Chemistry HESI A2 Quizlet

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: C

Rationale: Increasing the surface area of a reactant increases the number of exposed particles available for collision, leading to more frequent and successful collisions. This results in an increased reaction rate. Choice A is incorrect because more surface area facilitates faster reactions. Choice B is incorrect as surface area affects reaction rate. Choice D is incorrect as increasing surface area does not stop the reaction; it actually accelerates it.

Correct Answer: C

Rationale: The correct answer is C: Anions. Negatively charged ions are referred to as anions because they have gained extra electrons, resulting in a negative charge. Neutrons (A) are neutral particles found in the nucleus of an atom. Protons (B) are positively charged particles found in the nucleus. Cations (D) are positively charged ions that have lost electrons. Therefore, based on the definition of negatively charged ions, anions are the correct choice.

Correct Answer: B

Rationale: The correct answer is B because hydrogen bonding, dipole interactions, and dispersion forces are the three types of intermolecular forces. Hydrogen bonding occurs between molecules with a hydrogen atom bonded to a highly electronegative atom. Dipole interactions arise from the attraction between polar molecules. Dispersion forces are the weakest intermolecular forces and occur due to temporary fluctuations in electron distribution. Choices A, C, and D are incorrect because they do not accurately represent the three specific types of intermolecular forces.

Correct Answer: C

Rationale: The correct answer is C, atomic number. The atomic number represents the number of protons in an element. This is because the atomic number is the unique identifier of an element and determines its chemical properties. Protons are the positively charged particles in the nucleus of an atom, and the number of protons defines the element's identity. Explanation for incorrect choices: A: Atomic mass represents the average mass of all isotopes of an element, not the number of protons. B: Mass number is the sum of protons and neutrons in an atom, not just the number of protons. D: "Proton number" is not a standard term in chemistry, and it does not specifically refer to the number of protons in an element.