(4) chemical energy to electrical energy is the correct answer.
Hope this helps~
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!
In photosynthesis, plants take in carbon dioxide and turn it into energy that comes out as oxygen.
4 grams , mass cannot be created or destroyed. it has to be the same on both sides of the equation