Chemistry HESI A2 Practice Test

Correct Answer: C

Rationale: The correct answer is C: +2. An alpha particle consists of two protons and two neutrons, giving it a total charge of +2. Protons have a charge of +1 each, and neutrons have no charge. Therefore, the total charge of an alpha particle is +2. Choice A (-1) is incorrect because it is the charge of an electron. Choice B (+1) is incorrect because it represents the charge of a proton. Choice D (No charge) is incorrect because alpha particles have a positive charge due to the presence of protons.

Correct Answer: B

Rationale: The correct answer is B: Days-long. Medical isotopes used in medicine typically have a short half-life to minimize radiation exposure to patients. A days-long half-life strikes a balance between decay rate and practical usability in medical procedures. Choice A (Seconds-long) would be too short for practical use. Choices C (Years-long) and D (Many years long) would result in prolonged radiation exposure, increasing health risks for patients.

Correct Answer: D

Rationale: The correct name of AgNO₃ is Silver nitrate (D) because it follows the naming conventions for ionic compounds. "Silver" is the cation (Ag⁺) and "nitrate" is the anion (NO₃⁻), so the compound is named as "Silver nitrate." A: Argent nitrous - Incorrect, "argent" refers to silver but "nitrous" is incorrect for the nitrate ion. B: Argent oxide - Incorrect, "oxide" refers to O²⁻ ion, not NO₃⁻. C: Silver nitrite - Incorrect, "nitrite" is different from "nitrate," so the name is incorrect.

Correct Answer: C

Rationale: The correct answer is C: Fluorine. Fluorine is not an allotrope of carbon because allotropes are different forms of the same element. Fluorine is a different element altogether. Diamond, graphite, and buckminsterfullerene are all allotropes of carbon, each with unique molecular structures and properties. Diamond has a tetrahedral structure, graphite has layers of hexagonal rings, and buckminsterfullerene has a spherical shape. Fluorine, on the other hand, is a diatomic molecule consisting of two atoms of fluorine bonded together. Therefore, C is the correct answer as it does not belong to the category of carbon allotropes.

Correct Answer: C

Rationale: The correct answer is C: +2. An alpha particle consists of two protons and two neutrons, giving it a total charge of +2. Protons have a charge of +1 each, and neutrons have no charge. Therefore, the total charge of an alpha particle is +2. Choice A (-1) is incorrect because it is the charge of an electron. Choice B (+1) is incorrect because it represents the charge of a proton. Choice D (No charge) is incorrect because alpha particles have a positive charge due to the presence of protons.