What is the Difference Between Gram Atomic Mass and Gram Molecular Mass?

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The difference between gram atomic mass and gram molecular mass lies in the units of measurement and the substances they represent.

  • Gram Atomic Mass: This is the atomic weight of an element in grams. It represents the mass of a single atom of that element. To express atomic mass in grams, you can use the following formula: Mass of the element (in g) = Number of gram atoms / Atomic mass of the element (in g).
  • Gram Molecular Mass: This is the mass of one mole of a substance in grams. It represents the mass of a group of atoms or molecules. The gram molecular mass can be determined using the molecular formula of a substance. To find the gram molecular mass, look up each element's relative atomic mass in the formula, multiply the subscript following each element symbol (the number of atoms) by the atomic mass of that element, and add all the numbers together to get the gram molecular mass.

In summary:

  • Gram atomic mass represents the mass of a single atom of an element in grams.
  • Gram molecular mass represents the mass of one mole of a substance in grams.

Comparative Table: Gram Atomic Mass vs Gram Molecular Mass

The difference between gram atomic mass and gram molecular mass lies in the fact that gram atomic mass gives the mass of an individual atom, while gram molecular mass gives the mass of a group of atoms or molecules. Here is a summary of the two concepts:

Concept Description
Gram Atomic Mass The mass of one atom of an element, expressed in grams. It is numerically equal to the atomic mass of the element.
Gram Molecular Mass The mass of one mole of a substance, expressed in grams. It is the sum of the masses of all atoms in a mole of the substance.

To illustrate the difference, let's consider an example:

  • Hydrogen (H): The atomic mass of hydrogen is approximately 1 amu (atomic mass unit). The gram atomic mass of hydrogen is 1 gram (since 1 amu is equal to 1 gram).

  • Water (H2O): Each water molecule has 2 hydrogen atoms and 1 oxygen atom. The atomic mass of hydrogen is approximately 1 amu, and the atomic mass of oxygen is approximately 16 amu. The molecular mass of water is 2 + 16 = 18 amu. The gram molecular mass of water is 18 grams (since there are 2 hydrogen atoms and 1 oxygen atom in a water molecule, and their combined atomic masses are 18 amu).

In summary, gram atomic mass refers to the mass of an individual atom, while gram molecular mass refers to the mass of a group of atoms or molecules in a substance.