Vodka is a 6.86 M aqueous solution of ethanol. How many mL of ethanol are needed to make 500.0 mL of Vodka?

Question

Question:Vodka is a 6.86 M aqueous solution of ethanol. How many mL of ethanol are needed to make 500.0 mL of Vodka? (density of ethanol = 0.789 g/mL, C₂H₅OH: 46.07 g/mol)

Answer 1

6.86 M C2H5OH = 6.86 mols C2H5OH / Liter of solution

500.0 ml = 0.5000 L

6.86 mols / L x 0.5000 L = 3.43 mols C2H5OH required

Converting this to mls of C2H5OH, we have ...

3.43 mols C2H5OH x 46.07 g /mol x 1 ml / 0.789 g = 200. mls (to 3 sig. figs.)