Oxygen has 8 electrons and each hydrogen has one. Thus a water molecule would have 10 electrons. Assuming volume of a cup of water to be 180 mL, this would mean 10 mole. of water. Since each molecule contain 10 electrons, one mole of water would contain 10 mole numbers of electrons and 10 moles of water would contain 100 mole numbers of electrons.
It depends on quantity