The amount of heat absorbed by one mole of solid at 1 atm when it melts into liquid form is denoted by _ .
Correct answer: B. ΔHf
- A. ΔHv
- B. ΔHf
- C. ΔHi
- D. ΔHs
Explanation
The molar heat of fusion (ΔHfus) of a substance is the heat absorbed by one mole of that substance as it is converted from a solid to a liquid. Since the melting of any substance absorbs heat, it follows that the freezing of any substance releases heat.
This question appeared on the UHS MDCAT 2008 paper, which you can sit online with every answer explained.
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About Enthalpy
Enthalpy is the heat content of a system measured at constant pressure, and its change indicates whether a reaction or physical process is endothermic or exothermic. The topic covers state functions, enthalpy diagrams, standard enthalpy of formation, combustion and neutralisation, and the relationship between ΔH and internal energy change.
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