HESI A2 Chemistry

Correct Answer: B

Rationale: Failed to generate a rationale after 5 retries.

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: 19 protons. Potassium's atomic number is 19, which represents the number of protons in its nucleus. Protons are positively charged particles in an atom. Option A (18) is incorrect as it does not match the atomic number of Potassium. Options C (20) and D (21) are also incorrect as they do not correspond to Potassium's atomic number. Thus, the correct answer is B (19) based on the periodic table.

Correct Answer: B

Rationale: The correct answer is B (2). In a single covalent bond, two electrons are shared between two atoms to achieve a stable electron configuration. This sharing of electrons allows both atoms to fill their outermost electron shell and achieve a stable, lower energy state. This sharing of two electrons forms a single covalent bond. Explanation for other choices: A (1): One electron sharing would not be sufficient to form a stable covalent bond. C (3) and D (4): These options are incorrect because a single covalent bond involves the sharing of only two electrons, not three or four.

Correct Answer: C

Rationale: The correct balanced equation is 2Fe + O₂ → 2FeO. This is because there is 1 Fe atom on each side, 2 O atoms on each side, and the ratio of Fe to O is 2:2. Choice A has incorrect coefficients for Fe and O, choice B has an incorrect ratio of Fe to O, and choice D also has incorrect coefficients for Fe and O. Thus, the correct answer is C as it maintains the balance of atoms on both sides of the equation.