Chemistry HESI A2 Quizlet

Correct Answer: B

Rationale: The correct answer is B: Double replacement. In this type of reaction, two ionic compounds swap ions to form two new compounds. The cations and anions switch partners, leading to the formation of two different ionic compounds. This process is also known as metathesis. Single replacement (A) involves an element replacing another in a compound. Synthesis (C) involves the combination of two or more substances to form a single compound. Decomposition (D) involves a single compound breaking down into simpler substances. Double replacement is the only option where two ionic compounds exchange partners, making it the correct choice in this scenario.

Correct Answer: C

Rationale: The correct answer is C: Atomic mass. Atomic mass refers to the average mass of an element's isotopes as they occur in nature. This is calculated by taking into account the abundance of each isotope. The atomic number (A) is the number of protons in an atom's nucleus, not the average mass. The mass number (B) is the sum of protons and neutrons in an atom's nucleus, not the average mass. Neutron number (D) is simply the number of neutrons in an atom's nucleus, not the average mass. Therefore, the correct term for the average mass of isotopes is atomic mass.

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.

Correct Answer: B

Rationale: The correct answer is B: Physical. When no change is made to the chemical composition of a substance, it indicates a physical change. In physical changes, the substance retains its chemical identity and only its physical properties, such as shape, size, and state, are altered. This is because the particles in the substance rearrange or move without forming new substances. Choice A (Chemical) involves a change in the chemical composition, so it is incorrect. Choice C (Nuclear) involves changes at the atomic level, leading to different elements, which is not the case here. Choice D (Mechanical) involves changes in position and motion of objects, not relevant to the chemical composition of a substance.

Correct Answer: D

Rationale: The correct answer is D: Color of the reactants. The color of the reactants does not affect the reaction rate as it is a purely visual characteristic and does not influence the speed at which the reaction occurs. Temperature affects reaction rate by providing energy for molecules to react faster. Surface area influences reaction rate by increasing the area of contact between reactants. Concentration of reactants affects reaction rate by increasing the frequency of collisions between molecules. In summary, factors like temperature, surface area, and concentration directly impact reaction rate, whereas color is merely a visual property and does not play a role in determining the speed of a chemical reaction.