Suppose 10 mg of deprenyl is diluted in 10 mL of water. What is the a) mass fraction and b) mol fraction of deprenyl in the solution?

(a) Mass fraction of deprenyl in the solution is 0.55

(b) Mole fraction of deprenyl in the solution is0.11

Explanation:

(a) Mass of deprenyl = 10mg = 10/1000 = 0.01g

Volume of water = 10mL = 10/1000 = 0.01L

1 mole of a substance contains 22.4L of the substance

0.01L of water = 0.01/22.4 = 0.00045mole of water

MW of water = 18g/mole

Mass of water = 0.00045mole * 18g/mole = 0.0081g

Mass of solution = mass of deprenyl + mass of water = 0.01g + 0.0081g = 0.0181g

Mass fraction of deprenyl = mass of deprenyl/mass of solution = 0.01g/0.0181g = 0.55

(b) Molecular weight (MW) of deprenyl (C13H17N) = 187g/mole

Number of moles of deprenyl = mass/MW = 0.01/187 = 0.000053mole

Total moles of solution = moles of deprenyl + moles of water = 0.0000053mole + 0.00045mole = 0.000503mole

Mole fraction of deprenyl in the solution = moles of deprenyl/moles of solution = 0.000053mole/0.000503mole = 0.11