Question

Un amestesc de propena si 2-butena in raport molar 1:2 este oxidat cu permanganat de potasiu in acid sulfuric. Substanta organica formata se dizolva in 470 g apa formand o solutie de concentratie=6%. Ce masa de propena se gaseste in amestesc?

Answer 1

CH2=CH-CH3 + 5 [O] => CO2 + CH3-COOH + H2O
CH3-CH=CH-CH3 + 4 [O] => 2 CH3-COOH
c = md/ms * 100
ms = md + m apa
6 = md/(470+md) * 100
100md = 2820 + 6md => md = 30 g acid acetic
1 mol propena...........60 g acid acetic
a moli propena...............x g acid
60a = x
1 mol 2-butena...............2*60 g acid acetic
b moli 2 butena..................y g acid
y = 120b
x+y = 30 => 60a + 120b = 30 => 2a + 4b = 1
a/b = 1/2 => b = 2a
2a + 4*2a = 1 => 10a = 1 => a = 0.1 moli propena
b = 2a = 2*0.1 = 0.2 moli butena
m propena = 0.1 * 42 = 4.2 g