How many electrons does 1.00 kg of water contain?

6 x (10)^26 electrons.

Explanation:

1 mole = 18 gr

1 gm =1/18 mole

1 kg = 1000/18 mole

Now , 1 mole of any compound = 6.022 x (10)^23 atoms.

Therefore, 1 kg of H20= (1000/18)*(6.022 x (10)^23) atoms

Roughly , 3.34 x (10)^25 molecules

And each molecule has 18 electrons

Therefore, 6 x (10)^26 electrons.

Thank you.