Question

urgent
prin oxidarea unui amestec echimolecular de etanol si 1,3-propandiol se folosesc 800mL solutie K2Cr2O7 0,3M.Determina masa amestecului initial de alcooli.

Answer 1

Amestec echimolecular: x moli etanol si x moli diol
1mol.................2moli
CH3-CH2-OH + 2[O] -> CH3-CH=O + H2O
x moli...............2x moli
1mol................................4moli
HO-CH2-CH2-CH2-OH + 4[O] -> O=HC-CH2-CH=O + 2H2O
x moli..............................4x moli
1mol..............................3moli
K2Cr2O7 + 4H2SO4 -> 3[O] + K2SO4 + Cr2(SO4)3 + 4H2O
2x................................6x moli
n=Cm*Vs=0,3*0,8=0,24moli
2x=0,24 => x=0,12moli
n=m/M => m=n*M
MC2H6O=46g/mol
MC3H8O2=76g/mol
mamestec=122x=122*0,12=14,64g