In the name of Allah
Physical chemistry- 2nd stage
Lecture No. 14 Liquids and solutions 3-4-2018
Assistance prof. Dr. Luma Majeed Ahmed
[email protected],
[email protected]
Effect of ionic compounds A tenth of a mole of sugar or a tenth of a mole of glycerine dissolved in water will have exactly the same effect on the boiling and freezing points even though sugar is a much bigger molecule. -However, a tenth of a mole of an ionic compound such as NaCl,, has an effect on the melting and boiling points that is almost twice what we would observe for sugar. ◦The simple reason for this effect is that salt ionizes into Na+ and Cl- ions in water ◦these ions act as independent particles on the vapor pressure of water. ◦Thus, to a first approximation, we may simply multiply the concentration of the salt by the number of ions it will form when dissolved in water. ◦Thus NaCl, NaNO3, and CaCO3 would have multipliers of two, while Na2SO4, and CaCl2 would have multipliers of three
Q/ Osmatic pressure of a solution containing 7 g of dissolved protein Per 100 cm3 of a solution is 25 mmHg at body temperature 310 K. calculate The molar mass of the protein
Problem: A 35.0-g sample of hemoglobin is dissolved in enough water to make 1.00 L of solution. P is measured to be 10.0 mm Hg at 25.0 ˚C. Calculate the molar mass of hemoglobin.
Q//A dilute aqueous solution of a non-dissociating compound contains 1.19 g of the compound per liter of solution and has an osmotic pressure of 0.0288 atm at a temperature of 37°C. Compute the molar mass of the compound
