Answers to questions on Environmental impact - plastics

1. The substance can be identified as PETE as it is the only one of the three that contains a C=O functional group responsible for the absorption at 1720 cm^-1 in the infrared spectrum. This gives it a RIC of 1.

2. (a) C_8nH_8n(s) + 10nO₂(g) → 8nCO₂(g) + 4nH₂O(g)

If the two hydrogen atoms at either end of the polymer are included then the equation becomes:

C_8nH_8n+2(s) + (10n + 0.5)O₂(g) → 8nCO₂(g) + (4n+1)H₂O(g)

(b) It is a very unsaturated compound so at lower temperatures it will give a choking smoky flame full of particles of carbon. It may also form harmful dioxins which are carcinogenic and cause birth defects.

3. Phthalate esters are thought to be hazardous to health. One of the ways in which they are absorbed by humans is by breathing them in. Low molecular mass phthalate esters are much more volatile and so give a higher concentration in the atmosphere and are absorbed more readily than less volatile higher molecular mass phthalate esters.

4. (a) Polychlorinated biphenyls (PCBs).

(b) Old electrical transformers or capacitors.

(c) They are carcinogenic.

Answers to Environmental impact - plastics questions