Chemistry HESI A2 Quizlet

Correct Answer: C

Rationale: The correct answer is C: Combustion. Combustion is a chemical reaction where a compound reacts with oxygen to produce heat, light, and often carbon dioxide and water. In this type of reaction, oxygen is a reactant and typically a hydrocarbon or organic compound is the fuel. Decomposition involves a compound breaking down into simpler substances, synthesis is when two or more substances combine to form a more complex compound, and single replacement is when one element replaces another in a compound. Combustion specifically involves the reaction with oxygen, making it the correct choice in this scenario.

Correct Answer: B

Rationale: The correct answer is B: Single replacement. In this type of reaction, an active metal replaces another metal in an ionic compound, forming a new compound. This is due to the reactivity of the active metal displacing the less reactive metal in the compound. Combustion (choice A) involves a substance reacting with oxygen to produce heat and light. Synthesis (choice C) is the combination of two or more substances to form a new compound. Decomposition (choice D) is when a compound breaks down into simpler substances. In this scenario, single replacement best fits the description of an active metal reacting with an ionic compound to create a new compound.

Correct Answer: A

Rationale: The correct answer is A: Decomposition. This reaction involves breaking down a compound into simpler components through the use of heat, light, or electricity. Decomposition reactions are the opposite of synthesis reactions, where compounds are formed from simpler substances. Combustion involves the reaction of a substance with oxygen to produce heat and light. Single replacement reactions occur when one element replaces another in a compound. In this context, only decomposition aligns with the process of breaking down a compound into its component parts.

Correct Answer: C

Rationale: The correct answer is C: Hydrogen bonding. Hydrogen bonding is the strongest intermolecular force due to the high electronegativity difference between hydrogen and elements like nitrogen, oxygen, or fluorine, leading to a strong partial positive charge on hydrogen. This allows for a strong attraction with the partial negative charge on the electronegative atom of another molecule. Dipole interactions (A) are weaker than hydrogen bonding, dispersion forces (B) are the weakest intermolecular force, and Van der Waals forces (D) are a broad term that encompasses all intermolecular forces, including hydrogen bonding.

Correct Answer: B

Rationale: The mass number represents the total number of protons and neutrons in an atom's nucleus. The atomic number represents the number of protons. By subtracting the atomic number from the mass number, we are left with the number of neutrons. Therefore, the correct answer is B: Number of neutrons. Summary: A: Number of electrons - Incorrect, as the mass number minus the atomic number does not give the number of electrons. C: Number of protons - Incorrect, as the atomic number itself represents the number of protons. D: Number of isotopes - Incorrect, as isotopes refer to atoms of the same element with different numbers of neutrons, not the result of mass number minus atomic number.