The enthalpy of formation of ionic compounds is
Correct answer: C. Always greater than lattice energy
- A. Always less than lattice energy
- B. Same as lattice energy
- C. Always greater than lattice energy
- D. May or may not be same as lattice energy
Explanation
Enthalpy of formation (ΔHf) includes lattice energy (LE) plus the additional enthalpy changes needed to form ions from their elements (such as atomization and ionization). So, ΔHf = LE + other positive steps, making the overall enthalpy of formation numerically greater than lattice energy alone.
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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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