Nursing Elites

1. What is the process by which decomposers break down organic matter?

• A. Photosynthesis
• B. Bioremediation
• C. Decomposition
• D. Nitrification

Correct answer: C

Rationale: A) Photosynthesis is the process by which plants, algae, and some bacteria convert light energy into chemical energy to produce glucose from carbon dioxide and water. This process is not related to the breakdown of organic matter by decomposers. B) Bioremediation is the use of living organisms to clean up contaminated environments. While it involves the use of microorganisms to break down pollutants, it is not specifically focused on breaking down organic matter. C) Decomposition is the process by which decomposers such as bacteria, fungi, and other organisms break down organic matter into simpler substances. This process is essential for nutrient recycling in ecosystems. D) Nitrification is the biological oxidation of ammonia or ammonium to nitrite followed by the oxidation of nitrite to nitrate by nitrifying bacteria. This process is part of the nitrogen cycle and is not directly related to the breakdown of organic matter.

2. What is the name for the change in enthalpy (heat) associated with a chemical reaction at constant pressure?

• A. Entropy
• B. Enthalpy
• C. Gibbs free energy
• D. Heat of reaction

Correct answer: D

Rationale: The correct answer is D, Heat of reaction. The heat of reaction, also known as the enthalpy change, is the amount of heat absorbed or released during a chemical reaction at constant pressure. Entropy (A) is a measure of the disorder or randomness of a system and is not specifically related to heat changes in a chemical reaction. Enthalpy (B) is the total heat content of a system and not just the change associated with a reaction. Gibbs free energy (C) is a measure of the energy available to do work in a system at constant temperature and pressure, but it is not the specific term for the heat change in a chemical reaction.

3. Nuclear fusion powers the sun and other stars. What is the main obstacle to achieving controlled nuclear fusion on Earth for energy production?

• A. Lack of suitable materials to handle high temperatures and pressures.
• B. Limited availability of fusion fuels like deuterium and tritium.
• C. Difficulty in containing the plasma where fusion occurs.
• D. All of the above

Correct answer: D

Rationale: The main obstacle to achieving controlled nuclear fusion on Earth for energy production involves a combination of factors. A) Lack of suitable materials to handle high temperatures and pressures is a significant challenge due to the extreme conditions required for fusion reactions. B) Limited availability of fusion fuels like deuterium and tritium can pose a constraint on the scalability and sustainability of fusion energy. C) Difficulty in containing the plasma where fusion occurs is another critical issue as plasma instabilities and heat losses can hinder the efficiency of fusion reactions. Therefore, all of the options (A, B, and C) contribute to the challenges in achieving controlled nuclear fusion for energy production on Earth.

4. In a closed system with a gas at constant volume, what will happen to the temperature if the pressure is increased?

• A. The temperature will stay the same
• B. The temperature will decrease
• C. The temperature will increase
• D. It cannot be determined with the information given

Correct answer: C

Rationale: In a closed system with a gas at constant volume, according to Gay-Lussac's law, the temperature of a gas is directly proportional to its pressure. When the pressure is increased, the temperature of the gas will also increase. This relationship is a direct consequence of the ideal gas law, where pressure and temperature are directly proportional when volume is held constant. Therefore, as pressure increases in a closed system with constant volume, the temperature of the gas will increase. Choices A, B, and D are incorrect. The temperature will not stay the same (Choice A) or decrease (Choice B) when the pressure is increased in this scenario. The relationship between pressure and temperature in a closed system with constant volume allows for a definitive conclusion about the increase in temperature when pressure is increased, making Choice D, which suggests inability to determine, incorrect.

5. Iron is a transition metal, which means it often forms a cation with a charge of what?

• A. 2- or 3-
• B. 1-
• C. 2+ or 3+
• D. 1+

Correct answer: C

Rationale: The correct answer is C: 2+ or 3+. Transition metals, like iron, are known for their ability to exhibit variable oxidation states. This characteristic allows them to form cations with charges such as 2+ or 3+. Specifically, iron can form cations with these charges due to the varying electron configurations in its d-orbitals. The other choices are incorrect because transition metals typically form positively charged cations, not negatively charged ones. Additionally, while iron can form cations with charges of 2+ or 3+, it does not commonly form cations with charges of 1- or 1+. Transition metal cations play a crucial role in forming coordination complexes with ligands, highlighting their importance in various chemical reactions.

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