<u>Answer:</u> The given amount of iron reacts with 9.0 moles of
and produce 6.0 moles of 
<u>Explanation:</u>
We are given:
Moles of iron = 12.0 moles
The chemical equation for the rusting of iron follows:

By Stoichiometry of the reaction:
4 moles of iron reacts with 3 moles of oxygen gas
So, 12.0 moles of iron will react with =
of oxygen gas
- <u>For iron (III) oxide:</u>
By Stoichiometry of the reaction:
4 moles of iron produces 2 moles of iron (III) oxide
So, 12.0 moles of iron will produce =
of iron (III) oxide
Hence, the given amount of iron reacts with 9.0 moles of
and produce 6.0 moles of 
Answer:
c. Cr
Explanation:

The compound is containing
ion.
If acid reacts with it, CO_2 evolves.

therefore, Cr would form a precipitate when added to an aqueous solution of this compound. Cr2CO3 is the precipitate.
Answer:
Atom: The smallest particle of an element that has the properties of the element and can exist either alone or in combination.
Particle: One of the very small parts of matter (as a molecule, atom, or electron)
Kinetic: Of or relating to the motions of material bodies and the forces and energy associated with them
Explanation: