One cup tea contains how many positive charge and how many negative charge

2 answers

It is about 250ml, or 250grams, or 250/18 moles.
Each mole has 6.02*10^23 molecules.
each molecule has (H2O) 18+ charges (Protons) and 18 - charges (electrons).
Answer: (250/18)*Avagrado's Number*18 positive, and the same number negative.
"tea leaves can also accumulate trace metal ions, such as cadmium 1, 5-9, cobalt 5-8, lead 1, 6-8, nickel 1, 6, 7, 9, copper [1, 5-7, 9, and aluminium 1, 6, which can be a threat to the human health" these are only metals, so no negative charges. metals form positive ions as they lose electrons
trace element/amount is one whose average concentration is less than 100 parts per million (ppm) measured in the atomic count or less than 100 micrograms per gram.

cobalt (2.5+ is average charge)
lead (3+ is average charge)
nickel(1.5+)
copper(2+)
cadmium(2+)
aluminium(3+)

assume each element is present as 10 micrograms per gram
=0.00001g of each
so i can only be bothered doing this with weight of aluminium, but it'll give a close enough answer
2.2277778x10^22 al ions in 1 gram (2.2277778x10^22)x3 (al3+) = positive charges in 1 gram = 6.6833333x10^22
this is a close enough idea a bit too large as the other metals have lower average charges, but not too much lower so as to give a wildly different result.
divide that by the viable value for a trace amount per gram = 1/0.00001=100000 so divide by 100000 =6.6833333x10^17
multiply this by the weight of an average cup of tea (minus the cup)
(6.6833333x10^17)x200 = 1.3366667x10^20
therefore a 200 gram cup of tea contains 1.3366667x10^20 positive charges.