Question

How many moles of phosphorus trichloride would contain $3.35 \times {10^{24}}$ molecules of phosphorus trichloride?

Answer 1

This question can easily be solved with the application of the mole concept. A basic information about mole is required to arrive at the solution of this question. $1 {\text{mole}} = 6.022 \times {10^{23}} {\text{molecules}}$

Formula Used:
${\text{moles}} = \dfrac{{{\text{no of atoms}}}}{{{{\text{N}}_{\text{A}}}}}$

Complete step-by-step answer: We know that $1$ mole of any substance means $6.022 \times {10^{23}}$ entities of that substance. A mole is defined in the field of chemistry as the quantity of a substance containing exactly $6.022 \times {10^{23}}$'elementary entities' of the substance given.
We know that $6.022 \times {10^{23}}$ molecules in $1$ mole of molecules
And we have to find out the number of moles in $3.35 \times {10^{24}}$ molecules
We can do that by the simple mathematics unitary method conversion
That is
Number of moles in $3.35 \times {10^{24}}$ molecules$= \frac{{1 {\text{mol}} PC{l_3}}}{{6.022 \times {{10}^{23}}}} \times 3.35 \times {10^{24}}$
Upon solving, we get $5.56$ moles of $PC{l_3}$
Hence, there are $5.56$ moles of $PC{l_3}$ in $3.35 \times {10^{24}}$ molecules of phosphorus trichloride.

Additional Information:
The number $6.022 \times {10^{23}}$ is commonly referred to as the constant of Avogadro and is often denoted by the '${N_A}$' symbol. Atoms, molecules, monatomic/polyatomic ions, and other particles can be the fundamental entities (such as electrons) that can be represented in moles.

Note: Even one gram of a pure element is known to contain an enormous number of atoms when dealing with particles at an atomic (or molecular) level. This is where it is widely used to use the mole concept. It focuses primarily on the unit known as a mole, which is a very large number of particles counted.