HESI A2 Chemistry

Correct Answer: C

Rationale: Failed to generate a rationale after 5 retries.

Correct Answer: C

Rationale: Step-by-step rationale: 1. Nonmetals are elements that lack metallic properties. 2. Sulfur is a nonmetal as it exists in a gaseous form at room temperature, lacks luster, and is a poor conductor of heat and electricity. 3. Mercury (A) is a metal as it is a liquid at room temperature. 4. Magnesium (B) and Potassium (D) are both metals as they are solid at room temperature and exhibit typical metallic properties. Summary: - A: Mercury is a metal. - B: Magnesium is a metal. - C: Sulfur is the correct answer as a nonmetal. - D: Potassium is a metal.

Correct Answer: B

Rationale: To prepare a 0.100 M solution, we use the formula M1V1 = M2V2. Given M1=concentration of concentrated HCl, V1=volume of concentrated HCl, M2=desired concentration, V2=final volume. Plugging in the values, we get M1(unknown volume) = 0.100 M x 500 mL. Solving for the unknown volume, we find V1 = (0.100 M x 500 mL) / M1. As we want to find the volume of concentrated HCl needed, we isolate V1. Therefore, V1 = 100 mL. This corresponds to choice B as the correct answer. Choices A, C, and D are incorrect as they do not match the calculated volume needed to prepare the 0.100 M HCl solution.

Correct Answer: B

Rationale: The correct answer is B: Alpha, Beta, Gamma. - Alpha radiation consists of helium nuclei. - Beta radiation consists of high-energy electrons or positrons. - Gamma radiation is electromagnetic radiation. Alpha, Beta, and Gamma are the three most common types of radiation in nuclear chemistry. Choice A is incorrect because "Delta" is not a type of radiation in nuclear chemistry. Choice C is incorrect because "Delta" is not a type of radiation, and the order is incorrect. Choice D is incorrect because "Delta" is not a type of radiation, and the order is incorrect.

Correct Answer: D

Rationale: The correct answer is D: W (tungsten). Tungsten has the greatest atomic mass among the elements listed. Tungsten has an atomic number of 74, which corresponds to an atomic mass of approximately 183.84 g/mol. Gold (Au) has an atomic number of 79, with an atomic mass of around 196.97 g/mol, making it heavier than barium (Ba) and iodine (I). Barium has an atomic number of 56, with an atomic mass of about 137.33 g/mol, and iodine has an atomic number of 53, with an atomic mass of roughly 126.90 g/mol. Therefore, tungsten (W) has the greatest atomic mass compared to the other elements listed.