The table below shows how much water was absorbed by three materials used to make plant pots for seedlings. Fig. 1 shows the test: each dry pot is placed in...

The table below shows how much water was absorbed by three materials used to make plant pots for seedlings. Fig. 1 shows the test: each dry pot is placed in water for 24 hours, then its mass is measured again. One pot is made from a starch-based polymer, one from polyethylene and one from fired clay. The nursery needs a pot that can be planted directly into damp soil and then break down after the seedling has grown.

(a) Use Table 1 to state which material absorbed the least water. [1]
(b) What type of polymer is the starch-based material likely to be: naturally occurring or synthetic? [1]
(c) Explain why the starch-based polymer may be a better choice than polyethylene for this use. [2]

A museum conservator finds a 1970s raincoat that has become brittle. Fig. 1 is a simplified structural diagram of part of its poly(chloroethene) coating. The carbon atoms form the main chain and each chlorine atom is attached to a carbon atom. The conservator wants to explain why this material is not made from separate small molecules like sodium chloride. The coat had been stored beside a radiator for many years, so the coating has lost some flexibility.

(a) Name the element, other than carbon and hydrogen, shown in Fig. 1. [1]
(b) Complete this sentence: poly(chloroethene) is made by joining many small molecules called ________. [1]
(c) Explain why heating near the radiator could make the coating less suitable for a raincoat. [2]