In those reactions where determination of enthalpy value is difficult by experiments, in such cases enthalpy value can be calculated by:
Correct answer: A. Hess's law
- A. Hess's law
- B. Henry's law
- C. Kirchoff's law
- D. Clapeyron equation '
- E. Boyle's law
Explanation
Hess's Law of Constant Heat Summation (or just Hess's Law) states that regardless of the multiple stages or steps of a reaction, the total enthalpy change for the reaction is the sum of all changes. This law is a manifestation that enthalpy is a state function. It is used to find out the enthalpy of the reaction.
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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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