Question

De calculat volumul gazului consumat la arderea a 500 g solutie de alcool etilic de 23% ce masa de apa s-a format dupa ardere

Answer 1

Cp=md/ms*100==>md=Cp*ms/100=23*500/100=115g CH3-CH2-OH

n=md/M=115/46=2.5 moli alcool

CH3-CH2-OH + 3O2 --> 2CO2 + 3H2O + Q

1mol C2H6O...3mol O2....2mol CO2...3moli H2O
2.5 mol...x=7.5 mol...y=3.75 mol...z=7.5 moli

n=V/Vmolar==>V=n*Vmolar=3.75*22.4=84L CO2

nH2O=mH2O/M==>mH2O=n*M=7.5*18=135g H2O după ardere

ms=md-mH2O==>mH2O=ms-md=500-115=385g înainte de ardere

mH2O consumat=385-135=250g