Final answer:
To find moles from molecules, divide the number of molecules by Avogadro's number. To find molecules from moles, multiply the number of moles by Avogadro's number. Both answers would give very small or very large numbers, respectively.
Step-by-step explanation:
To find the number of moles in 1.26 x 104 molecules of HC2H3O2, you need to use Avogadro's number, which is 6.022 x 1023 molecules/mol. To convert molecules to moles, divide the number of molecules by Avogadro's number:
Moles of HC2H3O2 = (1.26 x 104 molecules) / (6.022 x 1023 molecules/mol)
This calculation results in a very small number of moles, which is expected since the number of molecules given is much less than a mole.
To find the number of molecules in 2.6 mol of LiBr, use Avogadro's number again:
Molecules of LiBr = (2.6 mol) x (6.022 x 1023 molecules/mol)
This calculation results in the number of molecules corresponding to 2.6 moles of LiBr.