Question

Lysine is an amino acid that is an essential part of nutrition but which is not synthesized by the human body. What is the molar mass of lysine if 750.0 mL of a solution containing 8.60 g of lysine has an osmotic pressure of 1.918 atm? Temperature = 25.0°C

Answer 1

Molar mass of lysine is 146.267 grams per mole.

Step-by-step explanation:

Osmotic pressure(π) is given by the formula

π = cRT

where c is concentration in
`(moles)/(L)` (Molarity).

c = no of moles per volume in litres.

R is universal gas constant = 0.0821
`(L-atm)/(mole-K)`

T is temperature in K.

Substituting values in the above equation gives

1.918 =
`(8.6*1000)/(M*750)*0.0821*298`

M = 146.267 grams per mole.

Answer 2

The molar mass of lysine using the ideal gas equation for this problem is 146.25 g/mole.

Step-by-step explanation:

The ideal gas equation PV = nRT, was derived from the ABC laws (Avogadros, Boyles and Charles laws). We need to obtain the value for the number of moles n.

The parameters of this equation are:

P = 1.918 atm

V = 750.0mL = 0.75L

n = ?

R = 0.0821

T = 25 degree celcius = 25 + 273 = 298 degree kelvin.

From this formular, n = (PV)/(RT)

n = (1.918 X 0.75)/(0.0821 X 298 )

n = 0.0588

n, no of mole = mass/molar mass

0.0588 = 8.6/MM

MM = 8.6/0.0588

MM = 146.25g/mole.