HESI A2 Chemistry Questions

Correct Answer: B

Rationale: Failed to generate a rationale after 5 retries.

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: B

Rationale: The correct answer is B: joule. Joule is the SI unit of energy, defined as the work done when a force of one newton is applied over a distance of one meter. Ohm (A) is the SI unit of electrical resistance, henry (C) is the SI unit of inductance, and newton (D) is the SI unit of force. Therefore, the correct choice is B as it specifically represents energy in the SI system.

Correct Answer: D

Rationale: The correct answer is D: Baking soda. Baking soda, or sodium bicarbonate, has a pH value greater than 7, typically around 8.4 when dissolved in water. This is because it is a basic compound that releases hydroxide ions when dissolved in water, resulting in a pH above 7. In contrast, choices A, B, and C have pH values below 7. Water (choice A) is neutral with a pH of 7, vinegar (choice B) is acidic with a pH below 7, and lemon juice (choice C) is also acidic due to the presence of citric acid. Therefore, baking soda is the only substance among the choices that has a pH value greater than 7.

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.