HESI A2 Chemistry

Correct Answer: D

Rationale: The correct answer is D, H₂O. Water (H₂O) contains a polar covalent bond. This is because oxygen is more electronegative than hydrogen, creating an unequal sharing of electrons, resulting in a partial negative charge on oxygen and a partial positive charge on hydrogen. This polarity makes water a universal solvent and gives rise to properties like surface tension and hydrogen bonding. Choices A, B, and C (O, F, Br) do not form polar covalent bonds as they do not have significantly different electronegativities compared to the other element in the bond.

Correct Answer: C

Rationale: Step-by-step rationale: 1. Nonmetals are elements that lack metallic properties. 2. Sulfur is a nonmetal as it exists in a gaseous form at room temperature, lacks luster, and is a poor conductor of heat and electricity. 3. Mercury (A) is a metal as it is a liquid at room temperature. 4. Magnesium (B) and Potassium (D) are both metals as they are solid at room temperature and exhibit typical metallic properties. Summary: - A: Mercury is a metal. - B: Magnesium is a metal. - C: Sulfur is the correct answer as a nonmetal. - D: Potassium is a metal.

Correct Answer: D

Rationale: The correct answer is D, H₂O. Water (H₂O) contains a polar covalent bond. This is because oxygen is more electronegative than hydrogen, creating an unequal sharing of electrons, resulting in a partial negative charge on oxygen and a partial positive charge on hydrogen. This polarity makes water a universal solvent and gives rise to properties like surface tension and hydrogen bonding. Choices A, B, and C (O, F, Br) do not form polar covalent bonds as they do not have significantly different electronegativities compared to the other element in the bond.

Correct Answer: C

Rationale: Failed to generate a rationale after 5 retries.

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.