Nursing Elites

1. Which of the following is a property of an acid?

• A. Bitter taste
• B. Slippery feel
• C. Reacts with bases
• D. Sweet taste

Correct answer: C

Rationale: The correct property of an acid is that it 'reacts with bases.' Acids are known for their ability to react with bases to form salts and water through a process called neutralization. This unique reaction distinguishes acids from other substances and is a fundamental characteristic of acids in chemistry. Choices A, B, and D are incorrect. Acids do not have a bitter taste (Choice A), a slippery feel (Choice B), or a sweet taste (Choice D). These properties are not typical of acids and may lead to confusion if associated with acids.

2. Carbon-12 and carbon-14 are isotopes. What do they have in common?

• A. Number of nuclear particles
• B. Number of protons
• C. Number of neutrons
• D. Mass number

Correct answer: C

Rationale: Isotopes are atoms of the same element with the same number of protons (which determines the element) but different numbers of neutrons. Both carbon-12 and carbon-14 have 6 protons (hence they are both carbon atoms) but different numbers of neutrons: carbon-12 has 6 neutrons, while carbon-14 has 8 neutrons. Therefore, the correct answer is the number of neutrons. Choices A, B, and D are incorrect because isotopes may have different numbers of nuclear particles (protons + neutrons), protons, and mass numbers, respectively.

3. What is 0 K equal to in °C?

• A. -300°C
• B. -273°C
• C. -250°C
• D. -200°C

Correct answer: B

Rationale: 0 Kelvin, also known as absolute zero, is equal to -273°C. This is the point at which all molecular motion stops, making it the lowest possible temperature on the Kelvin scale. Choice A (-300°C) is incorrect as it is not the correct conversion of 0 K to °C. Choice C (-250°C) and Choice D (-200°C) are also incorrect as they do not correspond to the accurate conversion of 0 K to °C.

4. Which of these represents a strong acid?

• A. CH₃COOH
• B. Hâ‚‚SOâ‚„
• C. NH₃
• D. KOH

Correct answer: B

Rationale: Among the options provided, H₂SO₄ (sulfuric acid) represents a strong acid. Strong acids completely ionize in water to produce a high concentration of H+ ions. Sulfuric acid is a strong acid known for its ability to dissociate almost completely in water, making it a strong acid. Choice A, CH₃COOH (acetic acid), is a weak acid that only partially dissociates in water. Choices C and D, NH₃ (ammonia) and KOH (potassium hydroxide), are bases and not acids.

5. 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.

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