One liter of liquid water at 20ºC and atmospheric pressure is contained in an in

Question

One liter of liquid water at 20ºC and atmospheric pressure is contained in an insulated vessel. We then drop a piece of hot metal at 175ºC (weighing 25 g) into the water. The specific enthalpy of the metal piece is given by H =17.28T , where temperature is in ºC and the specific enthalpy is in J/g. What reference state was used as basis for the specific enthalpy formula? Assume an adiabatic process, negligible heat transfer to the walls of the vessel, and negligible evaporation of water during the process. With these assumptions, what is the final temperature of the vessel’s content?

Explanation / Answer

Enthalpy H =E + PV, E = Internal energy , P = Pressure , V= Volume

Specific enthalpy = Enthalpy / Mass = E + PV

As per First law of thermodynamics E2 - E1 =Q -W , Q = Heat transfer , W = Work

For constant pressure W= P (V2 -V1)

Substitue E2-E1= Q - P (V2- V1)

Heat transfer at constant pressure Q = CP (T2 -T1)

FOR ENTHALPY = (H2-H1) = CP (T2- T1)

Please substitute above values in question in formula for results

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