An aqueous salt solution has a freezing point of -.5 degrees Celsius and causes neither swelling or shriveling of cells. The kf of water is 1.86 K kg/mol. What is the osmotic pressure that is exerted on cells when placed in pure water? (ignore differences between molarity and molality)
Use delta T = i*Kf*m and calculate m.
Then use pi = i*mRT and solve for pi
would i=1 and delta t=.5 deg C?
Also, if it says that the experiment was performed at 273 K, would that be the value of T in the second equation?
yes
To calculate the osmotic pressure exerted on cells when placed in pure water, we need to use the formula:
π = osmotic pressure (in atm)
M = molarity of the solution (in mol/L)
R = ideal gas constant (0.0821 L·atm/(K·mol))
T = temperature (in Kelvin)
In this case, since the cells are placed in pure water, the molarity of the solution is zero. Thus, we can assume the osmotic pressure is zero as well.
Osmotic pressure (π) can be calculated using the formula:
π = i * M * R * T
Where:
i = van't Hoff factor, which represents the number of particles into which the compound dissociates (in this case, it is 1 because the solution does not dissociate into ions)
M = molarity of the solution (in mol/L)
R = ideal gas constant (0.0821 L·atm/(K·mol))
T = temperature (in Kelvin)
Since the molarity is zero and the van't Hoff factor (i) is 1, the osmotic pressure (π) will be zero as well.