Nursing Elites

1. What does the mass number minus the atomic number equal?

• A. Number of electrons
• B. Number of neutrons
• C. Number of protons
• D. Number of isotopes

Correct answer: B

Rationale: The mass number of an atom represents the total number of protons and neutrons in its nucleus. The atomic number indicates the number of protons in the nucleus. The difference between the mass number and the atomic number provides the number of neutrons present in the nucleus of an atom. Therefore, mass number minus atomic number equals the number of neutrons. Choice A is incorrect because the number of electrons is not determined by the mass number and atomic number. Choice C is incorrect as it represents the number of protons, not the difference between the mass number and atomic number. Choice D is incorrect as isotopes refer to atoms of the same element with different numbers of neutrons, not the difference between mass number and atomic number.

2. What type of reaction occurs when an acid and a base react to form water and salt?

• A. Neutralization reaction
• B. Decomposition reaction
• C. Combustion reaction
• D. Redox reaction

Correct answer: A

Rationale: A neutralization reaction is the correct answer. In this type of reaction, an acid and a base combine to form water and salt. The acid donates a proton (H+) to the base, forming water, while the remaining ions combine to form a salt. This reaction results in the neutralization of both the acid and the base, hence the name 'neutralization reaction.' Choice B, decomposition reaction, is incorrect because it refers to a reaction where a compound breaks down into simpler substances. Choice C, combustion reaction, is incorrect as it involves a substance reacting with oxygen to produce heat and light. Choice D, redox reaction, is incorrect because it involves the transfer of electrons between reactants.

3. What type of intermolecular force is a dipole attraction?

• A. Strong
• B. Weak
• C. Medium
• D. Very strong

Correct answer: B

Rationale: A dipole attraction is considered a weak intermolecular force. It occurs between molecules with permanent dipoles, where the positive end of one molecule is attracted to the negative end of another molecule. While dipole-dipole interactions are stronger than dispersion forces, they are weaker than hydrogen bonding or ion-dipole interactions. Therefore, the correct answer is 'Weak.' Choices A, C, and D are incorrect because dipole attractions are not classified as strong, medium, or very strong intermolecular forces, but rather fall into the category of weak intermolecular forces.

4. What term refers to the average of the masses of each of its isotopes as they occur in nature?

• A. Atomic number
• B. Mass number
• C. Atomic mass
• D. Neutron number

Correct answer: C

Rationale: The correct answer is atomic mass. Atomic mass is the weighted average of the masses of an element's isotopes. It takes into account the abundance of each isotope in nature to provide a more accurate representation of the element's overall mass. Choice A, atomic number, represents the number of protons in an atom. Choice B, mass number, refers to the total number of protons and neutrons in an atom's nucleus. Choice D, neutron number, specifically focuses on the count of neutrons in an atom's nucleus. These choices do not directly relate to the average mass of isotopes as asked in the question.

5. The molar mass of some gases is as follows: carbon monoxide—28.01 g/mol; helium—4.00 g/mol; nitrogen—28.01 g/mol; and oxygen—32.00 g/mol. Which would you expect to diffuse most rapidly?

• A. Carbon monoxide
• B. Helium
• C. Nitrogen
• D. Oxygen

Correct answer: B

Rationale: The rate of diffusion is inversely proportional to the molar mass of the gas. Helium has the lowest molar mass among the given gases, making it the lightest and fastest gas to diffuse. Therefore, helium would be expected to diffuse most rapidly compared to carbon monoxide, nitrogen, and oxygen. Carbon monoxide, nitrogen, and oxygen have higher molar masses than helium, so they would diffuse more slowly. Therefore, the correct answer is helium.

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