Nursing Elites

1. Which element is used in fire extinguishers to smother flames by displacing oxygen?

• A. Nitrogen
• B. Carbon dioxide
• C. Helium
• D. Argon

Correct answer: B

Rationale: Carbon dioxide is the correct answer. It is used in fire extinguishers because it displaces oxygen, which is necessary for combustion. When carbon dioxide is released onto a fire, it reduces the oxygen concentration around the flames, effectively smothering the fire. This disruption of oxygen availability interrupts the chemical reaction that sustains the fire. Nitrogen (Choice A), helium (Choice C), and argon (Choice D) are not typically used in fire extinguishers for smothering flames by displacing oxygen. Nitrogen is an inert gas that can displace oxygen but is not as effective as carbon dioxide in fire suppression.

2. Which type of RNA carries the genetic code from DNA to ribosomes?

• A. Ribosomal RNA (rRNA)
• B. Transfer RNA (tRNA)
• C. Messenger RNA (mRNA)
• D. Deoxyribonucleic acid (DNA)

Correct answer: C

Rationale: - Messenger RNA (mRNA) carries the genetic information from DNA in the cell's nucleus to the ribosomes in the cytoplasm, where protein synthesis occurs. - Ribosomal RNA (rRNA) is a component of the ribosomes where protein synthesis takes place. - Transfer RNA (tRNA) is responsible for bringing amino acids to the ribosomes during protein synthesis. - Deoxyribonucleic acid (DNA) is the genetic material that contains the instructions for building and maintaining an organism. DNA is transcribed into mRNA before being translated into proteins.

3. Which of the following correctly describes a strong acid?

• A. A strong acid completely ionizes in water.
• B. A strong acid donates more than one proton.
• C. A strong acid contains at least one metal atom.
• D. A strong acid will not decompose.

Correct answer: A

Rationale: The correct answer is A. A strong acid is defined as an acid that completely ionizes in water, meaning it dissociates fully into its constituent ions in solution. This characteristic differentiates strong acids from weak acids, which do not fully dissociate in water. Choice B is incorrect because the number of protons donated does not solely define the strength of an acid. Choice C is incorrect as strong acids are not defined by the presence of metal atoms, and Choice D is incorrect because all acids can decompose, but the strength of the acid is based on its ability to ionize in water.

4. What is the relationship between force and acceleration according to Newton's second law?

• A. Force is directly proportional to acceleration
• B. Force is inversely proportional to acceleration
• C. Force has no relation to acceleration
• D. Force causes deceleration, not acceleration

Correct answer: A

Rationale: According to Newton's second law of motion, the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. This relationship is mathematically expressed as F = ma, where F represents force, m represents mass, and a represents acceleration. Therefore, an increase in force will result in a proportional increase in acceleration, supporting the statement that force is directly proportional to acceleration. Choice B is incorrect as it suggests an inverse relationship, which is not consistent with Newton's second law. Choice C is incorrect because force and acceleration are indeed related as per Newton's second law. Choice D is incorrect as force can cause acceleration or deceleration depending on the direction of the force relative to the motion of the object, but it does not exclusively cause deceleration.

5. Which of the following is a common property of both acids and bases?

• A. React with metals to produce hydrogen gas
• B. Taste sour
• C. Turn blue litmus paper red
• D. Conduct electricity when dissolved in water

Correct answer: D

Rationale: The correct answer is D. Both acids and bases can conduct electricity when dissolved in water. Acids ionize in water to produce H+ ions, which can carry an electric current, while bases ionize to produce OH- ions, which also conduct electricity. The other options are not common properties of both acids and bases. Reacting with metals to produce hydrogen gas is characteristic of acids, tasting sour is a property of acids, and turning blue litmus paper red is a property of bases, not a common property shared by both.

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