Atomic Weight

* Definition: The average mass of an atom of an element, taking into account the relative abundance of its isotopes.

* Units: Atomic mass units (amu) or grams per mole (g/mol)

* Focus: Individual atoms

* Example: The atomic weight of carbon is 12.011 amu. This is because carbon exists in two main isotopes: carbon-12 (12 amu) and carbon-13 (13 amu), with carbon-12 being much more abundant.

Mass Molar Molecular Weight

* Definition: The mass of one mole of a molecule. It's the sum of the atomic weights of all the atoms in a molecule.

* Units: Grams per mole (g/mol)

* Focus: Molecules

* Example: The mass molar molecular weight of water (H₂O) is 18.015 g/mol. This is calculated by adding the atomic weights of two hydrogen atoms (1.008 amu each) and one oxygen atom (15.999 amu).

Key Differences

1. Focus: Atomic weight deals with individual atoms, while mass molar molecular weight focuses on molecules.

2. Calculation: Atomic weight is an average based on isotope abundance, while mass molar molecular weight is the sum of atomic weights.

3. Units: Both can be expressed in grams per mole (g/mol), but atomic weight is also commonly expressed in atomic mass units (amu).

In Summary:

* Atomic weight is the average mass of an atom of an element.

* Mass molar molecular weight is the mass of one mole of a molecule.

Let me know if you have any more questions!