They all can condense and manipulate light<span />
I'm assuming that by "miles" you mean moles.
If O2 is the excess reactant, that means Fe is the limiting reactant. That means that the amount of product being formed depends on the amount of Fe reactant present. To calculate the moles of Fe2O3 formed, start with the given 6.4 moles of Fe and use the mole to mole ratio given by the reaction as shown below:
6.4 mol Fe x

=
3.2 mol Fe2O3
Explanation:
A synthesis reaction: It is defined as a kind of reaction where one and more than one reactant attached and creates an individual product.
The formation of the water is an example of a synthesis reaction because here more than one reactants combine and create a single product (water). Water formation occurs when 2 hydrogens and an oxygen share electrons through covalent bonds.
2H + O ----> H2O.
B. Most rocks are composed of single mineral