Hello!
To solve this question, we need to use the Avogadro's Number, which is a constant first discovered by Amadeo Avogadro, an Italian scientist. He discovered that in a mole of a substance, there are 6,02*10²³ molecules. Using this relationship, we apply the following conversion factor:
[tex]8,50* 10^{24}molecules* \frac{1 mol Na_2SO_3}{6,02* 10^{23}molecules}=14,12 molesNa_2SO_3 [/tex]
So, 8,50 * 10²⁴ molecules of Na₂SO₃ represent 14,12 moles of Na₂SO₃
Have a nice day!