Question

9,8 g amestec echimolecular de propena si 1-butena see barboteaza intr-o sol. acidulata de K2Cr2O7.Referitor la asta care sunt corecte ?
a.amestecul de alchene decoloreaza 3,33 l sol.acidulata de K2Cr2O7 de concentratie 0,1 molar
b.se degaja 4,48 l CO2 (c.n.)
c. amestecul final se gasesc 2 acizi carboxilici in rap. molar 1:1
d.in amestecul initial se gasesc0,2 moli alchene

Answer 1

Mpropena=42g/mol; Mbutena=56g/mol
mamestec=42x+56x=98x=9,8 => x=0,1moli alchena
=> 0,2moli alchene, caci avem Amestec echimolecular
1mol..................5moli...22,4l..............1mol
CH2=CH-CH3 + 5[O] -> CO2 + H2O + CH3-COOH
0,1moli....................0,5moli..2,24l.............0,1moli
1mol..........................5moli..22,4l.............1mol
CH2=CH-CH2-CH3 + 5[O] -> CO2 + H2O + CH3-CH2-COOH
0,1moli....................0,5moli..2,24l.............0,1moli
1mol.............................3moli
K2Cr2O7 + 4H2SO4 -> 3[O] + K2SO4 + Cr2(SO4)3 + 4H2O
0,33moli......................1mol
Vs=n/Cm=0,3333/0,1=3,333l K2Cr2O7
VCO2=2,24+2,24=4,48l CO2
acid acetic:acid propionic=0,1:0,1=1:1
corecte sunt toate 4