Question

Prin analiza functionala a12,3 grame dintr-o substanta oraganica s-au obtinut 2,7 grame de H2O, 4,48 L Co2 si 8 grame de Br2.Stiind ca densitatea in raport cu hidrogenul este 123sa se determine formula bruta si formula moleculara

Answer 1

-din densitate, calculez masa molara a compusului
d=miu/miu,H2
123= miu/2----> miu= 246g/mol
-in 12,3g compus.....2,7gH2O.....4,48LCO2.......8gBr2
    246g..................m= 54g............v= 89,6l.........160g
-deduc moli H,C,Br
niu= m/miu;  niu= 54g/18g/mol= 3molH2o------------------> 6molH
niu=v/22,4;   niu= 89,6l/22,4l/mol= 4molCO2--------------> 4molC
niu=m/miu;   niu= 160g/160g/mol=1molBr2--------------------.> 2molB2
compusul are formula bruta (C4H6Br2)n
(48+6+160)g=214g;  diferenta (246-214)g=32g  corespunde la 2O
DECI FORMULA MOLECULARA ESTE:  C4H6O2Br2