Water vapor standard enthalpy

Calculate the heat of vaporization, A.H°ap, of water, using standard enthalpies of formation (Table 6.2). 

Self-Test 8.2A The vapor pressure of water at 25°C is 23.76 Torr and its standard enthalpy of vaporization at that temperature is 44.0 kj-mol-1. Estimate the vapor pressure of water at 35°C. 

The standard molar enthalpy of formation, A// , is the amount of heat absorbed when 1 mole of the substance is produced from its elements in their standard states. At 25°C, A// of liquid water is -285.8 kJ/mol and A// of water vapor is -241.8 kJ/mol. This means that more heat is released when liquid water is formed from its elements, then when gaseous water is formed from its elements. So, the formation reaction of liquid water is... 

Table 6.3 Experimental Standard Enthalpies of Vaporization (AvapH,) and Standard Enthalpies of Transfer from Water to Air (Aaw//,) of Selected Organic Compounds at 25 °C ... 

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