Nursing Elites

1. Balance the following redox reaction in acidic solution: I⁻ (aq) + Cr₂O₇²⁻ (aq) -> I₂ (aq) + Cr³⁺ (aq). Identify the oxidizing agent and reducing agent.

• A. I⁻ is oxidized, Crâ‚‚O₇²⁻ is reduced
• B. I⁻ is reduced, Crâ‚‚O₇²⁻ is oxidized
• C. Both I⁻ and Crâ‚‚O₇²⁻ are oxidized
• D. Both I⁻ and Crâ‚‚O₇²⁻ are reduced

Correct answer: B

Rationale: In the given redox reaction, I⁻ is gaining electrons to form I₂, which means I⁻ is being reduced (undergoing reduction). On the other hand, Cr₂O₇²⁻ is losing electrons to form Cr³⁺, indicating that Cr₂O₇²⁻ is being oxidized (undergoing oxidation). Therefore, I⁻ is the reducing agent and Cr₂O₇²⁻ is the oxidizing agent. Choice A is incorrect because I⁻ is being reduced, not oxidized. Choice C is incorrect as both species cannot be oxidized in the same reaction. Choice D is incorrect as both species cannot be reduced in the same reaction.

2. What energy conversion occurs in a solar cell?

• A. Electrical energy to light energy
• B. Chemical energy to electrical energy
• C. Solar energy to thermal energy
• D. Solar energy to electrical energy

Correct answer: D

Rationale: Solar cells, also known as photovoltaic cells, convert solar energy from sunlight directly into electrical energy through a process called the photovoltaic effect. This process involves the absorption of photons from sunlight, which then generate an electric current. Choice A is incorrect because solar cells do not convert electrical energy into light energy. Choice B is incorrect as solar cells do not involve chemical energy conversion. Choice C is incorrect because solar cells do not primarily convert solar energy into thermal energy. Therefore, the correct answer is D) Solar energy to electrical energy.

3. Which of the following cell organelles is the site of lipid synthesis?

• A. smooth endoplasmic reticulum
• B. ribosome
• C. rough endoplasmic reticulum
• D. Golgi apparatus

Correct answer: A

Rationale: The correct answer is the smooth endoplasmic reticulum. This organelle lacks ribosomes on its surface, unlike the rough endoplasmic reticulum, which is involved in protein synthesis. The enzymes present in the smooth endoplasmic reticulum are responsible for synthesizing lipids such as phospholipids and steroids. Choice B, ribosomes, are responsible for protein synthesis and not lipid synthesis. Choice C, rough endoplasmic reticulum, is involved in protein synthesis due to the presence of ribosomes. Choice D, Golgi apparatus, is responsible for modifying, sorting, and packaging proteins for secretion, not lipid synthesis.

4. What is the term for the gradual loss of topsoil due to wind or water erosion?

• A. Desertification
• B. Leaching
• C. Salinization
• D. Acidification

Correct answer: A

Rationale: A) Desertification is the correct term for the gradual loss of topsoil due to wind or water erosion. It refers to the process by which fertile land becomes desert, usually due to factors like drought, deforestation, or inappropriate agriculture practices. This process can lead to the degradation of land and contribute to the expansion of deserts. B) Leaching is the process in which minerals are washed out of the soil by water moving downwards through it. This is different from the loss of topsoil due to erosion. C) Salinization occurs when salt accumulates in the soil, typically as a result of irrigation in arid regions. While salinization affects soil quality, it is not specifically related to the gradual loss of topsoil due to erosion. D) Acidification refers to the decrease in soil pH, often caused by factors like acid rain or the use of acidic fertilizers. This process is distinct from the gradual loss of topsoil due to erosion.

5. What is the formula to calculate gravitational potential energy near the Earth's surface?

• A. Potential Energy = Mass × Acceleration
• B. Potential Energy = Force × Distance
• C. Potential Energy = Mass × Height × Gravity
• D. Potential Energy = Mass × Acceleration due to gravity × Height

Correct answer: D

Rationale: The correct formula to calculate gravitational potential energy near the Earth's surface is Potential Energy = Mass × Acceleration due to gravity × Height. This formula considers the mass of the object, the specific acceleration due to gravity near the Earth's surface (approximately 9.81 m/s^2), and the vertical distance from the reference point. Choice A is incorrect as it does not include height in the formula. Choice B is incorrect as it involves force instead of acceleration due to gravity. Choice C is incorrect as it multiplies mass, height, and gravity, missing the actual acceleration due to gravity term.

Similar Questions