Number one would be Decades
High temperature and low pressure<--Most likely
Low temperature and high pressure<----Less likely.
So the answer to this is Low temperature and high pressure.
Lithium's atomic weight is 6.94 g/mol.

Need anything else?
28 degrees below freezing would be 4 degrees
It runs from 0 to 14. (A)
It is based off the -log [H+] where [H+] is the concentration of the Hydrogen ions.