Chemistry HESI A2 Quizlet

Correct Answer: B

Rationale: The correct answer is B (2). In a double covalent bond, two electron pairs are shared between two atoms. This is achieved by the sharing of two pairs of electrons, resulting in a total of four electrons being shared. However, since each pair consists of two electrons, the number of electron pairs shared to form a double covalent bond is 2. Choices A, C, and D are incorrect because a double bond involves the sharing of 2 electron pairs, not 1, 3, or 4 pairs.

Correct Answer: B

Rationale: The correct answer is B: Gas. Gases change in volume with changes in temperature and pressure according to the ideal gas law (PV = nRT). When temperature or pressure increases, gas molecules move faster and occupy more space, leading to an increase in volume. Liquids (choice A) have relatively fixed volumes, solids (choice C) have definite shapes and volumes, and plasmas (choice D) are ionized gases with unique properties but still do not change volume based on temperature and pressure changes.

Correct Answer: C

Rationale: The correct answer is C: Combustion. Combustion is a chemical reaction where a compound reacts with oxygen to produce heat, light, and often carbon dioxide and water. In this type of reaction, oxygen is a reactant and typically a hydrocarbon or organic compound is the fuel. Decomposition involves a compound breaking down into simpler substances, synthesis is when two or more substances combine to form a more complex compound, and single replacement is when one element replaces another in a compound. Combustion specifically involves the reaction with oxygen, making it the correct choice in this scenario.

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.

Correct Answer: A

Rationale: The correct answer is A: Chemical. In chemical reactions, atoms interact to achieve stable electron configurations through sharing, gaining, or losing electrons. This process involves forming chemical bonds to reach a more stable state, following the octet rule. Nuclear reactions involve changes in the nucleus, not electron configurations. Physical reactions involve changes in state or phase, not electron configurations. Mechanical reactions involve forces and motions, not electron configurations. Therefore, the correct choice is A as it directly pertains to atoms achieving stable electron configurations through chemical interactions.