M metiletanamină (C3H9N) = 59 g/mol
M dimetiletanamină (C4H11N) = 73 g/mol
m amestec = x*59 + y*73
1 mol metiletanamină..................1*6,022*10^23
x....................................................a
a = 6,022*10^23x
1 mol dimetiletanamină....................2*6,022*10^23
y............................................................b
b = 2*6,022*10^23y
a+b = 72,264*10^23
6,022*10^23x + 2*6,022*10^23y = 72,264*10^23
x+2y = 12 => x = 12-2y
59x + 73y = 528
59(12-2y) + 73y = 528
708 - 118y + 73y = 528
y = 4 moli B
x = 12-2*4 = 4 moli A
x/y = 4/4 = 1/1 - adevărat
