts with Stratum spinosum, which is not the most superficial layer. Choice C is incorrect as it places Stratum spinosum before Stratum basale. Choice D is incorrect as it starts with Stratum basale, which is the deepest layer of the epidermis.

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