Nursing Elites

1. An atom has 17 protons, 20 neutrons, and 17 electrons. What is its mass, in amu?

• A. 17
• B. 20
• C. 37
• D. 54

Correct answer: C

Rationale: The atomic mass of an atom is the sum of the protons and neutrons in its nucleus. In this case, the atom has 17 protons and 20 neutrons, totaling 37 particles in the nucleus. Electrons are not considered in the atomic mass calculation as their mass is negligible compared to protons and neutrons. Therefore, the mass of the atom in atomic mass units (amu) is 37.

2. Salts are formed by the reaction between:

• A. Two acids
• B. An acid and a base
• C. Two bases
• D. A metal and a nonmetal only

Correct answer: B

Rationale: Salts are formed by the reaction between an acid and a base. This reaction is known as a neutralization reaction. In this reaction, the acid donates a proton (H+) to the base, resulting in the formation of water and a salt as the products. Choice A is incorrect because salts are not formed by the reaction of two acids. Choice C is incorrect as salts are not produced by the reaction of two bases. Choice D is incorrect because while salts can be formed from the reaction between a metal and a nonmetal, it is not the only way salts are produced.

3. What is the term for a solution that has a higher concentration of solute compared to another solution?

• A. Saturated solution
• B. Unsaturated solution
• C. Dilute solution
• D. Concentrated solution

Correct answer: D

Rationale: The correct answer is D, a concentrated solution. A concentrated solution contains a higher concentration of solute compared to another solution. This means there is a large amount of solute dissolved in the solvent, making it more concentrated than other solutions. Choices A, B, and C are incorrect. A saturated solution is one in which no more solute can be dissolved at a given temperature, an unsaturated solution can dissolve more solute at the given conditions, and a dilute solution has a low concentration of solute relative to the solvent.

4. In the reaction 4Al + 3O2 → 2Al2O3, what is the mole ratio of aluminum to oxygen?

• A. 4:3
• B. 2:3
• C. 3:2
• D. 3:4

Correct answer: A

Rationale: The balanced chemical equation shows that 4 moles of aluminum react with 3 moles of oxygen to produce 2 moles of aluminum oxide. Therefore, the mole ratio of aluminum to oxygen is 4:3. Choice B (2:3) is incorrect because it does not reflect the correct ratio based on the balanced equation. Choice C (3:2) and Choice D (3:4) are also incorrect as they do not represent the correct mole ratio of aluminum to oxygen according to the balanced chemical equation.

5. What is the significance of studying pedigrees in human genetics?

• A. Predicting the exact outcome of genetic crosses in humans.
• B. Tracing the inheritance of complex traits with multiple contributing genes.
• C. Identifying carriers of dominant genetic disorders.
• D. Determining the risk of acquiring a specific mutation de novo.

Correct answer: B

Rationale: Pedigrees are diagrams that show the relationships within a family and can be used to track the inheritance patterns of specific traits or diseases. While pedigrees can provide information on the inheritance of single gene disorders (such as identifying carriers of dominant genetic disorders, as mentioned in option C), their primary significance lies in studying complex traits with multiple contributing genes. These traits do not follow simple Mendelian inheritance patterns and are influenced by both genetic and environmental factors. By analyzing pedigrees, researchers can identify patterns of inheritance for complex traits, such as polygenic diseases or traits influenced by gene-environment interactions. Therefore, option B is the most appropriate choice as it captures the main significance of studying pedigrees in human genetics.

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