How many atoms are there in 6.4 moles of H2?

7.71 ×10²⁴ atoms (3 s.f.)

Explanation:

Please see the attached picture for the full solution.

☆ or number of atoms, or fundamental units

(this is sometimes written as number of particles)

Further explanantion:

(☆:) Here, we are looking at the number molecules since H₂ is a molecule.

1 mole of a substance is the amount of substance which contains the same number of particles. Thus, when using Avogadro's Constant, the units that we are looking at follows the units of the question. Then, look at what the question is asking for and answer accordingly.

The 2nd picture shows an example of another molecule, H₂O.

Some other examples would be:

1 mole of Na (an atom) --- 6.022 ×10²³ atoms

1 mole of CO₂ (a molecule) --- 6.022 ×10²³ molecules

1 mole of Na+ --- 6.022 ×10²³ ions

Thus, if we look at the 2nd image again, we can say that 1 mole of H₂O contains 6.022 ×10²³ molecules since H₂O is a molecule. However, if the question is asking for the number of atoms, it is not right to say that there are 6.022 ×10²³ atoms. Instead, there are 1.2044 ×10²⁴ H atoms and 6.022 ×10²³ O atoms, giving us a total of 1.8066 ×10²⁴ atoms in 1 mole of H₂O.

frequency, z, and the collision density, z, in carbon dioxide (co2), r 180 pm at 30 °c and 120 kpa