Which one is correct? I have two different answers to the question: Is the number of particles per mole dependent on the kind of atom/element? Why or why not?

Question

No, because the number of particles per mole is measured by the Avogadro Number. This means that one mole of any substance is equal to 6.022 × 10²³. Although the number of particles per mole is not dependent on the kind of atom/element, the number of particles, and therefore the number of moles, varies in any specific substance.

Yes, because the number of particles per mole differs in regards to the amount of an atom/element. The example used in the video stated that 6.022 × 10²³ can be measured by 18.01 grams, but if we were to add more or less than that, the number of particles in a mole would change.

This means that one mole is defined as the amount of substance from a certain element.

Answer 1

The confusion may come from asking about atoms, elements and compounds.

The number of particles per mole DOES NOT depend on the type of atom or element.

The number of particles per mole DOES depend on the type of molecule.

Examples:

1. How many particles in 1 mol of hydrogen? 1 mol H x 6.02x10²³ atoms/mole = 6.02x10²³ atoms = 6.02x10²³ particles in 1 mol of hydrogen
2. How many particles in 1 mol of lead? 1 mol Pb x 6.02x10²³ atoms/mole = 6.02x10²³ atoms = 6.02x10²³ particles in 1 mol of lead
3. How many particles in 1 mole H₂O? 1 mol H₂O x 6.02x10²³ molecules H₂O/mol = 6.02x10²³ molecules = 3 x 6.02x10²³ particles because each water molecule has 3 atoms = 1.8x10²⁴ particles in 1 mole of H₂O
4. How many particles in 1 mol C₂H₆? 1 mol C₂H₆ x 6.02x10²³ molecules/mol x 8 particles/molecule = 4.8x10²⁴ particles in 1 mole of C₂H₆

I hope I didn't make this more complicated than it already was, but sometimes the devil is in the details. The question is a little ambiguous as written. So, I think both answers can be correct.

Answer 2

The mole is a unit measure, just like a dozen. It doesn't matter what the item is - you can have a mole of silver atoms, water molecules, slinky toys, or presidents. If you have 6.022 x 10²³ of any of these items, you have 1 mole of them. The analogy is a dozen. You can have a dozen of anything.

What does change from one item to another, is the mass of a mole of those items. A mole of elephants has greater mass than a mole of water molecules. But each water molecule would have one elephant, since there are equal numbers of them.

Long story short, A is correct. B is incorrect since the mass for a mole changes depending on the item. A mole of carbon atoms is 12 grams, but a mole of sodium atoms is 32 grams. Both have a mole of atoms, but their masses are different.

Bob