Question

How many molecules are in 2.00 moles of $N{O_2}$ ?

Answer 1

Moles is defined as the basic and convenient unit for measuring the large number of the atoms and molecules. The 1 mole of the substance is equal to Avogadro number. The Avogadro number is equal to $6.023 \times {10^{23}}$ elementary entities. These elementary entities can be atoms, molecules and ions.

Complete step by step answer:
So to approach this question we need to calculate the number of molecules which are present in 1 mole of the substance. We know that according to mole concept
1 mole of the substance will contain = $6.023 \times {10^{23}}$ molecules of the substance so,
1 mole of the $N{O_2}$ (nitrogen dioxide) will contain = $6.023 \times {10^{23}}$ molecules of the $N{O_2}$ so,
2.00 mole of nitrogen dioxide will contain =$6.023 \times {10^{23}} \times 2 = 12.046 \times {10^{23}}$ molecules

So we conclude that 2.00 moles of nitrogen dioxide will contain $12.046 \times {10^{23}}$ molecules of the nitrogen dioxide.

Additional information:
The moles can be calculated by dividing the given mass by the molar mass of the substance. If the question was to calculate the given mass of the substance. Then we would have multiplied the number of moles by the molar mass of nitrogen dioxide. The molar mass of nitrogen dioxide is 46g.

Note: if the question was to tell the volume of the nitrogen dioxide then we would have multiplied the number of moles by the 22.4L. If the number of molecules was asked in the question then we would have multiplied the moles by the Avogadro number. The Avogadro number is equal to $6.023 \times {10^{23}}$elementary entities.