The average osmotic pressure of human blood is 7.7 atm at 40^(@)C. (a) What would be the total concentration of the various solutes in the blood ? (b) Assuming the concentration to be essentially the same as the molality, find the freezing point of blood (K_(f)" for water = "1.86^(@)C).

The average osmotic pressure of human blood is 7.7 atm at 40^(@)C. (a)

1.	The average osmotic pressure of human blood is 7.7 atm at 40^(@)C. (a) What would be the total concentration of the various solutes in the blood ? (b) Assuming the concentration to be essentially the same as the molality, find the freezing point of blood (K_(f)" for water = "1.86^(@)C).
Answer» Solution :(a) We are given that `"P = 7.7 atm, T"=40^(@)=C=40+273=313K` `"R = 0.0821 litre atm/degree/mole"` `"According to van't Hoff equation, "pi=CRT therefore C=(pi)/(RT)=("7.7 atm")/("0.0821 L atm K"^(-1)"mol"^(-1)xx313K)="0.30 mole/litre"` (b) Taking the molar concentration as equal to molality (Given), we have `"m = 0.30,"K_(f)=1.86^(@)C"(Given)"` `therefore""DeltaT_(f)=K_(f)xxm=1.86xx0.30=0.558^(@)C` `therefore"Freezing POINT of blood "=0^(@)C-0.558^(@)=-0.558^(@)C`