HESI A2 Chemistry Practice Test

Correct Answer: D

Rationale: Boyle's Law states that the pressure of an ideal gas is inversely proportional to its volume when temperature and amount of gas are constant. This can be mathematically expressed as P1V1 = P2V2. As volume decreases, pressure increases and vice versa. Henry's Law relates gas solubility in liquids, Dalton's Law is about partial pressures of gases, and Brown's Law does not exist in the context of ideal gas laws. Thus, the correct answer is D (Boyle's Law).

Correct Answer: D

Rationale: Rationale: 1. Wavelength is defined as the distance between adjacent peaks or troughs on a wave. 2. Frequency is the number of wave cycles per unit time, not the distance between peaks/troughs. 3. Wavenumber is the spatial frequency of a wave, not the distance between peaks/troughs. 4. Wave oscillation refers to the movement of particles in a wave, not the distance between peaks/troughs. Summary: The correct answer is D because wavelength specifically refers to the distance between adjacent peaks or troughs on a wave, whereas the other choices are related to different properties of waves.

Correct Answer: A

Rationale: The correct answer is A because at high pressure and high temperature, real gases have increased kinetic energy and are closer together, leading to decreased intermolecular forces. This results in gas molecules behaving more like ideal gases with negligible volume and no intermolecular interactions. Choice B is incorrect because at low pressure, real gases have low kinetic energy and are far apart, causing intermolecular forces to become more significant, deviating from ideal behavior. Choice C is incorrect as the boiling point of water is a specific condition related to water and does not necessarily indicate ideal gas behavior. Choice D is incorrect because under certain conditions of high pressure and high temperature, real gases can approach ideal behavior, demonstrating that real gases can exhibit ideal behavior under specific circumstances.

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 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.