calculate standard enthalpy of formation of carbon disulphide given that the standard enthalpy of combustion of C,S and - Chemistry - Thermodynamics

Question

calculate standard enthalpy of formation of carbon disulphide given
that the standard enthalpy of combustion of C,S and CS2 are -393 3
, -293 72 , -1108 76 KJ mol respectively

Geetha · Accepted Answer

CS2 + 3O2 → CO2 + 2 SO2   ∆H= - 1108
76 kJ mol-1C + O2 → CO2          ∆H= - 393
3 kJ mol-1S +O2 → SO2          ∆H= - 293
72 kJ mol-1∆H= HP - HR     = ∆HCO20 + ∆HSO20 - ∆HCS20 + 3 ∆HO20- 1108
76 = - 393 3 + (- 293
72) - ∆HCS20    (since enthalpy of formation of oxygen = 0)∆HCS20  = - 393
3 + (- 293 72) + 1108
76     = 421 74 kJ/mol

calculate standard enthalpy of formation of carbon disulphide . given that the standard enthalpy of combustion of C,S and CS2 are -393.3 , -293.72 , -1108.76 KJ mol respectively