Nursing Elites

1. 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.

2. Carbon-12 and carbon-14 are isotopes. What do they have in common?

• A. Number of nuclear particles
• B. Number of protons
• C. Number of neutrons
• D. Mass number

Correct answer: C

Rationale: Isotopes are atoms of the same element with the same number of protons (which determines the element) but different numbers of neutrons. Both carbon-12 and carbon-14 have 6 protons (hence they are both carbon atoms) but different numbers of neutrons: carbon-12 has 6 neutrons, while carbon-14 has 8 neutrons. Therefore, the correct answer is the number of neutrons. Choices A, B, and D are incorrect because isotopes may have different numbers of nuclear particles (protons + neutrons), protons, and mass numbers, respectively.

3. What is the charge of a beta particle?

• A. -1
• B. +1
• C. +2
• D. No charge

Correct answer: A

Rationale: A beta particle has a charge of -1. Beta particles are high-energy, high-speed electrons emitted during radioactive decay processes. Since electrons carry a charge of -1, beta particles also carry a charge of -1. This negative charge indicates that beta particles are negatively charged. Option B is incorrect as it suggests a positive charge, which is not the case for beta particles. Option C is incorrect as it indicates a higher positive charge, which is not true for beta particles. Option D is incorrect as beta particles do have a charge, which is negative.

4. How many neutrons are in an atom of carbon-12?

• A. 2
• B. 4
• C. 6
• D. 24

Correct answer: C

Rationale: An atom of carbon-12 has 6 neutrons. The atomic number of carbon is 6, representing the number of protons. The atomic mass of carbon-12 is 12. To find the number of neutrons, subtract the atomic number from the atomic mass: 12 - 6 = 6 neutrons. Choice A, 2, is incorrect as it does not reflect the correct calculation for neutrons in carbon-12. Choice B, 4, is incorrect as it does not match the correct number of neutrons in carbon-12. Choice D, 24, is incorrect as it is significantly higher than the actual number of neutrons in carbon-12.

5. Which ion would you expect to dominate in water solutions of bases?

• A. MgClâ‚‚
• B. 2HCl
• C. H⁺
• D. OH⁻

Correct answer: D

Rationale: In water solutions of bases, the dominant ion would be OH⁻ (hydroxide ion). Bases release OH⁻ ions when dissolved in water, increasing the concentration of hydroxide ions and leading to a higher pH. This is in contrast to acids, which release H⁺ ions. Therefore, in water solutions of bases, the presence of OH⁻ ions signifies the basic nature of the solution. Choices A, B, and C are incorrect because MgCl₂ is a salt, 2HCl is a compound consisting of two hydrogen ions and one chloride ion, and H⁺ represents a hydrogen ion typically associated with acids, not bases.

Similar Questions