Selection of temperature reference for the dissolution process
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Seek guidance on process simulation* Guide 1-14: Producing an HCl aqueous solution at 25°C with a 25% mass percentage of HCl, using gaseous HCl at 100°C and water at 25°C, with a production rate of 1000 kg/h. The specific heat capacities at 100°C for HCl(g), at 25°C for H2O(l), and at 25°C for a 25% HCl solution are 0.815, 4.184, and 2.863 KJ/kg/°C respectively. The enthalpy of solution for the 25% HCl solution is 65.23 KJ per mole of HCl. Determine the heat effect during the production process. I would like to ask the top students: why is 0°C chosen as the reference temperature for this problem?
For aqueous systems, it is best to use the enthalpy value of pure water at 0°C as a reference, since the enthalpy values in existing steam tables take the enthalpy value of pure water at 0°C as zero
Thank you very much for your reply; it was very helpful to me:handshake
Generally, the reference temperature for systems involving chemical reactions is set at 25°C, as most of the relevant thermodynamic parameters are those at 25°C, which facilitates calculations and reduces the amount of work required； For systems other than chemical reactions, 0°C is generally adopted for convenience in calculations; however, the calculation results are independent of the choice of the reference temperature.