The ΔH°f of a reaction is recorded at:
Correct answer: C. 298 K
- A. 273 K
- B. 373 K
- C. 298 K
- D. 473 K
Explanation
The standard enthalpy of formation, ΔH°f, is measured under standard conditions, which include a temperature of 25°C (298 K) and a pressure of 1 atm. This standardization allows for consistent comparison of thermodynamic data across different reactions. Option C, 298 K, is the correct answer because it aligns with these standard conditions. Options A (273 K), B (373 K), and D (473 K) are incorrect because they do not represent the standard reference temperature for ΔH°f.
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About Thermochemistry and Energetics of Chemical Reactions
Thermochemistry measures energy changes in chemical reactions and distinguishes exothermic from endothermic processes. Work covers systems, surroundings and state functions, internal energy, the first law of thermodynamics, enthalpy and Hess's law, including the sign conventions used when heat enters or leaves a system.
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