Mark the incorrect statement about enthalpy changes (∆H°):
Correct answer: C. ΔH°at - The enthalpy change when one mole of gaseous atoms is formed from its compound under standard conditions
- A. ΔH°sol - The enthalpy change is the amount of heat absorbed or evolved when one mole of a substance is dissolved in excess solvent
- B. ΔH comb- The enthalpy change when one mole of a substance is burnt in excess air
- C. ΔH°at - The enthalpy change when one mole of gaseous atoms is formed from its compound under standard conditions
- D. ΔH°n - The enthalpy change when one mole of water is formed by the reaction of one mole of H⁺ ions from an acid with one mole of OH⁻ ions from a base
Explanation
The "enthalpy of atomization" is a thermodynamic quantity that represents the energy change associated with the process of breaking a chemical compound into its individual atoms in the gaseous state and is commonly expressed in units of energy per mole, such as kilojoules per mole (kJ/mol) or kilocalories per mole (kcal/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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