Nursing Elites

1. Which of the following statements describes a chemical property of water?

• A. Water has a pH of 1.
• B. A water molecule contains 2 hydrogen atoms and 1 oxygen atom.
• C. A water molecule contains 2 oxygen atoms and 1 hydrogen atom.
• D. The chemical formula for water is HO.

Correct answer: B

Rationale: The correct answer is B because a water molecule consists of two hydrogen atoms and one oxygen atom, which is a fundamental chemical property of water. The pH of water is not a property of the water molecule itself but rather a measure of its acidity or alkalinity. Choice C is incorrect as it describes a different molecule, not water. Choice D provides an incorrect chemical formula for water, which is H2O.

2. Which of the following infectious diseases can be caused by a protozoan parasite?

• A. Measles
• B. Malaria
• C. Mumps
• D. Mononucleosis

Correct answer: B

Rationale: The correct answer is B: Malaria. Malaria is caused by Plasmodium, a protozoan parasite transmitted through the bite of infected mosquitoes. Measles and mumps are viral diseases caused by separate viruses. Mononucleosis, on the other hand, is caused by the Epstein-Barr virus, which is also a viral infection. Therefore, choices A, C, and D are incorrect as they are caused by viruses, not protozoa.

3. What is the structure that attaches to each chromosome during mitosis?

• A. Centromere
• B. Telomere
• C. Spindle apparatus
• D. Nucleolus

Correct answer: A

Rationale: The correct answer is the centromere. It is the structure that attaches to each chromosome during mitosis. The centromere serves as the attachment point for spindle fibers during cell division, ensuring proper distribution of chromosomes to daughter cells. Telomeres are found at the ends of chromosomes, providing protection and stability. The spindle apparatus is responsible for separating chromosomes during cell division. The nucleolus, located within the nucleus, is involved in ribosomal RNA synthesis and not in chromosome attachment during mitosis.

4. What is the difference between a real image and a virtual image formed by a lens?

• A. Real images can be projected onto a screen, while virtual images cannot.
• B. Real images are always upright, while virtual images can be inverted.
• C. Real images are formed by converging lenses, while virtual images are formed by diverging lenses.
• D. All of the above are true.

Correct answer: A

Rationale: The correct answer is A. Real images can be projected onto a screen because they are formed by the actual convergence of light rays, while virtual images cannot be projected onto a screen as they appear to diverge from a point behind the lens. Real and virtual images do not have a consistent orientation (upright or inverted), so option B is incorrect. Real images are formed by both converging and diverging lenses depending on the specific scenario, so option C is not a definitive distinction. Option D is incorrect as not all the statements are true. Therefore, the only accurate general distinction between real and virtual images is that real images can be projected onto a screen, while virtual images cannot.

5. When magnesium metal reacts with hydrochloric acid, hydrogen gas is produced. What evidence suggests a chemical reaction is occurring?

• A. A change in color
• B. The formation of a gas
• C. Dissolving in a liquid
• D. No change in temperature

Correct answer: B

Rationale: The formation of a gas is evidence of a chemical reaction occurring. In this case, when magnesium metal reacts with hydrochloric acid, hydrogen gas is produced, indicating a chemical change is taking place. The production of gas is a clear indication of a chemical reaction, as new substances are being formed. A change in color might suggest a physical change, dissolving in a liquid could be a physical or chemical change depending on the context, and no change in temperature does not necessarily indicate a chemical reaction, as some reactions are endothermic or release small amounts of heat that may not be easily noticeable.

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