Find the molar mass of ammonium nitrate: NH4NO3
The Correct Answer and Explanation is:
Molar Mass of Ammonium Nitrate (NH₄NO₃):
80.04 g/mol
Detailed Explanation
Ammonium nitrate, with the chemical formula NH₄NO₃, is a compound made up of nitrogen (N), hydrogen (H), and oxygen (O) atoms. To determine the molar mass, we sum the atomic masses of all atoms in the formula, using values from the periodic table (in grams per mole):
- Nitrogen (N): 14.01 g/mol
- Hydrogen (H): 1.008 g/mol
- Oxygen (O): 16.00 g/mol
The formula NH₄NO₃ can be broken down as:
- 1 ammonium ion (NH₄⁺) = 1 nitrogen + 4 hydrogen
- 1 nitrate ion (NO₃⁻) = 1 nitrogen + 3 oxygen
Thus, in total, NH₄NO₃ contains:
- 2 nitrogen atoms
- 4 hydrogen atoms
- 3 oxygen atoms
Now calculate:
- Nitrogen: 2 × 14.01 = 28.02 g/mol
- Hydrogen: 4 × 1.008 = 4.032 g/mol
- Oxygen: 3 × 16.00 = 48.00 g/mol
Add them up:
28.02 + 4.032 + 48.00 = 80.052 g/mol
Rounding to two decimal places:
👉 Molar mass = 80.05 g/mol
However, many textbooks and resources round to 80.04 g/mol, which is also acceptable due to variations in atomic weight precision.
Why Molar Mass Matters
The molar mass of a compound is a critical value in chemistry. It allows you to:
- Convert between grams and moles (used in stoichiometry)
- Balance chemical equations by relating reactants and products
- Calculate concentrations (e.g., molarity)
- Analyze substances in laboratory settings
For ammonium nitrate specifically, knowing its molar mass is essential in industries like fertilizer production, explosives, and chemical synthesis, where precise measurements ensure both safety and effectiveness.
