I have a problem with solving this type of chemistry problem. Please Help!

Which is true of the reactants in this displacement reaction? fe + 2hcl fecl2 + h2 a. the reactants are located to the left of the arrow in the chemical equation. b. the reactants contain 1 iron atom, 2 hydrogen atoms, and 1 chlorine atom. c. the reactants are the atoms, molecules, or compounds formed in the reaction. d. the reactants have the same physical and chemical properties as the products.

Iknow the answer to 13 is b and 14 is d. i just need to know why the correct answers are correct

Asample of aluminum foil contains 8.60 × 1023 atoms. what is the mass of the foil?