The temperature of something.
To balance the the chemical reaction, the number of moles
per element is balance is both side of the reaction and also the charge in both
sides of the reation. to balnce the reaction:
S2O3 2- + Cu 2+ ---> S4O6 2- + Cu+
2S2O3 2- + Cu 2+ ---> S4O6 2- + Cu+ + e
To calculate the atomic mass of a single atom of an element, add up the mass of protons and neutrons.