Nursing Elites

1. Which of the following is a colligative property of a solution?

• A. Freezing point depression
• B. Viscosity
• C. Surface tension
• D. Boiling point elevation

Correct answer: A

Rationale: A colligative property is a property that depends on the number of solute particles in a solution, not on the identity of the solute particles. Freezing point depression is one such property, where adding a solute to a solvent lowers the freezing point of the solution compared to the pure solvent. This phenomenon occurs because the presence of solute particles disrupts the formation of the regular crystal lattice structure, requiring a lower temperature for solidification to occur. Choices B, C, and D are not colligative properties. Viscosity and surface tension are not dependent on the number of solute particles but on intermolecular forces and molecular interactions. Boiling point elevation is another colligative property, but in this case, the question asked for a colligative property of a solution, making freezing point depression the correct answer.

2. What is the simplest form of a substance that is represented by a letter or letters?

• A. Compound
• B. Mixture
• C. Element
• D. Molecule

Correct answer: C

Rationale: The correct answer is C, 'Element.' An element is the most basic form of a substance that cannot be broken down further by chemical reactions. Each element is represented by a unique symbol, typically consisting of one or two letters. Choice A, 'Compound,' is incorrect as compounds are formed by the combination of two or more elements. Choice B, 'Mixture,' is also incorrect as mixtures are composed of two or more substances physically combined. Choice D, 'Molecule,' refers to the smallest unit of a compound that retains the chemical properties of that compound, not the simplest form of a substance represented by a symbol.

3. You contain two odorous gases in vials with porous plugs. Gas A has twice the mass of Gas B. Which observation is most likely?

• A. You will smell Gas A before you smell Gas B.
• B. You will smell Gas B before you smell Gas A.
• C. You will smell Gas A but not Gas B.
• D. You will smell Gas B but not Gas A.

Correct answer: A

Rationale: The rate of effusion of a gas is inversely proportional to the square root of its molar mass. Since Gas A has twice the mass of Gas B, Gas A will effuse more slowly than Gas B. Therefore, you will likely smell Gas A before you smell Gas B as Gas A will escape and diffuse through the porous plug at a slower rate compared to Gas B. Choice A is correct because Gas A, with its higher molar mass, will take longer to effuse through the porous plug, causing you to smell it first. Choices B, C, and D are incorrect as they do not consider the relationship between molar mass and effusion rate.

4. How many pairs of electrons are shared between two atoms in a single bond?

• A. 1
• B. 2
• C. 3
• D. 4

Correct answer: A

Rationale: In a single bond, two atoms share one pair of electrons. This shared pair of electrons is what holds the atoms together in the bond. Therefore, the correct answer is A: 1. Choices B, C, and D are incorrect because they do not represent the number of electron pairs shared in a single bond.

5. What is the correct name of MgO?

• A. Manganese oxide
• B. Magnesium oxide
• C. Magnesium oxate
• D. Magnesium hydroxide

Correct answer: B

Rationale: The correct name of MgO is Magnesium oxide. Mg represents the chemical symbol for magnesium, and O represents the chemical symbol for oxygen. When these elements combine, they form magnesium oxide. Option A, Manganese oxide, is incorrect as it refers to a compound of manganese and oxygen, not magnesium. Option C, Magnesium oxate, is not a valid chemical compound name. Option D, Magnesium hydroxide, refers to a different compound consisting of magnesium, oxygen, and hydrogen.

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