How much positive and negative charge …

Assume that one cup holds 250 ml of water.

250 ml = 250 gram of water since its density is 1 in cgs.

number of moles of water in 250 gram = 250 / molar weight of water

n = 250/18 = 13.88 moles

1 mol has 6.022 x 1023 number of water molecules

So 250 g water will have 13.88 x 6.022 x 1023 number of H2O molecules

= 8.36 x 1024 number of molecules

One molecule of water has 2 hydrogen atoms (2 protons) and one oxygen atom (8 protons).

Total protons = 10 = total electrons (since it is neutral)

So 250 g water will have 10 x 8.36 x 1024 = 8.36 x 1025 protons.

charge of proton = 1.6 x 10-19 C

So total positive charge of 250 g water = 1.6 x 10-19 x 8.36 x 1025 = 13.37 x 106 C

which is equal to 13.3 MC (mega coulomb)

So one cup of water has 13.3 mega coulomb positive and negative charge, so that the overall charge is zero.