HESI A2 Chemistry Questions

Correct Answer: A

Rationale: The correct answer is A: Hydrogen acceptors. Bases or alkaline solutions are known as hydrogen acceptors because they can accept a hydrogen ion (H+) to form water. This process is known as neutralization. Choices B and C are incorrect because alkaline solutions are not solutions of low pH or hydrogen donors. Choice D, amphoteric, refers to substances that can act as both acids and bases, which is not the definition of bases or alkaline solutions.

Correct Answer: A

Rationale: The mass number is the sum of protons and neutrons in an atom. Given 6 protons and 6 neutrons, the mass number would be 6+6=12. Electrons do not contribute significantly to the mass number. Therefore, the correct answer is A: 12. Choice B is incorrect as it adds the protons, neutrons, and electrons together. Choice C only considers the number of protons. Choice D is incorrect as it only includes the number of protons.

Correct Answer: C

Rationale: The correct answer is C: aluminum. Specific heat capacity is the amount of heat required to raise the temperature of a unit mass of a substance by one degree Celsius. Aluminum has a small specific heat capacity compared to water, wood, and glass. This is because aluminum has a lower heat capacity due to its lower mass and atomic structure. Water, on the other hand, has a high specific heat capacity due to its hydrogen bonding, making it an excellent heat reservoir. Wood and glass have higher specific heat capacities compared to aluminum, as they are denser materials and require more heat energy to raise their temperatures.

Correct Answer: A

Rationale: The correct answer is A: Covalent bond. In a covalent bond, two atoms share electrons to complete their outer electron shells and achieve stability. This sharing results in a strong bond between the atoms. Ionic bonds involve the transfer of electrons, metallic bonds involve a "sea" of shared electrons in a metal lattice, and hydrogen bonds are weaker interactions between a hydrogen atom and an electronegative atom. Covalent bonds are the only option where electrons are shared between atoms to form a stable bond.

Correct Answer: A

Rationale: The correct answer is A: 7. In a neutral solution, the concentration of H+ ions equals the concentration of OH- ions, resulting in a pH of 7. This signifies a balance between acidity and alkalinity. Choice B (0) is incorrect as it represents a strong acid, choice C (14) is incorrect as it represents a strong base, and choice D (4) is incorrect as it indicates an acidic solution.