Calculate the enthalpy change, ΔH, for the process in which 38.9 g of water is converted from liquid at 10.4°C to vapor at 25.0°C . For water, ΔHvap = 44.0 kJ/mol at 25.0°C and Cs = 4.18 J/ (g°C) for H2O(l).
Express your answer to three significant figures and include the appropriate units.
Heat, q, is energy transferred between a system and its surroundings. For a process that involves a temperature change
q = mCsΔT
where Cs is specific heat and mm is mass.
Heat can also be transferred at a constant temperature when there is a change in state. For a process that involves a phase change
q = n ⋅ ΔH
where, n is the number of moles and ΔH is the enthalpy of fusion, vaporization, or sublimation.
The following table provides the specific heat and enthalpy changes for water and ice.
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