Calculate The Molecular Mass of The Following Nh3

Ammonia (NH3) is a common chemical compound with important industrial and biological applications. Calculating its molecular mass is fundamental to chemistry. This guide explains how to compute the molecular mass of NH3 using atomic weights and provides a step-by-step calculator.

How to Calculate Molecular Mass

The molecular mass of a compound is the sum of the atomic masses of all atoms in its molecular formula. For NH3 (ammonia), the formula shows one nitrogen atom and three hydrogen atoms.

Formula for Molecular Mass

Molecular Mass = (Number of Nitrogen Atoms × Atomic Mass of N) + (Number of Hydrogen Atoms × Atomic Mass of H)

To calculate the molecular mass of NH3:

Identify the number of each type of atom in the formula.
Find the atomic mass of each element from the periodic table.
Multiply the number of each atom by its atomic mass.
Sum the results to get the molecular mass.

Note: Atomic masses are based on the standard atomic weight values from the latest IUPAC periodic table.

Calculating NH3 Molecular Mass

For ammonia (NH3):

1 nitrogen (N) atom
3 hydrogen (H) atoms

Using standard atomic weights:

Atomic mass of N = 14.0067 g/mol
Atomic mass of H = 1.00784 g/mol

The calculation is:

Molecular Mass of NH3 = (1 × 14.0067) + (3 × 1.00784)

= 14.0067 + 3.02352

= 17.03022 g/mol

The molecular mass of NH3 is approximately 17.03 g/mol.

Formula for Molecular Mass

The general formula for calculating molecular mass is:

Molecular Mass = Σ (Number of Atoms of Element × Atomic Mass of Element)

For NH3:

Molecular Mass = (1 × Atomic Mass of N) + (3 × Atomic Mass of H)

This formula applies to all chemical compounds, not just ammonia.

Worked Example

Let's calculate the molecular mass of methane (CH4) as another example.

For CH4:

1 carbon (C) atom
4 hydrogen (H) atoms

Using standard atomic weights:

Atomic mass of C = 12.0107 g/mol
Atomic mass of H = 1.00784 g/mol

The calculation is:

Molecular Mass of CH4 = (1 × 12.0107) + (4 × 1.00784)

= 12.0107 + 4.03136

= 16.04206 g/mol

The molecular mass of CH4 is approximately 16.04 g/mol.

FAQ

What is the molecular mass of NH3?: The molecular mass of ammonia (NH3) is approximately 17.03 g/mol, calculated by summing the atomic masses of one nitrogen and three hydrogen atoms.
How do I calculate molecular mass?: To calculate molecular mass, multiply the number of each atom in the formula by its atomic mass, then sum these values. For NH3: (1 × 14.0067) + (3 × 1.00784) = 17.03022 g/mol.
Where can I find atomic masses?: Atomic masses are available from the latest IUPAC periodic table. For nitrogen, it's 14.0067 g/mol, and for hydrogen, it's 1.00784 g/mol.
Is molecular mass the same as molar mass?: Yes, molecular mass and molar mass are terms used interchangeably to describe the mass of one mole of a substance.
Why is molecular mass important in chemistry?: Molecular mass helps determine stoichiometry, reaction ratios, and solution concentrations in chemical calculations.