Answer:
That's pretty easy,if you have a grasp of Elements, Compounds and their Symbols ans Molecular formula.
So, Let's get started!
Our reactions are as follows:
- Sodium(Na) + Chlorine(Cl) ---> Sodium chloride(NaCl)
Think of a compound that has both Sodium and Chlorine and is very common.
Common salt — Sodium chloride!
Yeah, that's it! It has both Sodium and Chlorine in it's molecular formula. (NaCl)
- Magnesium(Mg) + Oxygen(O2) ---> Magnesium oxide(MgO)
Now, we have to, somehow, get Magnesium oxide using Oxygen. The best way is: by reacting Magnesium with Oxygen.
- Iron(Fe) + Sulfur(S) ---> Iron Sulfide(FeS)
Now, we have to get two reactants that react to form Iron Sulfide.
FeS contains only two elements in its formula and that are: Iron(Fe) and Sulfur(S).
So, the best way would be to react Iron(Fe) and Sulfur(S) and get Iron Sulfide (FeS)
- Hydrogen(H2) + Oxygen(O2) ---> water(H2O)
You must know that water is H2O, that is, a compound of Hydrogen and Oxygen, the easiest way to get H2O as your product would be : by reacting Oxygen and Hydrogen.
