What is the molar mass of pure nitrogen gas? (*diatomic element) ???
The Correct Answer and Explanation is:
The molar mass of pure nitrogen gas (N₂) is 28.014 g/mol .
Explanation
Molar mass is a fundamental concept in chemistry that defines the mass of one mole of a substance. A mole represents a specific quantity of particles, namely Avogadro’s number (approximately 6.022 x 10²³ particles), and the molar mass is typically expressed in units of grams per mole ( g/mol ).
To determine the molar mass of a substance, one must first look at the periodic table for the atomic mass of its constituent elements. The atomic mass listed for nitrogen (N) is approximately 14.007 atomic mass units, which corresponds to a molar mass of 14.007 g/mol for a single mole of individual nitrogen atoms.
However, the crucial point for nitrogen gas is its natural state. Under standard conditions, nitrogen is a diatomic molecule. This means it does not exist as single, independent atoms but rather as molecules composed of two nitrogen atoms chemically bonded together. The chemical formula for nitrogen gas is therefore written as N₂.
Consequently, to find the molar mass of the entire nitrogen molecule (N₂), the molar mass of a single nitrogen atom must be multiplied by two. The calculation is as follows:
Molar Mass of N₂ = 2 × (Molar Mass of a single N atom)
Molar Mass of N₂ = 2 × 14.007 g/mol
Molar Mass of N₂ = 28.014 g/mol
Therefore, one mole of pure nitrogen gas, which contains 6.022 x 10²³ molecules of N₂, has a collective mass of 28.014 grams. This value is essential for stoichiometric calculations involving reactions with nitrogen gas.
