contestada

7 kg of dimethyl terephthalate is reacted with 5 kg of Ethylene glycol to produce PET. Estimate the amount of polymer that is produced assuming 50% efficiency.

Respuesta :

Explanation:

The given data will be as follows.

         7 kg of dimethyl terephthalate + 5 kg of Ethylene glycol = 12 kg of product

Formula for weight average number is as follows.

                       [tex]w_{n} = \sum w_{i} \times M_{i}[/tex]

                                  = [tex]\frac{7}{12} \times M_{DMT} + \frac{5}{12} \times M_{EG}[/tex]

Molecular weight of DMT = 198.21 g/mol

Molecular weight of ET = 62.07 g/mol

Hence, calculate the weight average number as follows.

          [tex]\frac{7}{12} \times M_{DMT} + \frac{5}{12} \times M_{EG}[/tex]

           = [tex]\frac{7}{12} \times 198.21 g/mol + \frac{5}{12} \times 62.07 g/mol[/tex]          

            = (115.62 + 25.862) g/mol            

             = 141.482 g/mol

Since, efficiency is given as 50% = 0.5

                               0.5 = [tex]\frac{\bar{M_{avg. PET}}}{w_{n}}[/tex]

                [tex]\bar{M_{avg. PET}} = 0.5 \times w_{n}[/tex]

                                  = [tex]0.5 \times 141.482 g/mol[/tex]    

                                  = 70.741 g/mol

As,          [tex]m_{PET} \times \bar{M_{avg. PET}}[/tex] = [tex]m_{DMT} \times M_{DMT} + m_{EG} \times M_{EG}[/tex]

        [tex]m_{PET} \times 70.741 g/mol = 7 \times 198.21 g/mol + 5 \times 62.07 g/mol[/tex]  

                      [tex]m_{PET}[/tex] = [tex]\frac{1697.82}{70.741}[/tex]

                                     = 24 g

Thus, we can conclude that the amount of given polymer is 24 g.