Answer:
the second one ..........
Molecular formula of ascorbic acid is 
Molar mass of ascorbic acid = 
Converting 500.0 mg of ascorbic acid to moles: We use molar mass of ascorbic acid to convert mass to moles.

Converting 500.0 mg of ascorbic acid to molecules: The conversion factor used is 1 mole = 

Answer:
C:
Explanation:
Current flows from negative to positive.So the electrons will be moving left.
when a current is applied, positive charged copper ions (called cations) leave the anode (positive electrode) and move to the cathode (negative electrode).
2.5 x 10^24 molecules of C4H10