Question

Calculate the volume occupied by
A. $28u$ Nitrogen gas
B. $28g$ nitrogen gas at STP

Answer 1

Hint: nitrogen is an element having atomic number $7$ . It contains five valence electrons in $2s$ and $2p$ orbital.
STP stands for standard temperature and pressure. It is defined as the temperature at zero degree and pressure at one atmosphere of pressure.

Complete step by step answer:
An atomic mass unit is defined as the masses of molecules and atoms which are equal to the $\dfrac{1}{12}$ of the mass of the carbon atom in its ground state. It is denoted with a symbol $u$
A. The mass of nitrogen is $28u$
$1$ mole of nitrogen contains $28u$
$1$ mole of nitrogen gas occupies at STP $=22.4l$
As we know that, $1$ mole contains $6.022\times {{10}^{23}}$ molecules
Now, we will substitute the value of one mole we get,
$6.022\times {{10}^{23}}$ molecules of nitrogen occupies $=22.4l$
B. $1$ molecules of nitrogen at STP occupies $=\dfrac{22.4}{6.022\times {{10}^{23}}}$
$1$ molecules of nitrogen at STP occupies $=3.72\times {{10}^{-23}}l$
Therefore, volume occupied by $28u$ Nitrogen gas $=3.72\times {{10}^{-23}}l$
$1$ mole of nitrogen gas $\left( {{N}_{2}} \right)$ contains $=28g$
$1$ mole of nitrogen gas occupies at STP $=22.4l$
Therefore, $28g$ of nitrogen gas at STP contains $22.4l$

Additional information:
Moles is defined as the scientific unit which is used to measure large quantities of atoms, ions and molecules. It is defined as the amount of substance present in a sample. $1mole=6.022\times {{10}^{23}}$ particles.
It is calculated by the weight of the compound to the molar mass of the compound.
Mole is very important because it helps to study atoms, molecules and ions.

Note: Avogadro's number is defined as the proportionality factor that tells the relationship between the number of constituent particles with the amount of substance in a sample. Its SI unit is $mo{{l}^{-1}}$ . It is denoted with a symbol ${{N}_{A}}$
It is the number of units in a mole of any substance.