Answer: 
Explanation:
25.3% Mg
74.7% Cl
First step: change % to g
25.3g Mg
74.7g Cl
Second step: calculate g/mol of each compound. You can do this by using the atomic mass.


Third step: determine the lowest number and divide everything by it. Of the result, extract whole number only.


Fourth step: Write each compound with their respective number below.
This empirical formula should be: 
Answer:
Hydrogen sulfide
Explanation:
A nonoxidizing acid is the acid which cannot act as oxidizing agent and thus furnish hydrogen ions. Example: HCl
Iron(II) sulfide reacts with nonoxidizing acid, say hydrochloric acid to give rotten egg smelling gas, H₂S (Hydrogen sulfide).
The reaction is shown below:
FeS (s) + 2HCl (aq) ⇒ FeCl₂ (s) + H₂S (g)
A general reaction is also shown below of the reaction of Iron(II) sulfide with any nonoxidizing acid, HX as:
FeS (s) + 2HX (aq) ⇒ FeX₂ (s) + H₂S (g)
Answer: The answerer is CH4 + 2O2 → CO2 + 2H2O
Explanation: }