The law is approximately valid for real gases at sufficiently low pressures and high temperatures. The specific number of molecules in one gram-mole of a substance, defined as the molecular weight in grams, is 6.02214076 × 1023, a quantity called Avogadro's number, or the Avogadro constant.
Moles of water atoms = mass/molecular weight = 105/18 = 5.83 mol. Number of moles of hydrogen in water = 2 x moles of water = 11.66. Number of H atoms in water = moles of hydrogen x 6.02 x 10^23 = 7.019 x 10^24 ~ 7.02 x 10^24 atoms. Hope this helps.
Answer:
the original answer is 38.9km (3sf)
