To calculate the enthalpy change for the overall reaction, we need to first determine the number of moles of the monomer that is polymerized. Then, we can use the heat of reaction to find the enthalpy change.1. Calculate the number of moles of monomer:We are given the mass of the monomer 5.0 g but not its molar mass. To proceed, we will assume the molar mass of the monomer is M g/mol.moles of monomer = mass of monomer / molar mass of monomermoles of monomer = 5.0 g / M g/mol2. Calculate the enthalpy change for the overall reaction:We are given the heat of reaction -150 kJ/mol and the change in moles of gas n = +2 moles gas/mol .Enthalpy change H = heat of reaction moles of monomerH = -150 kJ/mol 5.0 g / M g/mol H = -750 kJ / MWithout the molar mass of the monomer, we cannot provide a specific value for the enthalpy change. However, the enthalpy change for the overall reaction can be expressed as -750 kJ / M, where M is the molar mass of the monomer in g/mol.