There are 1.204 x 10^24 atoms of hydrogen present in 18 grams of water. In order to calculate this, it is necessary to compute the number of hydrogen moles present in the sample.
Continue ReadingA molecule of water consists of a single atom of oxygen and two atoms of hydrogen. Oxygen has an atomic weight of 15.9994. One mole of oxygen, therefore, has a mass of just under 16 grams. Hydrogen has an atomic weight of 1.0079, and so a mole of hydrogen weighs just over 1 gram. This means that 18 grams of water contains one 16-gram mole of oxygen and two 1-gram moles of hydrogen. The number of particles in a mole is a constant known as Avogadro's number, which has a value of 6.022 x 10^23. Two moles of hydrogen, therefore, is double Avogadro's number.
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