Question

How many oxygen atoms are in carbon dioxide?

Answer 1

Mole is defined as the unit of measurement which helps in calculating the number of particles present in its substance. The amount of substance present in 1 mole of substance is equal to the amount of substance present in 12g of carbon 12 atom. The 1 mole is equal to Avogadro number which is equal to $6.023 \times {10^{23}}$ elementary entities.

Complete step by step answer:
So the mole is the unit of the measurement of the amount of substance according to the International System of units. Those elementary entities in the Avogadro number can be either molecules or the atoms or the ions. We can calculate the number of moles in the substance by just dividing the given mass by molecular mass.
but here first we need to find the number of atoms present in the 1 mole of carbon dioxide then multiplying it by the Avogadro number. So the formula of carbon dioxide is $C{O_2}$. This shows that it contains 2 atoms of oxygen. even the word di in dioxide represents 2.
So 1 mole of carbon dioxide contains = 2 atoms of oxygen
So 1 atom of oxygen has = $6.023 \times {10^{23}}$elementary entities (atoms, molecules, ions, etc)
So 2 atoms of oxygen has = $6.023 \times {10^{23}} \times 2 = 12.046 \times {10^{23}}$elementary entities.

So we have $12.046 \times {10^{23}}$ atoms of oxygen in carbon dioxide.

Note: We see that in one molecule of carbon dioxide we have 2 atoms of oxygen so it is known as atomicity. This is the number of the atoms which constitute the molecule. We can determine it by the ratio of the molecular mass to the mass of an atom.