Potassium hydroxide (KOH) is formed when Potassium forms ionic bonds with OH-ions while Potassium Oxide (K2O) is formed when potassium forms ionic bonds with the Oxide (O2-) ions. i.e. This reaction is a neutralization reaction and occurs when an acid (HCl) reacts with a base (KOH).
A residue from a gunshot is most likely gun powder, which tells you what kind of bullet was shot and the type of gun that was used to shoot the target/victim/person. Some complications may be that there is more than one gun or weapon which uses that residue, so it may be hard to pinpoint it and the bullet can't really tell you who it is unless there's DNA on the bullet, and the chemicals of the bullet may even destroy evidence.
Answer : The products are Silver sulfide,
and Sodium iodide,
.
Explanation :
The given balanced chemical reaction is,

From the given balanced reaction, we conclude that the 2 moles of silver iodide react with the 1 mole of sodium sulfide to give product as 1 mole of silver sulfide and 2 moles of sodium iodide.
In a chemical reaction, reactants are represent on the left side of the right-arrow and products are represent on the right side of the right-arrow.
Therefore, in a chemical reaction the products are Silver sulfide and Sodium iodide.
Answer:
Electrons in a hydrogen atom must be in one of the allowed energy levels. If an electron is in the first energy level, it must have exactly -13.6 eV of energy.
...
Energy Levels of Electrons.
Energy Level Energy
1 -13.6 eV
2 -3.4 eV
3 -1.51 eV
4 -.85 eV