Question

Se ard 1.44 g de substanta organica cu densitatea vaporilor fata de aer egala cu 2.49.
Stiind ca se obtin 1.792 dm3 CO2 so 1.44 g de H2O se cere:
formula procentuala, bruta si moleculara

Answer 1

1mol CO2........22,4L........12gC
.......................1,792L..........xgC
x=1,792*12/22,4=0,96g C
1mol H2O......18g.........2gH
....................1,44g.........ygH
y=1,44*2/18=0,16g H
melemente=1,12g => compusul contine si oxigen
mO=0,32g
.............................. :0,02
C: 0,96/12=0,08. 4
H: 0,16/1=0,16. 8
O: 0,32/16=0,02. 1
(C4H8O)n
daer=Msubst/Maer => Msubst=2,49*28,9=72g/mol
M(C4H8O)n=72n=72 => n=1
formula moleculara: C4H8O
formula bruta: C:H:O=4:8:1
72g.........100%
48g......66,66% C
8g.......11,11% H
16g.....22,22% O