Chemistry HESI A2 Quizlet

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.

Correct Answer: C

Rationale: The correct answer is C: Electronegativity. Polarity in a molecule is determined by the difference in electronegativity between atoms forming a bond. The greater the electronegativity difference, the more polar the bond and molecule. This is because electronegativity measures an atom's ability to attract electrons towards itself. Bond length (A) and bond strength (B) do not directly determine polarity, although shorter and stronger bonds can influence polarity indirectly. Molecular weight (D) is not a factor in determining polarity, as it relates to the total mass of a molecule rather than its polarity.

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.

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: B

Rationale: The correct answer is B: Alpha. Alpha radiation involves the emission of helium ions, which are essentially helium atoms that have lost two electrons. This type of radiation consists of alpha particles, which are positively charged and relatively heavy. They have low penetration power and can be stopped by a sheet of paper or human skin. Beta radiation (choice A) involves the emission of high-energy electrons or positrons, not helium ions. Gamma radiation (choice C) consists of electromagnetic waves and does not involve the emission of particles. There is no radiation type known as Delta (choice D). Therefore, the correct answer is B as it accurately describes the characteristics of alpha radiation.