Calculate the enthalpy change of the polymerization of styrene using the following information: Reactants: - Styrene: C8H8 (l) - Peroxide initiator: C6H5OOC(CH3)3 (l) Products: - Polystyrene: (C8H8)n (s)- Byproduct: CO2 (g)Given information: - Heat of formation of CO2 (g) = -393.5 kJ/mol - Mass of styrene used = 50 g - Molarity of the initiator solution = 0.3 M - Volume of the initiator solution used = 25 mL - Density of the initiator solution = 0.89 g/mL - The reaction is carried out at a constant pressure of 1 atm and a temperature of 25°C.

Question

Calculate the enthalpy change of the polymerization of styrene using the following information: Reactants: - Styrene: C8H8 (l) - Peroxide initiator: C6H5OOC(CH3)3 (l) Products: - Polystyrene: (C8H8)n (s)- Byproduct: CO2 (g)Given information: - Heat of formation of CO2 (g) = -393.5 kJ/mol - Mass of styrene used = 50 g - Molarity of the initiator solution = 0.3 M - Volum

Answer 1

To calculate the enthalpy change of the polymerization of styrene, we need to find the moles of styrene and the moles of CO2 produced. Then, we can use the heat of formation of CO2 to find the enthalpy change.1. Calculate the moles of styrene used:Molecular weight of styrene  C8H8  =  8 * 12.01  +  8 * 1.01  = 104.15 g/molMoles of styrene = mass of styrene / molecular weight of styreneMoles of styrene = 50 g / 104.15 g/mol = 0.480 mol2. Calculate the moles of initiator used:Moles of initiator = Molarity * VolumeMoles of initiator = 0.3 M * 0.025 L = 0.0075 mol3. Assume that the reaction goes to completion and all the styrene is converted to polystyrene and CO2. Since the initiator is used to start the reaction, it does not affect the stoichiometry of the reaction. Therefore, the moles of CO2 produced will be equal to the moles of styrene used.Moles of CO2 produced = 0.480 mol4. Calculate the enthalpy change using the heat of formation of CO2:Enthalpy change = moles of CO2 * heat of formation of CO2Enthalpy change = 0.480 mol *  -393.5 kJ/mol  = -188.88 kJThe enthalpy change of the polymerization of styrene is -188.88 kJ.