What is the total charge (in coulombs) on all the electrons in 3.0 kg of water?

Question

Do I have to find the number of electrons in the 3kg of Water first, and then multiply that by the charge of an electron?

Answer 1

Yes. Start with the mass of a molecule of water:

Mass of oxygen atom + 2x mass of hydrogen = 16 amu + 2 amu = 16 *1.67x10^-27 kg + 2* 1.67x10^-27 kg = 3 x10^-26 kg/molecule

So there are

3kg/(3x10^-26 kg/molecule) = 10^26 molecules of water in 3 kg of water.


Now each molecule has 8 electrons from the oxygen atom plus 2 electrons fromt eh hydrogens for a total of 10 electrons.

So the total number of electrons is 10* 10^26 = 10^27.

The total charge is 1.6x10^-19 *10^27 = 1.6x10^8 coulombs

Answer 2

each and each electron has mass = 9.1x10^-31 Kg. one hundred ten kg electrons might have one hundred ten/9.a million = 12 electrons. each and each has a million.6x10^-19 coulomb quantity of detrimental cost. So entire cost could be = 12 x a million.6 x 10^-19 = 19.2 x 10^-19 = a million.ninety two micropicocoulomb!