Chemistry HESI A2 Quizlet

Correct Answer: C

Rationale: Group IIIA elements have 3 valence electrons, which they tend to lose to achieve a stable octet electron configuration. By losing 3 electrons, they acquire a +3 charge. This is why the correct answer is C. Choice A is incorrect because Group IIIA elements do not typically gain electrons to have a +1 charge. Choice B is incorrect as they don't lose 2 electrons to have a +2 charge. Choice D is incorrect as they do not gain or lose electrons to have a charge of 0.

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: +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 because a balanced chemical equation must satisfy the law of conservation of mass. This means that the number of atoms of each element must be the same on both the reactant and product sides. This ensures that no atoms are gained or lost during a chemical reaction. Explanation for why the other choices are incorrect: B: An equation with more products than reactants does not follow the law of conservation of mass. C: Balancing the number of molecules is important, but the key factor is balancing the number of atoms of each element. D: Equal masses on both sides do not necessarily guarantee that the number of atoms of each element is the same.

Correct Answer: B

Rationale: The correct answer is B: Solid. Solids have a definite shape and volume because the particles are closely packed and vibrate in fixed positions. Liquids (choice A) have a definite volume but not a definite shape as they take the shape of their container. Gases (choice C) have neither a definite shape nor volume as their particles are free to move around. Plasma (choice D) is a state of matter where particles are ionized, and it lacks a definite shape or volume. Therefore, the correct answer is B.