HESI A2 Chemistry Questions

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: 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: B

Rationale: The correct answer is B: It releases heat. In an exothermic reaction, energy is released in the form of heat to the surroundings. This results in a temperature increase in the surrounding environment. The other choices are incorrect because: A: It absorbs heat - This is a characteristic of an endothermic reaction, where heat is absorbed from the surroundings. C: It remains neutral - This does not describe the nature of an exothermic reaction, which involves the release of heat. D: It requires energy input - This is more in line with an endothermic reaction, where energy input is needed to drive the reaction.

Correct Answer: A

Rationale: The correct answer is A: Decomposition reaction. In a decomposition reaction, a compound is broken down into its individual components. This process involves the breaking of chemical bonds within the compound, resulting in the formation of simpler substances. This type of reaction is characterized by one reactant and multiple products. In contrast, the other choices - B: Combustion reaction, C: Neutralization reaction, and D: Single displacement reaction - do not involve the breaking down of a compound into its components but rather involve different types of chemical transformations. Combustion reaction involves the reaction of a substance with oxygen to produce heat and light, neutralization reaction involves the reaction between an acid and a base to form water and a salt, and single displacement reaction involves the replacement of one element in a compound by another element.

Correct Answer: D

Rationale: The correct answer is D: High specific heat. Water's ability to form hydrogen bonds allows it to absorb and retain a significant amount of heat before its temperature changes. This property is essential for regulating temperature in living organisms and maintaining stable environments. A: Lack of cohesiveness - This is incorrect because water's hydrogen bonding actually promotes cohesion, leading to high surface tension. B: Low surface tension - This is incorrect because water's hydrogen bonding contributes to high surface tension. C: Use as a nonpolar solvent - This is incorrect because water is a polar solvent, not nonpolar, due to its hydrogen bonding capabilities.