HESI A2 Chemistry Practice Test

Correct Answer: A

Rationale: The correct answer is A: Order of increasing atomic number. This is because the periodic table is arranged based on the number of protons in the nucleus of an atom, which is the atomic number. This arrangement helps in organizing elements based on their properties and allows us to predict the behavior of elements. Choice B (Alphabetical order) is incorrect because elements are not arranged alphabetically but based on their atomic number. Choice C (Order of increasing metallic properties) is incorrect because while elements are grouped based on similar properties, the overall arrangement is not solely based on metallic properties. Choice D (Order of increasing neutron content) is incorrect as the periodic table is based on atomic number (number of protons), not neutron content.

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: Covalent bonds. Covalent bonds involve a complete sharing of electrons between atoms with partially filled outer shells. This sharing allows atoms to achieve stable electron configurations. Hydrogen bonds involve an electrostatic attraction between a hydrogen atom and a highly electronegative atom. Proportional bonds are not a recognized type of chemical bond. Choice D, N/A, is not a valid option for this question.

Correct Answer: C

Rationale: The statement that the volume of a gas is directly proportional to its absolute temperature at constant pressure aligns with Charles' Law. This law states that for a fixed amount of gas at a constant pressure, the volume of the gas is directly proportional to its absolute temperature. As the temperature increases, the volume of the gas also increases proportionally. This relationship is depicted by the equation V1/T1 = V2/T2. The other choices are incorrect because the Combined Gas Law involves pressure, volume, and temperature changes simultaneously; Boyle's Law describes the inverse relationship between pressure and volume at constant temperature, and the Ideal Gas Law is a combination of Boyle's, Charles', and Avogadro's Laws.

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.