Chemistry HESI A2 Quizlet

Correct Answer: C

Rationale: The correct answer is C: Radiation. During radioactivity, particles such as alpha and beta particles, gamma rays, and positrons are emitted. These particles are collectively known as radiation. Electrons (choice A) and protons (choice B) are subatomic particles found in atoms and are not typically emitted during radioactivity. Neutrons (choice D) are neutral subatomic particles and are not emitted during radioactivity. Therefore, the correct answer is C as it encompasses the various types of particles emitted during radioactive decay.

Correct Answer: D

Rationale: The correct answer is D: Molar mass. One mole of a substance represents the molar mass, which is the mass of one mole of that substance in grams. This is calculated by summing the atomic masses of all the atoms in the chemical formula. The molar mass is expressed in g/mol and is a fundamental concept in chemistry for performing various calculations. A: Atomic mass refers to the mass of an individual atom of an element, not one mole of a substance. B: Mass number refers to the total number of protons and neutrons in an atom's nucleus, not the mass of one mole of a substance. C: Molecular weight is the sum of the atomic weights of the atoms in a molecule, not the mass of one mole of a substance.

Correct Answer: A

Rationale: The correct answer is A: 6.02 x 10^23. A mole is a unit used in chemistry to represent a specific number of particles, which is Avogadro's number, approximately 6.02 x 10^23. This number represents the number of atoms, ions, or molecules in one mole of a substance. It is a fundamental concept in chemistry for measuring quantities of substances. Choices B, C, and D have incorrect values for Avogadro's number, so they do not represent the correct definition of a mole.

Correct Answer: B

Rationale: Dispersion forces are the weakest intermolecular forces present in non-polar covalent compounds due to temporary dipoles. Non-polar compounds have symmetrical distribution of electrons, leading to temporary shifts in electron density causing dispersion forces. Polar compounds (choice A) have permanent dipoles, ionic compounds (choice C) have strong electrostatic forces, and hydrogen compounds (choice D) involve hydrogen bonding - all of which are stronger than dispersion forces and not typically found in non-polar compounds. Therefore, the correct answer is B - non-polar covalent compounds.

Correct Answer: B

Rationale: The correct answer is B, the Law of Conservation of Mass. This law states that matter cannot be created or destroyed in a chemical reaction, only rearranged. This is based on the principle of mass conservation, where the total mass of the reactants equals the total mass of the products. This law is supported by experimental evidence and is a fundamental principle in chemistry. Choice A, the Law of Conservation of Energy, is incorrect because it pertains to the conservation of energy, not mass. Choice C, the Law of Constant Composition, is incorrect as it refers to compounds having fixed ratios of elements. Choice D, the Law of Multiple Proportions, is incorrect because it describes the ratios in which elements combine to form different compounds, not the conservation of mass.