Question: how many electrons in 1 kg of water?
Answer: 18 grams which contain 6.023*10^23 molecule of water . 18,000 grams contain 6.023* 10^26 molecule. Each molecule of water contain 2 atoms of hydrogen and one atom of oxyden. The total number of electrons in 1 molecule of water = 1+ 8 =9 electrons.