NOTEZ substanta CaHbOc
-calculez M din densitate
d= M / M,aer--> 3,114= M/29--> M= 90g/mol
-calculez moli ce intra in reactie:
niu= 9g/90g/mol= 0,1mol
-ecuatia reactiei
CaHbOc ardere----> aCO2 + b/2H2o
0,1mol 0,1a...mol.......0,1b/2 mol
9g 17,6.g................9g
0,1ax44=17,6--->a= 4molC
0,1b/2x18= 9----y= 10 molH
-deduc moliO
90 -4X12-10=32--. >32gO
niu= 32g/16g/mol=2molO
substanta este C4H10O2