g NH4NO3 MgSO4 [1] Mass of salt (g) 2.005 1.993 [2] Volume of DI water (mL) 49.8 50.0 Mass of DI water (g) 49.8 check_circle 49.8 check_circle [3] Temperature of DI water (°C) 23.4 23.5 [4] Temperature of mixture after dissolution (°C) 20.4 30.9 Temperature difference (°C) -3 check_circle 7.4 check_circle [5] Total mass in reaction (g) 51.805 check_circle 51.993 check_circle Total moles reacted (mol) .025 highlight_off .017 highlight_off Total heat of the reaction (cal) 155.4 highlight_off 384.7 highlight_off [6] Enthalpy of solution ΔHsolution (cal/mol) -6216.6 highlight_off 23177.6 highlight_off

3. consider a process in which a gas with the properties of air expands at constant pressure as described by the cups of air discussion in class. one kilogram of air starts out at 1 atm and 290 k. the air expands its volume by absorbing a sufficient amount of thermal energy to increase the temperature at constant pressure to 350 k. a. on a p-v diagram, sketch this process with point a as the starting point and point b as the ending point. b. if the process is completely reversible, calculate the thermal energy added from an external source. c. calculate the entropy change for this process assuming it is reversible. d. calculate the work delivered externally if this is a reversible process. e. if the process is completely irreversible, calculate the amount of entropy change for the process that is due to irreversibilities. f. if the process is completely irreversible, calculate the amount of thermal energy added from an external source and compare this result to the thermal energy calculated in part b. g. for the completely irreversible process, calculate the entropy change due to this thermal energy addition. h. for the completely irreversible process, calculate the total entropy change and compare it to the entropy change in part c.