There are a total of four atoms of hydrogen in 2H2O.
We can see that there are two atoms of hydrogen in one molecule of water (H2O) by the 2 added as a subscript beside H. But since there are two molecules of water in this case (2H2O), the number of hydrogen atoms is doubled.
In water, we also have one atom of oxygen. In two molecules of water, we would have two atoms of oxygen.
Thus the total number of atoms in one mole of water would be 3 (2H + O). In two molecules, the number would be doubled. That is to say, that there will be 6 atoms in total in 2 moles of water (3+3).
I hope you are clear on how we calculated the number of atoms for each element and the total.
We can see that there are two atoms of hydrogen in one molecule of water (H2O) by the 2 added as a subscript beside H. But since there are two molecules of water in this case (2H2O), the number of hydrogen atoms is doubled.
In water, we also have one atom of oxygen. In two molecules of water, we would have two atoms of oxygen.
Thus the total number of atoms in one mole of water would be 3 (2H + O). In two molecules, the number would be doubled. That is to say, that there will be 6 atoms in total in 2 moles of water (3+3).
I hope you are clear on how we calculated the number of atoms for each element and the total.
