Nursing Elites

1. Which element has an atomic mass greater than that of sodium?

• A. Boron
• B. Oxygen
• C. Fluorine
• D. Silicon

Correct answer: D

Rationale: Silicon has an atomic mass greater than that of sodium. The atomic mass of silicon is approximately 28.0855 u, whereas the atomic mass of sodium is approximately 22.9898 u. Therefore, silicon has a greater atomic mass compared to sodium. Boron, Oxygen, and Fluorine have atomic masses lower than sodium, making them incorrect choices in this context.

2. Which state of matter has a definite volume but takes the shape of its container?

• A. Gas
• B. Liquid
• C. Solid
• D. Plasma

Correct answer: B

Rationale: The state of matter that has a definite volume but takes the shape of its container is a 'Liquid.' Liquids have a fixed volume but can change their shape to fit the container they are in. This property distinguishes liquids from solids, which have both a definite shape and volume, and gases, which do not have a fixed volume or shape. Therefore, the correct answer is 'Liquid.' Choice A, 'Gas,' is incorrect because gases do not have a definite volume or shape. Choice C, 'Solid,' is incorrect as solids have a definite shape and volume. Choice D, 'Plasma,' is incorrect because plasma is a state of matter where atoms have been ionized and do not have a fixed volume or shape.

3. Which of the following factors would not affect rates of reaction?

• A. Temperature
• B. Surface area
• C. Pressure
• D. Time

Correct answer: D

Rationale: Time would not directly affect rates of reaction. The rate of a chemical reaction is determined by factors that affect the frequency of successful collisions between reactant molecules, leading to a reaction. Temperature, surface area, and pressure can influence reaction rates by impacting the kinetic energy of molecules, the exposed surface for collisions, and the concentration of reactants, respectively. However, time, in the context of this question, does not alter the rate of reaction but may affect the extent of the reaction or the amount of product formed over time.

4. Which element is a metalloid?

• A. Silicon
• B. Lead
• C. Helium
• D. Aluminum

Correct answer: A

Rationale: The correct answer is 'Silicon.' Silicon is a metalloid, which means it has properties of both metals and nonmetals. It is commonly used in electronic devices due to its semiconductor properties. Lead (Choice B) is a metal, Helium (Choice C) is a noble gas, and Aluminum (Choice D) is a metal.

5. What is the pH of acids?

• A. 7.5
• B. < 7
• C. > 7
• D. 7

Correct answer: B

Rationale: The correct answer is B: < 7. Acids have a pH lower than 7, indicating higher acidity. A pH below 7 signifies an acidic solution, with lower values indicating stronger acids. Choice A (7.5) is incorrect as it is greater than 7, which is alkaline. Choice C (> 7) is incorrect as values greater than 7 represent alkaline/basic solutions. Choice D (7) is incorrect because a pH of 7 is neutral, not acidic.

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