Nursing Elites

1. On what concept is Kelvin based?

• A. Freezing point
• B. Absolute zero
• C. Boiling point
• D. Evaporation point

Correct answer: B

Rationale: The correct answer is B: Absolute zero. Kelvin is based on the concept of absolute zero, which is the point where molecular movement ceases entirely. This temperature scale starts at absolute zero (0K), where theoretically no molecular movement occurs. Choices A, C, and D are incorrect because Kelvin is not based on the freezing point, boiling point, or evaporation point, but rather on the absolute absence of molecular motion.

2. What is the correct formula for silver hydroxide?

• A. AgO
• B. AgOH
• C. AgH
• D. AgH₂O

Correct answer: B

Rationale: The correct formula for silver hydroxide is AgOH. Silver hydroxide is formed by the combination of the silver ion (Ag⁺) with the hydroxide ion (OH⁻) to create AgOH. It is essential to note that the hydroxide ion consists of one oxygen and one hydrogen atom, thus the formula AgOH. Choices A, C, and D are incorrect as they do not accurately represent the composition of silver hydroxide.

3. Which intermolecular force is the strongest?

• A. Dipole interactions
• B. Dispersion forces
• C. Hydrogen bonding
• D. Van der Waals forces

Correct answer: C

Rationale: Hydrogen bonding is the strongest intermolecular force due to its specific interaction between a hydrogen atom and a highly electronegative atom like nitrogen, oxygen, or fluorine. This type of bonding results in a very strong attraction between molecules, making it the strongest intermolecular force among the options provided. Dipole interactions (choice A) are weaker than hydrogen bonding as they occur between polar molecules. Dispersion forces (choice B) are the weakest intermolecular forces and are caused by temporary fluctuations in electron distribution. Van der Waals forces (choice D) are a broader term that encompasses dipole interactions and dispersion forces, making them weaker than hydrogen bonding.

4. What is the oxidation state of the oxygen atom in the compound NaOH?

• A. -2
• B. -1
• C. 0
• D. +2

Correct answer: B

Rationale: In the compound NaOH (sodium hydroxide), the oxidation state of the sodium ion (Na) is +1 as it commonly has a +1 charge in ionic compounds. Oxygen (O) typically has an oxidation state of -2 in most compounds. Since the compound is electrically neutral and the overall charge is zero, the sum of the oxidation states of all atoms in the compound must be zero. Therefore, considering that sodium has an oxidation state of +1, the oxygen atom in NaOH must have an oxidation state of -1 to balance the charges and overall neutrality of the compound. Choice A (-2) is incorrect as this is not the oxidation state of oxygen in this compound. Choice C (0) is incorrect as oxygen in NaOH does not have an oxidation state of 0. Choice D (+2) is incorrect as oxygen typically has a negative oxidation state in compounds, not a positive one.

5. What type of reaction involves atoms attempting to achieve stable electron configurations?

• A. Chemical
• B. Nuclear
• C. Physical
• D. Mechanical

Correct answer: A

Rationale: In a chemical reaction, atoms interact to achieve stable electron configurations through the formation of new chemical bonds or the breaking of existing ones. This process aims to reach a more stable state by filling or emptying electron orbitals, leading to the formation of new substances with more stable configurations. Choice B, nuclear reactions, involve changes in the atomic nucleus rather than electron configurations. Choice C, physical reactions, involve changes in physical state or appearance without changing the chemical makeup. Choice D, mechanical reactions, do not involve the rearrangement of electrons to achieve stable configurations.

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