I still need help with this one, the last one I tried was incorrect. Thanks! Bas
ID: 492826 • Letter: I
Question
I still need help with this one, the last one I tried was incorrect. Thanks!
Based on the thermodynamic properties provided for methanol (below and to the right), determine from the following list the equation(s) necessary to calculate the amount of energy needed for 22.8 kg of methanol from all gas at 65 degree C to -112 degree C.? q = n(37 kJ/mol) q= n(- 37 kJ/mol) q = n(48.7 J/mol middot degree C) Delta T, where Delta T is positive q = n(43.8 J/mol middot degree C) Delta T. where Delta T is negative q = n (-3. 18 kJ/mol) q = n (3.18 kJ/mol) q = n(81.1 kJ/mol middot degree C) Delta T. where Delta T is negative 8 kJ/mol) q = n(48.7 J/mol middot degree C) Delta T, where Delta T is negative q = n (43.8 J/mol middot degree C) Delta T. where Delta T is positive) q = n (81.1 J/mol degree C) Delta T. where Delta T is positive) Is this overall process endothermic or exothermic? endothermic exothermic Cannot be determined from the given informationExplanation / Answer
For conversion of methanol gas at 65 oC to -112.oC
the equations would be as follows,
step 1 : gas at 65 oC to liquid at 65 oC
q = n(-37 kJ/mol)
step 2 : liquid at 65 oC to liquid at -94 oC
q = n(81.1 J/mol.oC), where dT is negative
step 3 : liquid at -94 oC to solid at -94 oC
q = n(-3.18 kJ/mol)
step 4 : solid at -94 oC to solid at -112 oC
q = n(48.7 J/mol.oC), where dT is negative
Therefore, the overall process would thus be,
exothermic
Heat is given off to cool the entire system.