X: a mol N2, b mol H2
mX = mY = 28a + 2b = 2*3,889( a + b)
=> b = 3,5a => chọn a = 1 => b = 3,5 => mol X = 4,5 => mX = mY = 35
MY = 2*4,581 => mol Y = 35/9,162 = 3,82
N2 + 3 H2 -> 2 NH3
x---------3x--------2x
=> mol Y = (1-x)+(3,5-3x)+2x = 4,5 - 2x = 3,82 => x = 0,34
H = 100x/1 = 34%