Chemistry HESI A2 Practice Test

Correct Answer: C

Rationale: To calculate molarity, we need to find the number of moles of solute (glucose) and the volume of the solution. 1. Calculate moles of glucose: 5g / 180 g/mol = 0.0278 mol 2. Calculate total mass of the solution: 5g (glucose) + 100g (water) = 105g 3. Calculate molarity: 0.0278 mol / 0.105 kg = 0.2667 M ≈ 2.8M (Choice C) Rationale: Molarity is moles of solute per liter of solution. The correct answer is C because it correctly calculates the molarity of the solution. Other choices are incorrect as they do not provide the accurate molarity value based on the given information.

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: C

Rationale: The correct answer is C: Polar covalent and ionic. When an acid reacts with a base, water and a salt are produced. In water, the bonds between hydrogen and oxygen are polar covalent due to the electronegativity difference between the two atoms. In the salt formed, the bond between the cation and anion is ionic, as one atom donates electrons to the other, resulting in a strong electrostatic attraction. Choice A (Liquid and metallic) is incorrect as it does not describe the bonds formed in water and the salt. Choice B (Polar and nonpolar covalent) is incorrect because nonpolar covalent bonds do not form in this scenario. Choice D (Ionic only) is incorrect because water forms polar covalent bonds, in addition to the ionic bonds in the salt.

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: B

Rationale: Failed to generate a rationale after 5 retries.