Chemistry HESI A2 Quizlet

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.

Correct Answer: A

Rationale: The Group IA elements, also known as alkali metals, have a +1 charge. This is because they have one valence electron, which they readily lose to achieve a stable electron configuration. This results in them forming ions with a +1 charge. Therefore, the correct answer is A. Choice B (+2) is incorrect because alkali metals do not typically form ions with a +2 charge due to their tendency to lose only one electron. Choice C (+3) is also incorrect as alkali metals do not form ions with a +3 charge. Choice D (0) is incorrect because alkali metals are known for their tendency to lose electrons to achieve a stable configuration, resulting in a positive charge.

Correct Answer: A

Rationale: The correct answer is A: 1. In a single bond, only one pair of electrons is shared between two atoms, resulting in a stable bond. This shared pair of electrons creates a strong attraction between the atoms, holding them together. The other choices (B, C, D) are incorrect as they represent the number of pairs of electrons shared in double, triple, or quadruple bonds, respectively, which involve 2, 3, or 4 pairs of electrons being shared, not in a single bond. Thus, the correct answer is A because a single bond involves only one pair of shared electrons.

Correct Answer: A

Rationale: The correct answer is A: Hydrogen and oxygen. Water decomposes into hydrogen and oxygen through a process called electrolysis. In this process, an electric current is passed through water, causing it to break down into its constituent elements. Hydrogen is produced at the cathode, while oxygen is produced at the anode. This is a well-known and scientifically proven reaction. Choices B, C, and D are incorrect because water does not decompose into carbon dioxide, nitrogen, or methane under normal conditions. This can be confirmed by studying the chemical properties and reactions of water.

Correct Answer: A

Rationale: The correct answer is A: Polar. In a covalent bond, if electrons are not shared equally, the bond is considered polar. This occurs when one atom has a higher electronegativity than the other, leading to an uneven distribution of electron density. As a result, one end of the bond will have a partial negative charge while the other end will have a partial positive charge, creating a dipole moment. Choices B (Non-polar) and D (Hydrogen) are incorrect because they do not specifically address the unequal sharing of electrons in a covalent bond. Choice C (Ionic) is incorrect as ionic bonds involve the complete transfer of electrons, not sharing.