Chemistry HESI A2 Practice Test

Correct Answer: B

Rationale: The correct answer is B: Amalgam. An amalgam is an alloy where mercury (Hg) is the solvent and another metal is dissolved in it. This is a common dental material. Electrum (A) is a natural alloy of gold and silver. Solder (C) is a metal alloy used to join other metals. Bronze (D) is an alloy of copper and tin.

Correct Answer: A

Rationale: Failed to generate a rationale after 5 retries.

Correct Answer: B

Rationale: The correct answer is B: -1. In HCl, hydrogen is always assigned an oxidation state of +1. Since the overall charge of HCl is 0, the oxidation state of chlorine must be -1 to balance the charge. Chlorine is more electronegative than hydrogen and tends to gain an electron in this compound. Therefore, the oxidation state of the chlorine atom in HCl is -1. Choice A: +1 - Hydrogen is always assigned an oxidation state of +1 in compounds. Choice C: +2 - Chlorine does not have an oxidation state of +2 in HCl. Choice D: -2 - Chlorine's oxidation state is not -2 in HCl.

Correct Answer: D

Rationale: The correct answer is D: Xe. Xenon (Xe) is a noble gas, meaning it has a full outer electron shell, making it highly stable and least likely to react with other elements. Li (A) is a highly reactive alkali metal, Cr (B) is a transition metal with varying reactivities, and Nd (C) is a rare-earth metal that can exhibit reactivity. In summary, Xe is the least reactive as noble gases tend to be chemically inert due to their stable electron configuration.

Correct Answer: A

Rationale: The correct answer is A: 0 moles. In the given scenario, the volume of the solution is 0 L, which means there is no solution to contain any amount of salt. Molarity is the concentration of a solution in moles of solute per liter of solution. Since the volume is 0 L, there are no moles of salt present. Choice B, C, and D are incorrect because they suggest there are moles of salt present, which is not possible when the volume of the solution is 0 L.