The brain is part of the central nervous system.
Nerves and sensors are part of the peripheral nervous system. Only the brain and spinal cord make the central nervous system.
The problem you have written you almost have it solved. Take the moles that you have calculated and multiply that by the molecular weight to get the grams.
The STP problem:
use the moles you calculated along with 1 atm for Pressure, and 273 for the temperature and plug into the PV = nRT equation. (also use 0.0821 for R)
From there you can solve for the volume
Hope this helps!
The most likely answer is the boiling point and freezing point of water. The Celsius scale starts at the freezing point of water (0°C) and than scaled so that 100°C fell on the boiling point of water.
I hope this helps. Let me know if anything is unclear.
?????¿????????????????????