How many hydrogen atoms are in 7.40 mol of ammonium sulfide?

Answer 1

The formula unit, which is the usual meaning of "mol" for an ionic compound such as ammonium nitride, is (NH4)2S. This shows that there are 2 X 4 or 8 hydrogen atoms in each formula unit. Avogadro's Number, which is about 6.022 X 1023, is the number of atomic formula units per mole. Therefore, the number of hydrogen atoms in 7.40 mol of ammonium sulfide is (8)(7.40)(6.022 X 1023) or 3.57 X 1025, to the justifiable number of significant digits. (The integer 8 is exact.)

Answer 2

There are 4 hydrogen atoms in one molecule of ammonium sulfide (NH4)2S. Therefore, in 7.40 mol of ammonium sulfide, there would be 4 * 7.40 = 29.6 mol of hydrogen atoms. To find the number of hydrogen atoms, we multiply by Avogadro's number (6.022 x 10^23) to get approximately 1.78 x 10^25 hydrogen atoms.