Answer:
The molar mass of met-enkephalin is 573 g/mol
Explanation:
Step 1: data given
Volume of the aqueous solution = 20.0 mL = 0.02 L
Mass of met-enkephalin = 15.0 mg = 0.015 grams
Temperature = 298 K
Water column is 32.9 cm high
The density of mercury at 298K is 13.534 g/mL
Step 2: The osmotic pressure
P = cRT
⇒ with P = the osmotic pressure
⇒ with c is the concentration in mol/L
⇒ with R is the gas constant (L.atm/mol.K)
⇒with T the temperature (K)
if the water column is 32.9 cm = 32.9/13.534 mmHg. = 0.032 atm
⇒ Pressure = 0.032 atm
⇒ 0.032 atm = c * 0.08206 L*Atm/K*mol
⇒ T =t the temperature = 298 K
c = P/ RT
c = 0.032atm / (0.08206*298)
c = 0.00131 M
Step 3: Calculate moles
Moles = Molarity * volume
Moles = 0.00131 M * 0.020 L
Moles = 0.0000262 moles
Step 4: Calculate molar mass
Molar mass = mass / moles
Molar mass = 0.015 grams / 0.000026 moles
Molar mass = 573 g/mol
The molar mass of met-enkephalin is 573 g/mol
