HESI A2 Chemistry

Correct Answer: B

Rationale: Failed to generate a rationale after 5 retries.

Correct Answer: C

Rationale: The correct answer is C: 6. In an atom of carbon-12, the atomic number (number of protons) is 6. Since the atomic number represents the number of protons, to find the number of neutrons, we subtract the atomic number from the mass number. Carbon-12 has a mass number of 12, so 12 - 6 = 6 neutrons. Other choices are incorrect because: A: 2 - This is not correct because the number of neutrons is not equal to the atomic number in carbon-12. B: 4 - This is incorrect as it does not consider the correct calculation based on the atomic number and mass number. D: 24 - This answer is incorrect as it is not related to the atomic structure of carbon-12.

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: Failed to generate a rationale after 5 retries.

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.