Question

99 PCT!Aflati masa de fier din 500g amestec FeO si Fe2O3, in care cele doua substante se afla in raport masic FeO:Fe2O3=2:3

Answer 1

Masa amestec = masa FeO + masa Fe2O3
Notam cu x - masa FeO si y - masa Fe2O3
x/y = 2/3 => 2y=3x => y = 3x/2
Stim: x+y = 500
=> x + 3x/2 = 500 => 2x + 3x = 1000 => x =  200 g FeO
y = 3x/2 = 3*200/2 = 300 g Fe2O3
70 g FeO........56 g Fe
200 g FeO...........a g Fe
a = 160 g Fe
160 g Fe2O3..........2*56 g Fe
300 g Fe2O3............b g Fe
b = 210 g Fe
masa Fe = a + b = 160+210 = 370 g Fe