The enthalpy of formation of a compound is:
Correct answer: C. Either positive or negative
- A. Positive
- B. Negative
- C. Either positive or negative
- D. None of the above
Explanation
Enthalpy of formation may be negative or positive. Mg(s) +1/2O2 → MgO(s) ΔHº f = -692kj / mol 1/2 N2(g) O2(g) → No2(g) ΔHº f = 33.18kj / mol
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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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