Employing the bond enthalpy values listed in Table 8.4, estimate the molar enthalpy change occurring upon (a) polymerization of ethylene. (b) formation of nylon 6,6. (c) formation of polyethylene terephthalate (PET).

Verified step by step guidance

1. Identify the chemical reaction involved in the formation of polyethylene terephthalate (PET). PET is typically formed through a condensation reaction between terephthalic acid and ethylene glycol.
2. Write the balanced chemical equation for the formation of PET. This will help in identifying the bonds broken and formed during the reaction.
3. List the bond enthalpy values for all the bonds involved in the reactants and products. You will need the bond enthalpies for C-H, C-C, C=O, O-H, and C-O bonds.
4. Calculate the total energy required to break all the bonds in the reactants. This involves multiplying the bond enthalpy of each bond by the number of such bonds in the reactants and summing them up.
5. Calculate the total energy released in forming all the bonds in the products. Again, multiply the bond enthalpy of each bond by the number of such bonds in the products and sum them up.

Key Concepts

Bond Enthalpy

Bond enthalpy, or bond dissociation energy, is the amount of energy required to break one mole of a specific type of bond in a gaseous molecule. It is a crucial concept in thermochemistry as it helps predict the energy changes during chemical reactions. Higher bond enthalpy values indicate stronger bonds, which require more energy to break, influencing the overall enthalpy change of a reaction.

Molar Enthalpy Change

Molar enthalpy change refers to the change in enthalpy per mole of a substance during a chemical reaction. It is calculated by considering the bond enthalpies of the reactants and products involved. This concept is essential for estimating the energy absorbed or released during the formation or breaking of chemical bonds, allowing for the prediction of reaction feasibility and stability.

Polyethylene Terephthalate (PET) Formation

Polyethylene terephthalate (PET) is a polymer formed through the condensation reaction of terephthalic acid and ethylene glycol. Understanding the formation of PET involves recognizing the types of bonds formed and broken during the reaction. The enthalpy change associated with this process can be estimated using bond enthalpy values, which helps in assessing the energy efficiency and stability of the polymerization reaction.