Question

How many moles are $1.20 \times {10^{25}}$ atoms of phosphorus?

Answer 1

A mole is one of the fundamental units which helps to calculate a big number. In any chemical reaction, the number of mole ratio of reactant and product is always fixed i.e., we always use a fixed number of molecules of reactant to form a fixed number of moles of product.

Complete step by step answer:
A mole is derived from a Greek word called Mol which means a heap or a pile. It is used to calculate a big number which is difficult to calculate in real terms. In the international System of Units called SI system, mole is one of the fundamental units which help us to calculate the big numbers. It is also called Avogadro’s number in respect of Amadeo Avogadro and one mole of any substance (atom, ions, molecules, electron, neutron, and proton) is equal to
$1\;mole\; = \;6.022 \times {10^{23}}$ particles
In chemistry, mole is widely used to calculate the amount of substance formed, volume of gas released at Standard temperature and pressure condition called STP, number of particles or molecules formed during a chemical reaction.
It also helps us to calculate the gram molecular mass and gram atomic mass of a substance in reference of $1/{12^{th}}\;of\;C - 12.$
Given: Number of phosphorus atom $= 1.20 \times {10^{25}}$ atom
Formula used:
Before calculating the number of moles of phosphorus atom, let us see the formula used to calculate the number of moles, which is as follows
Number of moles of phosphorus atom $=$ Number of phosphorus atom $/6.022 \times {10^{23}}$
Number of moles of phosphorus atom $= 1.20 \times {10^{25}}\;atom\;/6.022 \times {10^{23}}$
Number of moles of phosphorus atom $= 19.93$ mole of phosphorus atom
Final answer:
Number of moles of phosphorus atom $= 19.93$ mole

Note:
Mole can also be found in many ways. Number of moles $=$ mass of given atom / gram atomic mass
Number of moles $=$ mass of given molecules / gram molecular mass
Number of moles $=$ Given volume of gas at STP / molar volume of $22.4$ Liter