The reaction that releases energy as heat is called an Exothermic reaction. This reaction does obey the law of conservation by preserving the energy present in the molecule and converting it to thermal heat to maintain it's from. Most reactions obey the law of conservation of energy.
3.8 Meters converts to 380 Centimeters.
If you are talking about an atom with a full octet, then it would just have a full shell of 8 valence electrons.
This must be a universal indicator, the pH is going down everytime you add more :)