Out of BaCl2 and KC1, which one is more effective in causing coagulation of a negatively charged colloidal Sol? Give reason.

6-111 As noted in Section 6-8C, the amount of external pressure that must be applied to a more concentrated solution to stop the passage of solvent molecules across a semipermeable membrane is known as the osmotic pressure The osmotic pressure obeys a law similar in form to the ideal gas law (discussed in Section 5-4), where Substituting for pressure and solving for osmotic pressures gives the following equation: RT MRT, where M is the concentration or molarity of the solution. (a) Determine the osmotic pressure at 25°C of a 0.0020 M sucrose (C12H22O11) solution. (b) Seawater contains 3.4 g of salts for every liter of solution. Assuming the solute consists entirely of NaCl (and complete dissociation of the NaCI salt), calculate the osmotic pressure of seawater at 25°C. (c) The average osmotic pressure of blood is 7.7 atm at 25°C. What concentration of glucose (C6H12O6) will be isotonic with blood? (d) Lysozyme is an enzyme that breaks bacterial cell walls. A solution containing 0.150 g of this enzyme in 210. mL of solution has an osmotic pressure of 0.953 torr at 25°C. What is the molar mass of lysozyme? (e) The osmotic pressure of an aqueous solution of a certain protein was measured in order to determine the protein's molar mass. The solution contained 3.50 mg of protein dissolved in sufficient water to form 5.00 mL of solution. The osmotic pressure of the solution at 25°C was found to be 1.54 torr. Calculate the molar mass of the protein.

Predict the relative solubility of each compound in the two solvents, based on the intermolecular attractions. (a) Is potassium iodide more soluble in water or in methylene chloride (CH2Cl2)? (b) Is toluene (C6H5CH3) more soluble in benzene (C6H6) or in water? (c) Is ethylene glycol (C2H4(OH)2) more soluble in hexane (C6H14) or in ethanol (C2H5OH)?

For each of the following pairs of solutions, select the solution for which solute solubility is greatest. a. Ammonia gas in water with P = 1 atm and T = 50C Ammonia gas in water with P = 1 atm and T = 90C b. Carbon dioxide gas in water with P = 2 atm and T = 50C Carbon dioxide gas in water with P = 1 atm and T = 50C c. Table salt in water with P = 1 atm and T = 60C Table salt in water with P = 1 atm and T = 50C d. Table sugar in water with P = 2 atm and T = 40C Table sugar in water with P = 1 atm and T = 70C

For each of the following pairs of solutions, select the solution for which solute solubility is greatest. a. Oxygen gas in water with P = 1 atm and T = 10C Oxygen gas in water with P = 1 atm and T = 20C b. Nitrogen gas in water with P = 2 atm and T = 50C Nitrogen gas in water with P = 1 atm and T = 70C c. Table salt in water with P = 1 atm and T = 40C Table salt in water with P = 1 atm and T = 70C d. Table sugar in water with P = 3 atm and T = 30C Table sugar in water with P = 1 atm and T = 80C

A forensic chemist is given a white solid that is suspected of being pure cocaine (C17H21NO4, molar mass = 303.35 g/mol). She dissolves 1.22 0.01 g of the solid in 15.60 0.01 g benzene. The freezing point is lowered by 1.32 0.04C. a. What is the molar mass of the substance? Assuming that the percent uncertainty in the calculated molar mass is the same as the percent uncertainty in the temperature change, calculate the uncertainty in the molar mass. b. Could the chemist unequivocally state that the substance is cocaine? For example, is the uncertainty small enough to distinguish cocaine from codeine (C18H21NO3, molar mass = 299.36 g/mol)? c. Assuming that the absolute uncertainties in the measurements of temperature and mass remain unchanged, how could the chemist improve the precision of her results?

Distinguish between dispersion methods and condensation methods for preparing colloidal systems.

A solution is made by dissolving 0.455 g of PbBr2 in 100 g of H2O at 50C. Based on the data in Table 8-1, should this solution be characterized as a. saturated or unsaturated b. dilute or concentrated

Predict the relative solubility of each compound in the two solvents, on the basis of intermolecular attractions. (a) Is Br2 more soluble in water or in carbon tetrachloride? (b) Is CaCl2 more soluble in water or in benzene (C6H6)? (c) Is chloroform (CHCl3) more soluble in water or in diethyl ether [(C2H5)2O]? (d) Is ethylene glycol (HOCH2CH2OH) more soluble in water or in benzene (C6H6)?

Refer to Figure 13.10 ( Sec. 13-4b) to determine whether these situations would result in an unsaturated, saturated, or supersaturated solution. 120. g RbCl is added to 100. g H2O at 50 °C. 30. g KCl is dissolved in 100. g H2O at 70 °C. 20. g NaCl is dissolved in 50. g H2O at 60 °C. Figure 13.10 Solubility of ionic compounds versus temperature.