Question

Intr-o solutie cu volumul de 500ml se gasesc dizolvate 9 g de acid oxalic. Ce concentratie normala are solutia ? (AH=1, AC=12, AO=16)

Answer 1

md=9g C2H2O4
Vs=500mL=0.5L


MHOOC-COOH==>C2H2O4=2AC+2AH+4AO=2*12+2+64=90g/mol
sau 

MHOOC-COOH*2H2O [acidul oxalic prin alte carti este luat anhidru sau cu 2 molecule de apa..] = 90 + 36= 126g/mol

Eg=M/2=126/2=63g
sau
Eg=M/2=90/2=45g

Cn=md/Eg*Vs=9/63*0.5=9/31.5=0.285 Eg/L

sau

Cn=md/Eg*Vs=9/45*0.5=9/22.5=0.4 Eg/L