empirical formula (1 Viewer)

[clever angel]

hi

wat's the difference between empirical and moelcular formula

cos i had this question in my trial : wat's da empirical formula for polyethene


thankxxx

 

[LostAuzzie]

An empirical formula shows the relative proportions of elements in a molecule
A molecular formula shows the actual number of elements

For Ethylene:

Molecular Formula:
C2H4
Empirical Formula:
CH2

 

[clever angel]

can u plzz show the working out, cos i have lost my prelim notes

also wats the empirical formula for ethanol?

thankxx

 

[Dreamerish*~]

There isn't much working out involved in converting a molecular formula into an empirical one. If you mean calculating the empirical formula from given percentage compositions of elements in a compound, then look here for examples.

Ethene is C₂H₄, the ratio of C to H is 2:4, which is the same as 1:2, so the empirical formula for ethene is CH₂. It basically shows the ratio of the elements.

Ethanol is C₂H₆O, the ratio of C to H to O is 2:6:1, and can't be further simplified into whole numbers as oxygen is on 1.