Question

how many O atoms are in 1.50 mol of sodium carbonate.

Answer 1

There are 2.71*10^24 atoms of oxygen.

1st) It is necessary to calculate the amount of oxygen in 1.50mol of sodium carbonate (Na2CO3).

We know that 1 mole of sodium carbonate has 3 moles of oxygen, so to calculate the moles of Oxygen in 1.50 moles of Na2CO3 we can use a mathematical Rule of Three:

$\begin{gathered} 1molNa_2CO_3-3molO \\ 1.5molNa_2CO_3-x=\frac{1.5molNa_2CO_3\cdot3molO}{1molNa_2CO_3} \\ x=4.5molO \end{gathered}$

Now we know that there are 4.5 moles of oxygen in 1.50 moles of sodium carbonate.

2nd) Finally, we can calculate the atoms of oxygen using the Avogadro's number (6.022*10^23 atoms/mol):

$\begin{gathered} 1\text{mol}-6.022\cdot10^{23}atoms \\ 4.5\text{mol}-x=\frac{4.5\text{mol}\cdot6.022\cdot10^{23}atoms}{1\text{mol}} \\ x=2.71\cdot10^{24}atoms \end{gathered}$

So, there are 2.71*10^24 atoms of oxygen in 1.50 mol of sodium carbonate.