HESI A2 Chemistry Questions

Correct Answer: B

Rationale: The correct answer is B: Group 1 contains the alkali metals. Alkali metals are found in Group 1 because they have a single valence electron, making them highly reactive. They exhibit similar properties due to the presence of this single electron. Group 7 contains the halogens and is known for its high reactivity. Group 2 contains the alkaline earth metals, which have two valence electrons. Group 3 contains the transition metals, which have varying numbers of valence electrons and are less reactive compared to alkali metals. Thus, Group 1 is the only group that fits the characteristics of alkali metals.

Correct Answer: A

Rationale: The correct answer is A: Hydrogen acceptors. Bases or alkaline solutions are known as hydrogen acceptors because they can accept a hydrogen ion (H+) to form water. This process is known as neutralization. Choices B and C are incorrect because alkaline solutions are not solutions of low pH or hydrogen donors. Choice D, amphoteric, refers to substances that can act as both acids and bases, which is not the definition of bases or alkaline solutions.

Correct Answer: C

Rationale: The correct answer is C: aluminum. Specific heat capacity is the amount of heat required to raise the temperature of a unit mass of a substance by one degree Celsius. Aluminum has a small specific heat capacity compared to water, wood, and glass. This is because aluminum has a lower heat capacity due to its lower mass and atomic structure. Water, on the other hand, has a high specific heat capacity due to its hydrogen bonding, making it an excellent heat reservoir. Wood and glass have higher specific heat capacities compared to aluminum, as they are denser materials and require more heat energy to raise their temperatures.

Correct Answer: B

Rationale: The correct answer is B: Fluorine. Halogens are a group of elements in the periodic table that include Fluorine, Chlorine, Bromine, Iodine, and Astatine. They are highly reactive nonmetals with seven valence electrons, making them very electronegative. Fluorine specifically is the most reactive and electronegative element, commonly found in compounds like fluoride toothpaste. A: Oxygen is not a halogen. It is a nonmetal but belongs to the chalcogen group in the periodic table. C: Sodium is a metal and belongs to the alkali metal group, not a halogen. D: Carbon is a nonmetal but is not a halogen. It belongs to the p-block elements on the periodic table.

Correct Answer: A

Rationale: The correct answer is A: A reaction that absorbs heat. Endothermic reactions absorb heat from their surroundings, causing a decrease in temperature. This is due to the breaking of chemical bonds which requires energy input. Choice B is incorrect as exothermic reactions release heat. Choice C is incorrect as all reactions involve heat to some extent. Choice D is incorrect as endothermic reactions result in a decrease in temperature due to heat absorption.