Etena e de puritate 80% => aducem la 80%
p/100=mpura/mimpura => 80/100=mpura/3,2 => mpura=2,56kg etena
28n kg...............28n kg
nCH2=CH2 -> (-CH2-CH2-)n
2,56kg...............a=2,56kg
randamentul e de 75% => calculam cantitatea trebuie adusa la 75%
75/100=mpractica/2,56 => mpractica=2,56*75/100=1,92kg polietena