Martin S. answered • 03/29/20

Patient, Relaxed PhD Molecular Biologist for Science and Math Tutoring

To answer this, first calculate how many electrons are in 1 kg of water, then multiply that by the charge per electron (1.602 x 10^-19 coulombs).

The molecular weight of water is 18, so there are 1000 / 18 = 55.55 moles of water in 1 kg. Multiply that by Avogadro's number (6.02 x 10^23) to get the number of water molecules

55.55 x 6.02 x 10^23 = 3.34 x 10^26.

Each water molecule has 10 electrons, so multiply that answer by 10 to get the total number of electrons,

3.34 x 10^27 electrons per kg water.

Finally, multiply the number of electrons by the energy per electron (1.602 x 10^-19 coulombs).

3.34 x 10^27 electrons x 1.602 x 10^-19 coulombs/electron = 5.29 x 10^8 coulombs.