Nursing Elites

1. What is the primary factor that determines whether a solute will dissolve in a solvent?

• A. Temperature
• B. Pressure
• C. Molecular structure
• D. Particle size

Correct answer: C

Rationale: The primary factor that determines whether a solute will dissolve in a solvent is the molecular structure. The compatibility of the solute's molecules with the solvent's molecules is crucial for dissolution to occur. While temperature, pressure, and particle size can influence the rate of dissolution, they are not the primary factors determining solubility. Molecular structure plays a key role in determining if a solute will form favorable interactions with the solvent, which is essential for dissolution to take place effectively. Temperature can affect solubility by changing the kinetic energy of molecules, pressure typically has a minor effect on solubility except for gases, and particle size influences the rate of dissolution by increasing surface area, but none of these factors are as fundamentally important as molecular structure in determining solubility.

2. Which of the following cations is found at the center of a heme?

• A. Cr (III)
• B. Cu (II)
• C. Iron (II)
• D. Iron (III)

Correct answer: C

Rationale: The correct answer is Iron (II) (Fe2+), which is the cation found at the center of a heme group. Heme contains an iron (II) ion that is coordinated within the porphyrin ring structure. This iron ion is crucial for the function of heme in binding and transporting oxygen in hemoglobin and myoglobin. Choice A (Cr (III)) is incorrect as chromium is not typically found at the center of a heme group. Choice B (Cu (II)) is incorrect as copper is not the cation typically present in heme. Choice D (Iron (III)) is also incorrect as heme predominantly contains iron (II) at its center, not iron (III).

3. How are the frequency and wavelength of a wave related?

• A. Inversely proportional
• B. Directly proportional
• C. No relationship
• D. Dependent on the medium

Correct answer: A

Rationale: The correct answer is that the frequency and wavelength of a wave are inversely proportional. This relationship is defined by the wave equation: speed = frequency x wavelength. When the frequency of a wave increases, its wavelength decreases, and vice versa. This means that as one quantity increases, the other decreases in a consistent manner, illustrating an inverse relationship between frequency and wavelength. Choice B, 'Directly proportional,' is incorrect because an increase in frequency does not lead to an increase in wavelength; they move in opposite directions. Choice C, 'No relationship,' is incorrect as frequency and wavelength are interconnected as described above. Choice D, 'Dependent on the medium,' is incorrect because the relationship between frequency and wavelength is a fundamental property of waves and is not solely determined by the medium through which the wave propagates.

4. The Minimum Inhibitory Concentration (MIC) of an antibiotic refers to:

• A. The lowest concentration that kills bacteria
• B. The dose required for 50% bacterial inhibition
• C. The time it takes for an antibiotic to work
• D. The spectrum of bacteria the antibiotic targets

Correct answer: B

Rationale: A) The lowest concentration that kills bacteria is known as the Minimum Bactericidal Concentration (MBC), not the Minimum Inhibitory Concentration (MIC). MIC is the lowest concentration of an antibiotic that inhibits visible growth of bacteria. B) The MIC of an antibiotic is the concentration at which bacterial growth is inhibited by 50%. This concentration is used to determine the effectiveness of an antibiotic against a specific bacterium. C) The time it takes for an antibiotic to work is not described by the MIC. MIC is a measure of concentration, not time. D) The spectrum of bacteria the antibiotic targets is not defined by the MIC. The MIC value is specific to a particular antibiotic and bacterium, regardless of the spectrum of activity of the antibiotic.

5. A ball is thrown horizontally off a cliff. Which of the following forces is responsible for its downward motion?

• A. The force of throwing
• B. Normal force from the air
• C. Tension force from the string (if used)
• D. Gravitational force

Correct answer: D

Rationale: The gravitational force is responsible for the downward motion of the ball. When the ball is thrown horizontally off a cliff, the only force acting on it in the vertical direction is the force of gravity, which pulls the ball downward towards the ground. The other forces mentioned (force of throwing, normal force from the air, tension force from the string) do not contribute to the ball's downward motion in this scenario. The force of throwing initiates the horizontal motion, the normal force from the air opposes the ball's motion through air resistance, and tension force from the string would only be relevant if a string were attached to the ball. Therefore, gravitational force is the primary force responsible for the ball's downward motion in this situation.

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