Nursing Elites

1. What is the name of the process by which a gas turns into a liquid?

• A. Sublimation
• B. Condensation
• C. Evaporation
• D. Deposition

Correct answer: B

Rationale: The correct answer is B: Condensation. Condensation is the process where gas transforms into a liquid. When gas cools down, it loses energy and its particles come closer, leading to the formation of liquid droplets. Sublimation is the direct transition from solid to gas without passing through the liquid state. Evaporation is the process of liquid turning into a gas, and deposition is the transition of gas directly into a solid. Therefore, choices A, C, and D are incorrect as they describe different phase transitions.

2. What type of chemical reaction is represented by AB → A + B?

• A. Synthesis
• B. Decomposition
• C. Single replacement
• D. Double replacement

Correct answer: B

Rationale: The chemical equation AB → A + B represents a decomposition reaction. In a decomposition reaction, a single compound breaks down into two or more simpler substances. In this specific reaction, compound AB is decomposed into its elements, A and B, making it a decomposition reaction. Choice A, Synthesis, involves the combination of two or more substances to form a more complex product, which is not the case here. Choices C and D, Single replacement and Double replacement, involve the exchange of ions between compounds or elements, which is not happening in the given reaction.

3. How many electrons are shared in a single covalent bond?

• A. 1
• B. 2
• C. 3
• D. 4

Correct answer: B

Rationale: The correct answer is B: '2'. In a single covalent bond, two electrons are shared between two atoms. Each atom contributes one electron to form the bond, resulting in the sharing of a total of two electrons. Choice A is incorrect because a single covalent bond involves the sharing of two electrons, not one. Choices C and D are incorrect as they do not represent the correct number of electrons shared in a single covalent bond.

4. Which of the following best describes an endothermic reaction?

• A. A reaction that absorbs heat
• B. A reaction that releases heat
• C. A reaction that does not involve heat
• D. A reaction that remains at a constant temperature

Correct answer: A

Rationale: An endothermic reaction is a process that absorbs heat from its surroundings. When a reaction absorbs heat, it leads to a decrease in the temperature of the surroundings, making choice A the correct description. In an endothermic reaction, energy is taken in from the surroundings, resulting in a decrease in temperature around the reaction site. Choice B is incorrect because a reaction that releases heat is known as an exothermic reaction. Choice C is incorrect as all reactions involve heat to some extent. Choice D is incorrect as an endothermic reaction does not remain at a constant temperature but rather absorbs heat, leading to a temperature decrease in the surroundings.

5. Which of the following types of matter changes in volume with changes in temperature and pressure?

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

Correct answer: B

Rationale: A gas changes its volume with changes in temperature and pressure due to the particles moving more rapidly at higher temperatures, and pressure affects the space between particles. Liquids have a relatively fixed volume but take the shape of their container. Solids have a definite shape and volume, so they do not change volume with changes in temperature and pressure. Plasma is a state of matter where particles are highly energized and do not have a fixed volume, but it does not exhibit volume changes with temperature and pressure variations.

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