To calculate the enthalpy of polymerization of polystyrene, we need to determine the amount of heat released per mole of styrene monomer. First, we need to find the number of moles of styrene monomer in 25 grams.The molecular weight of styrene C8H8 is: 8 x 12.01 g/mol for C + 8 x 1.01 g/mol for H = 104.15 g/molNow, we can find the number of moles of styrene monomer in 25 grams:moles = mass / molecular weightmoles = 25 g / 104.15 g/mol = 0.240 molSince 100 kJ of heat energy is released during the polymerization of 0.240 mol of styrene monomer, we can calculate the enthalpy of polymerization per mole:enthalpy of polymerization = heat energy released / moles of styrene monomerenthalpy of polymerization = 100 kJ / 0.240 mol = 416.67 kJ/molTherefore, the enthalpy of polymerization of polystyrene is approximately 416.67 kJ/mol.