Calculate the enthalpy of polymerization of ethylene from the following data: Ethylene, C2H4(g) polymerizes to form polyethylene, (C2H4)n(s) with ΔHrxn = -44.0 kJ/mol at 298 K. Additionally, it is known that the standard enthalpies of formation of C2H4(g) and polyethylene (C2H4)n(s) are 52.3 kJ/mol and -128.2 kJ/mol, respectively. Assuming the enthalpy of polymerization is independent of temperature, calculate ΔHºp for the reaction.

Question

Calculate the enthalpy of polymerization of ethylene from the following data: Ethylene, C2H4(g) polymerizes to form polyethylene, (C2H4)n(s) with ΔHrxn = -44.0 kJ/mol at 298 K. Additionally, it is known that the standard enthalpies of formation of C2H4(g) and polyethylene (C2H4)n(s) are 52.3 kJ/mol and -128.2 kJ/mol, respectively. Assuming the enthalpy of polymerization is independent of temperature, calculate

Answer 1

To calculate the enthalpy of polymerization  Hp  for the reaction, we can use the following equation:Hp = Hf products  - Hf reactants In this case, the reactants are ethylene  C2H4 g   and the products are polyethylene   C2H4 n s  . We are given the standard enthalpies of formation  Hf  for both substances:Hf C2H4 g   = 52.3 kJ/molHf  C2H4 n s   = -128.2 kJ/molNow, we can plug these values into the equation:Hp =  -128.2 kJ/mol  -  52.3 kJ/mol Hp = -180.5 kJ/molTherefore, the enthalpy of polymerization for the reaction is -180.5 kJ/mol.