Answer:
(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
