Nursing Elites

1. Which of the following is a characteristic of an exothermic reaction?

• A. It absorbs heat
• B. It releases heat
• C. It remains neutral
• D. It requires energy input

Correct answer: B

Rationale: An exothermic reaction is characterized by the release of heat. During an exothermic reaction, energy is released in the form of heat to the surroundings, resulting in a temperature increase. This distinguishes it from endothermic reactions, which absorb heat from the surroundings. Choice A is incorrect because exothermic reactions do not absorb heat; instead, they release heat. Choice C is incorrect as exothermic reactions do not remain neutral; they involve a net release of energy. Choice D is incorrect as exothermic reactions do not require energy input; instead, they release energy.

2. Which branch of chemistry deals with the quantities and numeric relationships between compounds in a chemical reaction?

• A. Stoichiometry
• B. Molecular chemistry
• C. Atomic chemistry
• D. Thermodynamics

Correct answer: A

Rationale: Stoichiometry is the branch of chemistry that deals with the quantitative relationships between reactants and products in chemical reactions. It involves the calculation of quantities of substances consumed and produced in a chemical reaction based on the balanced chemical equation. Choice B, 'Molecular chemistry,' is incorrect as it focuses on the structure, properties, and reactions of molecules. Choice C, 'Atomic chemistry,' is incorrect as it primarily deals with the study of atoms and their interactions. Choice D, 'Thermodynamics,' is incorrect as it pertains to the study of energy and heat transfer in chemical and physical processes.

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. What charge do Group IIIA elements have?

• A. +1
• B. +2
• C. +3
• D. 0

Correct answer: C

Rationale: Group IIIA elements, also known as Group 13 elements, have a common oxidation state of +3. This is because they have three valence electrons and tend to lose these electrons to achieve a stable electron configuration, resulting in a +3 charge. Choice A (+1) and Choice B (+2) are incorrect because Group IIIA elements typically lose all three valence electrons to attain a stable configuration, leading to a +3 charge. Choice D (0) is incorrect as these elements do not gain electrons but rather lose them, resulting in a positive charge.

5. What type of chemical reaction involves the combination of two elements to form a product?

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

Correct answer: C

Rationale: A synthesis reaction involves the combination of two or more substances to form a single, more complex product. In the context of chemical reactions, it specifically refers to the combination of two elements to form a compound. Therefore, the correct answer is C. Decomposition reactions involve the breakdown of a single compound into simpler substances (opposite of synthesis). Combustion reactions involve a substance reacting with oxygen to produce heat and light, not the combination of elements. Double replacement reactions involve the exchange of ions between two compounds, leading to the formation of two new compounds, not the combination of two elements.

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