A) 10.0g of Iron is

of Iron.
One mole of dihydrogen is required to form one mole of iron, hence you'll need

of dihydrogen.
B) Likewise : 2.50g of Iron is

of Iron, hence we'll need

of Fe2O3.
Compounds are different from elements primarily because compounds are composed of one or two elements. In this case, when elements are combined to form a compound,the reaction incurs a chemical change which results to a product with different properties as its base elements.
Answer:
Argon has three electron shells. The third shell is filled with eight electrons. That is why it does not easily combine with other elements.
Explanation:
Answer:- D. 1.8 moles of Fe and
.
Solution:- The balanced equation is:

let's first figure out the limiting reactant using the given moles and mol ratio:

= 5.4 mol CO
From calculations, 5.4 moles of CO are required to react completely with 1.8 moles of Iron(III)oxide but only 2.7 moles of CO are available. It means CO is limiting reactant.
Products moles depends on limiting reactant. Let's calculate the moles of each reactant formed for given 2.7 moles of CO.

= 1.8 mol Fe

= 
So, the correct choice is D. 1.8 moles of Fe and
are formed.