HESI A2 Chemistry Questions

Correct Answer: B

Rationale: The correct answer is B: Halogens. Halogens are a group of elements in Group 17 of the periodic table, including chlorine, fluorine, and iodine. They are known for their high reactivity and tendency to form salts with metals. Alkali metals (A) are in Group 1, transition metals (C) are in the middle part of the periodic table, and noble gases (D) are in Group 18. These choices are incorrect as they do not include chlorine, fluorine, and iodine, which are characteristic of the halogens.

Correct Answer: D

Rationale: The correct answer is D: Glucose. Glucose is a product of photosynthesis, as plants use sunlight, water, and carbon dioxide to produce glucose (sugar) and oxygen. Glucose is a type of carbohydrate that serves as a primary source of energy for plants and other organisms. Carbon dioxide (A) is one of the reactants needed for photosynthesis, not a product. Oxygen (B) is released as a byproduct of photosynthesis, not a product. Water (C) is also a reactant in photosynthesis, not a product. Therefore, the correct answer is D because glucose is the main product of photosynthesis.

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.

Correct Answer: A

Rationale: The correct answer is A: Synthesis reaction. In a synthesis reaction, two or more reactants combine to form a single product. This type of reaction is characterized by the formation of a more complex molecule from simpler ones. The other choices are incorrect because: B: Combustion reaction involves the rapid combination of a substance with oxygen, producing heat and light. C: Decomposition reaction involves the breakdown of a compound into simpler substances. D: Double displacement reaction involves the exchange of ions between two compounds to form two new compounds.

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.