To determine the molar mass of a protein, a 0.891 g sample of it is added to 5.00 g of water and the osmotic pressure is measured as 0.179 atm at 22.0°C, what is the molar mas of the protein? (The protein is non-ionizing)

Answer :

baraltoa

Answer:

MW = 24,097 g/mol

Explanation:

The osmotic pressure of a solution is given by the equation:

πV = nRT

where π is the osmotic pressure, V is the volume, R is the gas constant 0.08205 Latm/kmol , and T is the temperature.

n , the number of moles is equal to m/MW, substituting into the equation:

πV = ( mass/MW ) RT

MW = mass x R x T / ( πV  )

V is given by the density of solution assumed to be that of water:

d = m/v ⇒ v= m/d = 5.00 g / 1 g/mL = 5.00 mL

The volume we need to convert to liters for units consistency in the metric system:

5.00 mL x 1 L / 1000 mL = 5 x 10⁻³ L

solving for

MW = 0.891 g x 0.08205 Latm/Kmol x ( 22 + 273 )K / (0.179 atm x 5 x 10⁻³ L )

= 24,097 g/mol

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