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: Stoichiometry. Stoichiometry is the branch of chemistry that deals with the quantitative relationships between reactants and products in a chemical reaction. It involves calculating the amount of substances consumed and produced in a reaction based on balanced chemical equations. This includes determining the mole ratios, mass relationships, and volume relationships in a reaction. Choice B (Molecular chemistry) focuses on the structure and properties of molecules, not specifically on quantities in reactions. Choice C (Atomic chemistry) deals with the study of atoms and their properties, not the quantities in reactions. Choice D (Thermodynamics) concerns energy changes in chemical reactions, not the quantitative relationships between compounds. Therefore, stoichiometry is the correct choice for this question.

Correct Answer: B

Rationale: The correct answer is B because hydrogen bonding, dipole interactions, and dispersion forces are the three types of intermolecular forces. Hydrogen bonding occurs between molecules with a hydrogen atom bonded to a highly electronegative atom. Dipole interactions arise from the attraction between polar molecules. Dispersion forces are the weakest intermolecular forces and occur due to temporary fluctuations in electron distribution. Choices A, C, and D are incorrect because they do not accurately represent the three specific types of intermolecular forces.

Correct Answer: B

Rationale: The correct answer is B: +2. Group IIA elements have a valence of +2 because they have 2 valence electrons in their outer shell. These elements lose these 2 electrons to achieve a stable octet configuration, resulting in a +2 charge. Choice A is incorrect because Group IIA elements do not have a charge of 1. Choice C is incorrect because Group IIA elements do not typically have a negative charge of -3. Choice D is incorrect because Group IIA elements do not have a charge of 0; they lose 2 electrons to become positively charged.

Correct Answer: A

Rationale: The correct answer is A: Periods. Periods are the horizontal rows in the periodic table that represent the number of electron shells an element has. Each period corresponds to the principal energy level of the element. Families (Choice B) are the vertical columns of the periodic table that share similar properties. Groups (Choice C) are also vertical columns that share similar chemical properties. Columns (Choice D) are not a term used in the context of the periodic table. Therefore, the correct term for the horizontal rows in the periodic table is periods.