____ Fe + 3 O2→→ 2 Fe2O3How many atoms of iron must react with 3 molecules of oxygen to form 2 molecules of iron oxide?

To determine the number of atoms of iron that must react with 3 molecules of oxygen to form 2 molecules of iron oxide, we need to use the coefficients in the balanced chemical equation.

The balanced equation is: 4 Fe + 3 O2 → 2 Fe2O3

From the equation, we can see that 4 atoms of iron react with 3 molecules of oxygen to form 2 molecules of iron oxide.

To find the number of atoms of iron needed, we can set up a proportion:

4 atoms of iron / 4 Fe = 2 molecules of iron oxide / 2 Fe2O3

Simplifying the proportion, we get:

1 atom of iron = 1 molecule of iron oxide

Therefore, to form 2 molecules of iron oxide, we need 2 atoms of iron to react with 3 molecules of oxygen.