What is the difference between formula mass and molecular mass?

Question

Answer

Answer

Formula mass is defined as the sum of atomic masses of the ions present in the formula unit of an ionic compound while molecular mass is the sum of the atomic masses of the atoms in a molecule. Formula mass is more general term than molecular mass and maybe used in referring to all compounds but not the molecular mass

Answer

Formula Mass:
Formula mass is the sum of the atomic masses of all the atoms in a chemical formula. It is also known as the empirical formula mass or the molecular formula mass. Formula mass is used for ionic compounds and molecules that do not exist as discrete entities.

Molecular Mass:
Molecular mass is the sum of the atomic masses of all the atoms in a molecule. It is also known as the molecular weight or the molar mass. Molecular mass is used for covalent compounds and molecules that exist as discrete entities.

Difference between Formula Mass and Molecular Mass:

Definition:
- Formula mass is the sum of the atomic masses of all the atoms in a chemical formula.
- Molecular mass is the sum of the atomic masses of all the atoms in a molecule.

Usage:
- Formula mass is used for ionic compounds and molecules that do not exist as discrete entities.
- Molecular mass is used for covalent compounds and molecules that exist as discrete entities.

Calculation:
- Formula mass is calculated by adding the atomic masses of the elements in the chemical formula.
- Molecular mass is calculated by adding the atomic masses of the elements in a molecule.

Representation:
- Formula mass is represented by a chemical formula, which shows the ratio of elements in the compound.
- Molecular mass is represented by a molecular formula, which shows the actual number of atoms of each element in the molecule.

Example:
- For example, the formula mass of sodium chloride (NaCl) is calculated by adding the atomic masses of sodium (22.99 g/mol) and chlorine (35.45 g/mol) to get a formula mass of 58.44 g/mol.
- For example, the molecular mass of water (H2O) is calculated by adding the atomic masses of hydrogen (1.01 g/mol) and oxygen (16.00 g/mol) to get a molecular mass of 18.02 g/mol.

Conclusion:
In summary, the main difference between formula mass and molecular mass lies in their usage and calculation methods. Formula mass is used for ionic compounds and molecules that do not exist as discrete entities, while molecular mass is used for covalent compounds and molecules that exist as discrete entities. Formula mass is calculated by adding the atomic masses of the elements in the chemical formula, while molecular mass is calculated by adding the atomic masses of the elements in a molecule.

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