HESI A2 Chemistry

Correct Answer: C

Rationale: Failed to generate a rationale after 5 retries.

Correct Answer: C

Rationale: The molar mass of sodium chloride (NaCl) is calculated by adding the atomic masses of sodium (Na) and chlorine (Cl) together. Sodium has an atomic mass of approximately 23 g/mol, and chlorine has an atomic mass of approximately 35.5 g/mol. Adding these two values gives a molar mass of 58.5 g/mol for sodium chloride. Rounding to the nearest whole number, the mass of one mole of sodium chloride is 58 g/mol, which corresponds to choice C. Choices A, B, and D are incorrect as they do not accurately reflect the molar mass of sodium chloride. Option A is close but slightly lower than the correct value, while options B and D are significantly off.

Correct Answer: B

Rationale: The correct answer is B: London dispersion force. This is because London dispersion forces are the weakest intermolecular force, resulting in lower boiling points compared to the other options. London dispersion forces are temporary, induced forces caused by momentary fluctuations in electron distribution within molecules. Dipole-dipole interactions (A), Keesom interactions (C), and hydrogen bonding (D) are stronger intermolecular forces that require specific molecular properties such as permanent dipoles or hydrogen bonding, leading to higher boiling points. Therefore, London dispersion forces would result in the lowest boiling point among the options provided.

Correct Answer: B

Rationale: The correct answer is B: Butane. In this compound, CH₃-CH₂-CH₂-CH₃, there are four carbon atoms connected in a straight chain, making it a butane. The prefix "but-" indicates that there are four carbon atoms, and the suffix "-ane" indicates that the compound contains only single bonds between the carbon atoms. Therefore, the correct name is Butane. Choice A: Cyclobutane is incorrect because it would be a cyclic compound with four carbon atoms forming a ring. Choice C: Butene is incorrect because it would have a double bond between two carbon atoms, making it an alkene. Choice D: Butyne is incorrect because it would have a triple bond between two carbon atoms, making it an alkyne.

Correct Answer: B

Rationale: The correct answer is B: Acid. Acids are hydrogen or proton donors, corrosive to metals, turn blue litmus paper red (indicating acidity), and become less acidic when mixed with a base due to neutralization reaction. Bases (choice A) are proton acceptors and do not exhibit these characteristics. Salts (choice C) are formed from the reaction between an acid and a base and do not fit all the given criteria. Hydroxides (choice D) are bases and do not donate protons or exhibit the acidic properties described.