Chemistry HESI A2 Practice Test

Correct Answer: D

Rationale: Step 1: Define hydrogen bonding as a special type of dipole-dipole interaction. Step 2: Highlight that hydrogen bonding occurs between a hydrogen atom and highly electronegative atom (N, O, or F). Step 3: Emphasize that hydrogen bonding is stronger due to the large electronegativity difference between hydrogen and the other atom. Step 4: Compare the strength of hydrogen bonding to the other types of intermolecular forces. Step 5: Conclude that hydrogen bonding is the strongest intermolecular force due to its specific characteristics and stronger attraction compared to dipole-dipole interaction, London dispersion force, and Keesom interaction.

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.

Correct Answer: A

Rationale: The correct answer is A because the rate of diffusion is inversely proportional to the square root of the molar mass. Therefore, if gas A has four times the molar mass of gas B, gas A would diffuse at half the rate of gas B. This is because the square root of 4 is 2, indicating that gas A would diffuse at a rate that is half of gas B. Choice B is incorrect because if gas A has four times the molar mass of gas B, it would not diffuse at twice the rate of gas B. Choice C is incorrect because gas A would not diffuse at a quarter the rate of gas B. Choice D is incorrect because gas A would not diffuse at four times the rate of gas B.

Correct Answer: B

Rationale: The correct formula for silver hydroxide is AgOH. Silver is a transition metal with a +1 charge, and hydroxide is OH⁻. To balance the charges, one silver ion combines with one hydroxide ion to form AgOH. Choice A (AgO) is incorrect because it does not include the hydroxide ion. Choice C (AgH) is incorrect as it suggests silver bonding with hydrogen, which is not the case. Choice D (AgH₂O) is incorrect as it implies silver bonding with water molecules, which is not the formula for silver hydroxide.

Correct Answer: B

Rationale: The correct answer is B: 8. Carbon-14 has 6 protons, so to find the number of neutrons, subtract the atomic number from the atomic mass. Carbon-14 has an atomic mass of approximately 14, so 14 (atomic mass) - 6 (protons) = 8 neutrons. Choice A (10) is incorrect because it doesn't correspond to the correct calculation for carbon-14. Choice C (6) is the number of protons, not neutrons. Choice D (12) is incorrect as it does not align with the calculated number of neutrons in carbon-14.