Question

In conditii normale 1 dm3 intr-o hidrocarbura gazoasa cantareste 2.5g. In urma arderii a 0.2 moli din aceeasi hidrocarbura se degaja 35.2g CO. Determina formula moleculara a hidrocarburii.

Answer 1

1dm³............2,5g
22,4dm³.............M g
M=56g/mol
notam din nou hidrocarbura: CxH2y
1mol.................................44x
CxH2y + (2x+y)/2 O2 -> xCO2 + yH2O
0,2moli...........................35,2g
44x=35,2/0,2=176 => x=4
Mhidrocarbura=12x+2y=56
=> 48 + 2y = 56 => 2y=8 => y=4
formula moleculara: C4H8