What is the percent by mass of sodium in Na2SO4? total mass of element in compound molar mass of compound Use %Element x 100
Answer: The given statement is true.
Explanation: If this reaction would have occurred, then this reaction would be considered as displacement reaction.
Displacement reactions are the reaction in which more reactive element displaces the less reactive element in a chemical reaction. This is based on the reactivity of elements.
Reactivity of elements is the tendency of the elements to gain or loose electrons. The reactivity decreases down the group in a periodic table.
In the given reaction, Iodine and chlorine are the elements of the same group in the periodic table and iodine lies below chlorine in the group. So, the reactivity of iodine is less than the reactivity of chlorine.
Hence, in the given reaction, iodine will not replace chlorine because it lies below in the periodic table.

The given question is incomplete. The complete question is:
The combustion of propane (C3H8) in the presence of excess oxygen yields
and
When only 2.5 mol of
are consumed in order to complete the reaction, ________ mol of
are produced.
Answer: Thus when 2.5 mol of
are consumed in their reaction, 1.5 mol of
are produced
Explanation:
The balanced chemical equation is:

According to stoichiometry :
5 moles of
produce = 3 moles of 
Thus 2.5 moles of
will produce =
moles of 
Thus when 2.5 mol of
are consumed in their reaction, 1.5 mol of
are produced
Fe O
2 3 is what i would put