A polystyrene having formula Br3C6H3(C3H8)n found to contain 10.46% of bromine by weight. Find the value of n.
(Atomic weight Br=80)
One molecule of polystyrene =3 Bromine atom
10.46% Bromine by weight means =mass of Bromine atomsmass of molecule
10.46100=3×803×80+75+44n
10.46(315+44n)=3×80×100
3294.9+460.24n=3×80×100
460.24n=24000−3294.9
n=44.988
n≅45