HESI A2 Chemistry Practice Test

Correct Answer: C

Rationale: The correct answer is C: Representative elements. S block and p block elements collectively make up the representative elements in the periodic table. S block elements are the alkali metals and alkaline earth metals, while p block elements include nonmetals, metalloids, and halogens. These elements are called representative elements because they represent the diverse chemical properties found in the periodic table. Transition elements (A) are the d block elements, not the s and p block elements. Active elements (B) and inactive elements (D) are not specific terms used to categorize elements in the periodic table.

Correct Answer: A

Rationale: The correct answer is A because at high pressure and high temperature, real gases have increased kinetic energy and are closer together, leading to decreased intermolecular forces. This results in gas molecules behaving more like ideal gases with negligible volume and no intermolecular interactions. Choice B is incorrect because at low pressure, real gases have low kinetic energy and are far apart, causing intermolecular forces to become more significant, deviating from ideal behavior. Choice C is incorrect as the boiling point of water is a specific condition related to water and does not necessarily indicate ideal gas behavior. Choice D is incorrect because under certain conditions of high pressure and high temperature, real gases can approach ideal behavior, demonstrating that real gases can exhibit ideal behavior under specific circumstances.

Correct Answer: C

Rationale: The correct answer is C: Boyle. Boyle's Law states that the pressure and volume of a gas are inversely proportional when temperature is constant. Boyle conducted experiments that led to this discovery. Choice A, Charles, is known for Charles's Law which relates volume and temperature. Choice B, Combine, is not a known scientist. Choice D, Gay-Lussac, is known for Gay-Lussac's Law which relates pressure and temperature.

Correct Answer: D

Rationale: Rationale: 1. Statement A is correct as solubility is indeed defined by the concentration in a saturated solution. 2. Statement B is correct as substances with very low solubilities are typically considered insoluble. 3. Statement C is correct as a saturated solution cannot dissolve any more solute. 4. Therefore, all statements (A, B, and C) are correct, making option D the correct choice. Other options are incorrect as they do not accurately define solubility or saturated solutions.

Correct Answer: B

Rationale: The correct answer is B. Temperature affects reaction rates by increasing kinetic energy. Particle size influences surface area available for collision. Concentration impacts frequency of collisions. Catalysts lower activation energy. Barometric pressure, container material, elevation, and volatility do not directly affect reaction rates. Option A includes "barometric pressure" and "facilitator," which are irrelevant. Option C includes "container material" and "elevation," which are not factors. Option D includes "volatility," which is not typically a factor in rates of reaction.