How many moles of ethanol are in 5.20 X 1026 molecules of ethanol?

Answer 1

1 mole of anything is just Avogadro's number (N_A = 6.02 x 10²³) of that thing. In this case, we are told number of ethanol molecules and you want to convert to moles:

5.2 x 10²⁶ molecules Eth * (1 mole/N_A molecules of Eth) = 841 moles of Eth