Calculate the temperature when ice will begin to separate from a mixture with mass percent of glycol in water used in the car radiator. K f for water = . K Kg mol - Unit Unit - - - - and molar mass of ethylene glycol is g mol - . Weight of solute (W ) = mass percent of solution means g of ethylene glycol Weight of solvent (water) W = - = g ΔT f = K f m M × W K f × W × .
× × × = . K The temperature at which ice will begin to separate is the freezing point of water after the addition of solute i.e . K lower than the normal freezing point of water ( - .5K) = . K ?
) 2g of a non electrolyte solute dissolved in g of benzene lowered the freezing point of benzene by . K. The freezing point depression constant of benzene is . K Kg mol - .
Find the molar mass of the solute. Evaluate Yourself Osmosis and osmotic pressure Many biological processes depend on osmosis, which is a spontaneous process by which the solvent molecules pass through a semi permeable membrane from a solution of lower concentration to a solution of higher concentration. The name osmosis is derived from the Greek word ‘ osmos ’ which means ‘to push’. It is also important to know that the semipermeable membrane selectively allows certain molecules in the solution to pass through it but not others.
Figure . Osmosis and osmotic pressure Let us consider a simple apparatus as shown in the above figure. A semipermeable membrane separates a chamber into two compartments. Water (pure solvent) is added to the first compartment and the aqueous NaCl (solution) is added to the second compartment such that the liquid levels on the both sides are equal.
Since there is a difference in concentration between the liquids present in the two compartments, the