IGCSE/GCSE/O & A Level/IB/University Student Forum

Qualification => Subject Doubts => IGCSE/ GCSE => Sciences => Topic started by: Wahab09 on June 11, 2009, 05:45:44 pm

Title: URGENT CHEM PP1 QUES!
Post by: Wahab09 on June 11, 2009, 05:45:44 pm
If ethene polymerises to polyethene.. what remains the same?

thanks and can u explain y please?
Title: Re: URGENT CHEM PP1 QUES!
Post by: .... on June 11, 2009, 05:46:53 pm
Quote from: Wahab09 on June 11, 2009, 05:45:44 pm
If ethene polymerises to polyethene.. what remains the same?

thanks and can u explain y please?
empirical formula.
empirical formula of ethene is C2H4
Since polyethene is just ethene molecules repeating, the empirical formula is the same.
Title: Re: URGENT CHEM PP1 QUES!
Post by: Ghost Of Highbury on June 11, 2009, 05:47:47 pm
the empirical formula is the same

but the structural formula is different
Title: Re: URGENT CHEM PP1 QUES!
Post by: Wahab09 on June 11, 2009, 05:48:19 pm
but the molecular formula is still C2H4 it didnt change also?
Title: Re: URGENT CHEM PP1 QUES!
Post by: .... on June 11, 2009, 05:50:33 pm
Quote from: Wahab09 on June 11, 2009, 05:48:19 pm
but the molecular formula is still C2H4 it didnt change also?
It is just like, if you join four molecules of ethene to form polyethene, the molecular formula is like C8H16, but empirical formula isn't C8H16
Title: Re: URGENT CHEM PP1 QUES!
Post by: nid404 on June 11, 2009, 05:51:30 pm
Quote from: Wahab09 on June 11, 2009, 05:48:19 pm
but the molecular formula is still C2H4 it didnt change also?

molecular formula is the total number of different atoms in a molecule. in a polymer we don't know how many ethene molecules have joined...r u getting that. The molecular formula changes....very much
Title: Re: URGENT CHEM PP1 QUES!
Post by: astarmathsandphysics on June 11, 2009, 05:52:45 pm
The empirical forumular is reduced to the flowest terms like


-CH2- or CH2
Title: Re: URGENT CHEM PP1 QUES!
Post by: Wahab09 on June 11, 2009, 05:56:38 pm
got it.. thanks guys ;D