HESI A2 Chemistry Practice Test

Correct Answer: D

Rationale: Rationale: 1. Statement A is correct as solubility is indeed defined by the concentration in a saturated solution. 2. Statement B is correct as substances with very low solubilities are typically considered insoluble. 3. Statement C is correct as a saturated solution cannot dissolve any more solute. 4. Therefore, all statements (A, B, and C) are correct, making option D the correct choice. Other options are incorrect as they do not accurately define solubility or saturated solutions.

Correct Answer: B

Rationale: The correct answer is B because glycogen is a type of starch that is primarily found in animals, particularly in their liver and muscles, serving as a storage form of glucose. Plant starches (choice A) are primarily found in plants, not animals. Glucose (choice C) is a simple sugar molecule, not a type of starch. Cellulose (choice D) is a structural polysaccharide found in plant cell walls, not a storage form of glucose like glycogen. Therefore, the correct answer is B, as glycogen is indeed an animal starch.

Correct Answer: C

Rationale: The correct answer is C: Frequency. Frequency is defined as the number of cycles of a wave that move past a fixed observation point per second. It is measured in Hertz (Hz). Frequency determines the pitch of a sound wave and the color of light. Choice A, Wave, is the general term for a disturbance that travels through a medium. Choice B, Wavelength, is the distance between two consecutive points on a wave that are in phase. Choice D, Wavefunction, is a mathematical function that describes the wave-like behavior of a particle in quantum mechanics.

Correct Answer: B

Rationale: The correct answer is B: -2. In most compounds, oxygen has an oxidation number of -2 due to its high electronegativity. Oxygen typically gains electrons in chemical reactions. This is consistent with the octet rule, where oxygen achieves a stable electron configuration by gaining two electrons. Choices A, C, and D are incorrect as oxygen rarely has an oxidation number of 2, 0, or -1 in compounds. Oxygen's oxidation number is -2 in the majority of cases, making choice B the correct answer.

Correct Answer: B

Rationale: The typical oxidation state of oxygen in most compounds is -2. Oxygen is highly electronegative and tends to gain 2 electrons to achieve a stable octet configuration. This results in an oxidation state of -2 in compounds like water (H2O) and carbon dioxide (CO2). Therefore, choice B is correct. Choice A (-1) is incorrect because oxygen rarely has an oxidation state of -1 in compounds. Choice C (0) is incorrect as oxygen doesn't usually have an oxidation state of 0; it prefers to gain electrons. Choice D (-3) is incorrect as it is an uncommon oxidation state for oxygen in compounds.