Chemistry HESI A2 Quizlet

Correct Answer: B

Rationale: The correct answer is B: Single replacement. In this type of reaction, an active metal replaces another metal in an ionic compound, forming a new compound. This is due to the reactivity of the active metal displacing the less reactive metal in the compound. Combustion (choice A) involves a substance reacting with oxygen to produce heat and light. Synthesis (choice C) is the combination of two or more substances to form a new compound. Decomposition (choice D) is when a compound breaks down into simpler substances. In this scenario, single replacement best fits the description of an active metal reacting with an ionic compound to create a new compound.

Correct Answer: A

Rationale: The correct answer is A: Neutrons. Neutrons are neutral particles because they have no charge, unlike protons (positively charged), electrons (negatively charged), and cations (positively charged ions). Neutrons are found in the nucleus of an atom along with protons, contributing to the atomic mass without affecting the overall charge. This makes them essential for maintaining the stability of the nucleus. Therefore, neutral particles are called neutrons.

Correct Answer: B

Rationale: The sum of protons and neutrons in an element represents the mass number. Protons and neutrons are located in the nucleus and contribute to the mass of an atom. The atomic number (A) is the number of protons in an atom, not the sum of protons and neutrons. Atomic mass (C) is the average mass of an element's isotopes, considering their abundance, and is not the sum of protons and neutrons. Neutron number (D) refers to the specific number of neutrons in an atom, not the total mass of the nucleus. Therefore, the correct answer is B, as it accurately represents the total mass of an atom.

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: Stoichiometry is the study of mass relationships in chemical reactions. It involves calculating the quantities of reactants and products. By using balanced chemical equations, one can determine the amounts of substances involved. This answer is correct because it directly relates to the main concept of stoichiometry. Explanation for other choices: A: The study of energy changes in chemical reactions - This is incorrect as it refers to the field of thermodynamics. C: The study of atomic structure - This is incorrect as it pertains to atomic theory and not the mass relationships in reactions. D: The study of molecular geometry - This is incorrect as it deals with the spatial arrangement of atoms in molecules, not the mass relationships in reactions.