Standard enthalpy changes are measure at:
Correct answer: A. 298K
- A. 298K
- B. 273K
- C. 373K
- D. None of the above
Explanation
The standard enthalpy changes are measured under standard conditions, which include a temperature of 298K (25°C). This is the temperature at which most standard thermochemical data is tabulated. Option A correctly identifies this temperature. Option B (273K) is the freezing point of water, and Option C (373K) is its boiling point, neither of which are standard conditions for enthalpy measurements. Option D is incorrect because Option A provides the correct standard temperature.
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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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