Huh I do not understand this
Let us suppose that we have 1 mol of FeCr2O4. I'm going to use approximate masses because I have no idea what your periodic table will say. Just put in the exact masses from your periodic table.
Fe = 56
Cr*2 = 2*52 = 104
O4 = 4*16 = 64
===========
Total = 56 + 104 + 64 = 224
The % oxygen = (64 / 224) * 100 = 28.5 % but none of your answers match this. Perhaps you are talking about Fe2(Cr2O4)3 The brackets make all the difference in the world.
Without going through all the detail I did before, The molecular mass is
Fe * 2 = 112
Cr * 6 = 312
O * 12 = 192
The total molecular mass = 616
The % Oxygen = (192 / 616) * 100 = 31% roughly. That answer isn't there either.
Let's wait and see who else answers.
Answer:

Explanation:
In its raw form, function notation essentially represents an equation with only one unknown variable, expressed in terms of another. Thus, f(x) = x² + 7x can be expressed as
g(x) = 2x + 3
f(g(x)) = (2x + 3)²
f(g(x)) = 4x² + 12x + 9
Hope it helps :) and let me know if you want me to elaborate.
Answer:
plzz mark brainliast:
Explanation:
clue: The reaction has a single reactant.