The empirical formula of an addition polymer

Question

a) is the same as that of the monomer from which it is formed except that 2 H and 1 O have been added

b) is the same as that of the monomer from which it is formed except that 2 H and 1 O have been subtracted

c) is the same as that of the monomer from which it is formed

d) is the same as that of the monomer from which it is formed except that 2 H and 1 C have been added

e) is the same as that of the monomer from which it is formed except that 2 H and 1 C have been subtracted

Answer 1

Addition polymers, like polyethylene, attack each other without losing small molecules like water.   An H+, say, attacks to open the double bond, which then attacks and opens the next, and the next... the last one in the chain picks up an OH.   So the whole molecule has the same formula as all the monomers together.  The ensemble, the entire chain, has added H2O.   Since an empirical formula is the basic ratio of the elements, that H2O makes no difference since it's one in thousands.  So the answer is C, the empirical formula is unchanged (in spite of the water addition).  

Answer 2

c) is correct...the monomer units simply add to one another to form the polymer.

A general equation is...

n RCH=CH2 ---> R(CH2-CH2)nCH=CH2...the end groups being the last, unreacted monomer unit, theoretically at least. In actuality the polymer can be terminated by traces of impurity in the system, but we cannot count on that happening, and such an addn would be of little significence to the overall high molecular weight.