Nursing Elites

1. What is the pH of a solution with a hydrogen ion concentration of \(1 \times 10^{-9}\) M?

• A. 5
• B. 7
• C. 9
• D. 11

Correct answer: c

Rationale: The pH is calculated as the negative logarithm (base 10) of the hydrogen ion concentration. In this case, \(-\log(1 \times 10^{-9}) = 9\).

2. Antiparticles possess properties opposite to their corresponding particles. Which of the following is the antiparticle of a neutron?

• A. Antineutrino
• B. Positron
• C. Antiproton
• D. Electron

Correct answer: A

Rationale: The correct answer is A: Antineutrino. Antiparticles possess properties that are opposite to their corresponding particles. A neutron is a neutral subatomic particle found in the nucleus of an atom. Its antiparticle, the antineutrino, has opposite properties, such as having no electric charge compared to the neutron's neutral charge. A positron (B) is the antiparticle of an electron, an antiproton (C) is the antiparticle of a proton, and an electron (D) is not an antiparticle. Therefore, the antiparticle of a neutron is the antineutrino.

3. What is the process by which muscles convert chemical energy (ATP) into mechanical energy (movement)?

• A. Photosynthesis
• B. Cellular respiration
• C. Muscle contraction
• D. The sliding filament theory

Correct answer: D

Rationale: The correct answer is D, the sliding filament theory. This theory explains how muscle contraction occurs at a molecular level. During muscle contraction, actin and myosin filaments slide past each other, causing the muscle to shorten and generate movement. This process requires the conversion of chemical energy stored in ATP into mechanical energy to power muscle contractions. Options A and B, photosynthesis and cellular respiration, involve energy production in plants and cells but are not directly related to muscle movement. Option C, muscle contraction, is a broad term that encompasses the entire process of muscle movement, while option D specifically addresses the molecular mechanism behind muscle contraction.

4. Why are isotopes of the same element chemically similar?

• A. They have the same number of protons.
• B. They have the same number of electrons.
• C. Their chemical properties are identical.
• D. They share the same electron configuration.

Correct answer: A

Rationale: They have the same number of protons. This determines the element's identity and its interactions with other elements, leading to similar chemical behavior, even if the number of neutrons differs.

5. Which vitamin plays a vital role in muscle function and helps prevent muscle weakness and fatigue?

• A. Vitamin A
• B. Vitamin B12
• C. Vitamin D
• D. Vitamin E

Correct answer: B

Rationale: The correct answer is B: Vitamin B12. Vitamin B12 plays a crucial role in muscle function by aiding in the production of red blood cells, which carry oxygen to the muscles. This vitamin also helps maintain the health of nerves that control muscle movements. Deficiency in vitamin B12 can lead to muscle weakness and fatigue due to decreased oxygen delivery and impaired nerve function in the muscles. Vitamin A is important for vision and immune function, Vitamin D is crucial for bone health, and Vitamin E is an antioxidant that protects cells from damage, but they do not have the same direct impact on muscle function as Vitamin B12.

6. Which property of a substance remains constant regardless of changes in its shape or size?

• A. Mass
• B. Weight
• C. Volume
• D. Density

Correct answer: a

Rationale: Mass is the measure of the amount of matter in an object and remains constant regardless of changes in its shape or size.

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