Final answer:
The total charge of all the electrons in a 12-kg bar of gold can be calculated by multiplying the number of electrons by the charge of each electron. The net charge of the bar will be zero because gold is a neutral element.
Step-by-step explanation:
The total charge of all the electrons in a 12-kg bar of gold can be calculated using the relationship between charge and mass. The charge of an electron is -1.6 x 10^-19 C, so we can determine the total number of electrons in the bar of gold by dividing the mass of the gold (12 kg) by the atomic mass of gold (197 g/mol) and then multiplying by Avogadro's number (6.022 x 10^23 mol^-1). The net charge of the bar will depend on the number of electrons gained or lost, and since gold is a neutral element, the net charge of the bar will be zero.