Answer:
It depends what the compound is.
Explanation:
You need to use Avogadro's number (6.22*10^23) to convert the number of molecules of a compound to moles of the compound. From there, you can use the molar mass of the compound (grams per mole) to get the mass. You can get the molar mass by googling "molar mass of [compound]" or calculate it yourself using the periodic table.
So: 8.2*10^11 molecules of the compound * (1 mole of the compound/6.022*10^23 molecules of the compound) * (# of grams/1 mole of the compound)
