Ch.12 - SolutionsWorksheetSee all chapters
All Chapters
Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds

The 4 Colligative Properties help to explain what happens to a pure solvent as solute is added to it.  

Properties of Solutions

Concept #1: The Colligative Properties. 

The four colligative properties of Boiling Point, Freezing Point, Vapor Pressure and Osmotic Pressure will either increase or decrease with the addition of solute to a pure solvent.  

Example #1: Explain what happens to each of the following properties as solute is added to a pure solvent.

a.  Boiling Point              b.  Freezing Point       

 

c. Osmotic Pressure        d. Vapor Pressure

 

 

Example #2: Which of the following compounds will have the highest boiling point?

a) 0.10 m sucrose

b) 0.10 m CsBrO­­3

c) 0.35 m CH3OH

d) 0.15 m SrBr2

Example #3: Pure water boils at 100oC. What is the expected boiling point of water after the addition of 13.12 g calcium bromide, CaBr2, to 325 g water. Kb = 0.512 oC/m. (MW of CaBr2 is 199.88 g/mol)

Example #4: The vapor pressure of water at 100.0oC is 0.630 atm.  Determine the amount (in grams) of aluminum fluoride, AlF3, (in grams) needed to reduce its vapor pressure to 0.550 atm. (MW of AlF3 is 83.98 g/mol)

Practice: Beta-carotene is the most important of the A vitamins. Calculate the molar mass of Beta-carotene if 25.0 mL of a solution containing 9.88 mg of Beta-carotene has an osmotic pressure of 56.16 mmHg at 30 degrees of Celsius.

Vapor Pressure

Vapor Pressure is achieved by the equilibrium rate of vaporization equaling the rate of condensation. 

Concept #2: Defining Vapor Pressure. 

Example #5: The vapor pressure of pure liquid A is 550 torr and the vapor pressure of pure liquid B is 320 torr at room temperature. If the vapor pressure of a solution containing A and B is 465 torr, what is the mole fraction of A in the solution?

Example #6: Determine the vapor pressure lowering associated with 1.32 m C6H12O6 solution (MW: 180.156 g/mol) at 25oC.

Practice: The following boiling points belong to one of the following compounds: 117°C, 78°C, 34.5°C and 23°C.

CH3-O-CH3                                                                

CH3CH2OH                               

CH3CH2-O-CH2CH3                            

CH3CH2CH2CH2OH

a)  Which boiling point goes with what compound?

b) If each of the following substances were placed in separate sealed clear bottles at room temperature, could you identify one of the substances right away? 

Additional Problems
Calculate the vapor pressure of a solution of 7.35g of aspirin (M = 180.15 g/mol) in 37.1 g of methanol (CH3OH) at 21.2°C. Pure methanol has a vapor pressure of 101 torr at this temperature. Assume that aspirin is NOT an ionic compound. A. 97.6 torr B. 84.3 torr C. 3.44 torr D. 16.7 torr E. 104 torr
Which of the following statements(s) is/are correct. i. A 0.45 m BaCl2 solution will have a lower freezing point than a 0.35 m K 2CrO4 solution. ii. A 0.35 M K2CrO4 solution will have a lower osmotic pressure than a 0.45 M BaCl 2 solution. iii. A 0.45 m K2CrO4 solution will have a higher boiling point than a 0.45 m BaCl 2 solution. A. i only B. ii only C. iii only D. i and ii E. ii and iii
The human eye has an osmotic pressure of 8.00 atm at 37.0 °C. What concentration (in moles/L) of a saline (NaCl) solution will provide an isotonic eyedrop solution? (Isotonic = a solution with equal osmotic pressure.) a) 0.0785 b) 0.157 c) 0.314 d) 0.786 e) 0.942
A compound is found to have a molar mass of 598 g/mol. If 35.8 mg of the compound is dissolved in enough water to make 175 mL of solution at 25°C, what is the osmotic pressure of the resulting solution? A. 3.42 torr B. 6.36 torr C. 5.01 torr D. 5.99 torr E. 8.36 torr    
What is the vapor pressure of a solution made by dissolving 48.4 g of glucose (C6H12O6) in 202.8 g of water at 22 oC. The vapor pressure of pure water at 22 oC is 92.50 mm Hg. A. 2.156 mm Hg B. 74.68 mm Hg C. 17.82 mm Hg D. 58.81 mm Hg E. 90.34 mm Hg
Water typically flows from a ______________solution to a ____________solution: A. Hypertonic; hypotonic B. Hypotonic; hypertonic C. Isotonic; isotonic D. Hypertonic; isotonic
What is the ideal van't Hoff factor for Mg(NO2)2? a) 2 b) 3 c) 4 d) 6 e) 7
Identify the correct van't Hoff factors for each compound.          CaSO 4              NiHPO4               SnF 2Br2 A.           2                        3                          2 B.           2                        2                          3 C.           4                        4                          4 D.            5                       2                          5 E.            2                       2                          5
A 0.86% by mass solution of NaCl is called "physiological saline" because its osmotic pressure is equal to that of the solution in the blood cells. Calculate the osmotic pressure of this solution at normal body temperature (37°C). Note that the density of the saline solution is 1.005 g/mL.   
The osmotic pressure of blood at normal body temperature of 37°C is 7.65 atm. Sometimes it is necessary to add a saline (NaCl) solution by intravenous injection to a patient in the emergency room. What should be the concentration of the NaCl solution (in g/L) so that it will have the same osmotic pressure as the blood at 37°C? a. none of the other answers is even close (within 10% error) b. 4.4 c. 2.2 d. 8.8 e. 17.6
Which statement is false? A) The vapor pressure of a solvent over a solution decreases as its mole fraction increases. B) The solubility of a gas increases as the temperature decreases. C) The vapor pressure of a solvent over a solution is less than that of pure solvent.  D) The greater the pressure of a gas over a solution the greater its solubility. E) Ionic solutes dissociate in solution causing an enhancement off all colligative properties.
The vapor pressure of pure ethanol [CH 3OH] at room temperature is 160.00 torr. What mole fraction of glycerol [C3H5(OH)3], a non volatile solute, is required to lower the vapor pressure to 86.00 torr at room temperature? A. 0.416 B. 0.462 C. 0.538 D. 0.584
Below is a U-tube where there are equal volume solution of 0.2M NaCL and 0.1M CaCl2 seperated by a membrance that only allows water through. In which direction will there be net movement of water? left    or   right
 A 0.100 m MgSO4 solution has a freezing point of -0.23°C. What is the van't Hoff factor for this solution? Kf = 1.86°C/m. A) 0.62 B) 1.0 C) 1.2 D) 2.0 E) 4.0
Identify the solute with the highest expected Van't Hoff factor. A) AlBr 3 B) KBr C) C 6 H 8 O 6 D) MgCl 2 E) NH 4 Cl
A solution of urea [(NH2)2CO] (MM: 60 g/mol) in water has a vapor pressure 2.50 mmHg less than that of pure water at 30°C (The vapor pressure of water at 30°C is 31.8 mmHg). a. What is the mole fraction of urea in this solution?     b. How many grams of urea does this correspond to?  
What is the expected Van’t Hoff factor for K 2CO3? A.  1                B.  2                 C.  3              D.  5                E.  6
The vapor pressure of pure acetone (CH 3COCH3) at 30°C is 240 torr. If salt (NaCl) is dissolve into a sample of acetone until the total vapor pressure of the mixture at 30°C is 180 torr, what is the mol fraction of acetone? 1. 0.2 2. 0.25 3. 0.8 4. 0.75
Kf = 1.86°C/m for water. We observe the freezing points of four different aqueous solutions as follows: Solution A freezes at -0.10°C Solution B freezes at -4.00°C Solution C freezes at -10.00°C; and Solution D freezes at -13.00°C. In each solution, the solute is a non-volatile non-electrolyte. Which solution should be expected to have the highest boiling point? 1. Solution D 2. Solution B 3. Solution A 4. Solution C  
Water typically flows from a ______________solution to a ____________solution:   A. Hypertonic; hypotonic B. Hypotonic; hypertonic C. Isotonic; isotonic D. Hypertonic; isotonic
If 2.00 mol of glucose (C 6H12O6) is dissolved in 0.500 kg of water, what is the vapor pressure of the solution? The vapor pressure of water at 25oC is 23.8 torr. A. 23.8 torr     B. 25.5 torr      C.  8.70 torr     D. 22.2 torr     E. 1.60 torr
At 25oC the vapor pressure of pure butane (C4H10, MW = 58.12 g/mol) is p°b = 380.0 torr and the vapor pressure of pure hexane (C6H14, MW = 86.17 g/mol) is p°H = 32.0 torr. What is the total pressure at 25oC when mixing equal grams of butane and hexane?
What is the vapor pressure  of a solution made by dissolving 79.3 g of glycerol (C3H8O3) in 123.8 g of water? The vapor pressure of water at 26  oC is 25.2 mmHg. A. 9.84 mmHg B. 15.4 mmHg C. 2.81 mmHg D. 22.4 mmHg E. 3.16 mmHg
(Hint: If you dont know where to start, try assuming you have 100g total of solution.) Consider two liquids A and B. The vapor pressure of pure A (molecular weight = 50 g/mol) is 225 torr at 25°C and the vapor pressure of pure B (molecular weight = 75 g/mol) is 90 torr at the same temperature. What is the total vapor pressure at 25°C of a solution that is 25% A amd 75% B by weight? 1. 76 torr 2. 225 torr 3. 335 torr 4. 203 torr 5. 135 torr 6. 191 torr 7. 108 torr 8. 115 torr 9. 124 torr    
The vapor pressure of pure water (H2O) at 30 °C is 40 torr. If salt (NaCl) is dissolved into a sample of water until the total vapor pressure of the mixture at 30 °C is 32 torr, what is the mol fraction of  salt? 1. 0.2 2. 0.5 3. 0.8 4. 0.65 5. 0.35
The van't Hoff factors are a function of the concentration and are often lower than the theoretical value. Would you expect a larger or smaller deviation from the theoretical value as a solution gets more concentrated? Explain.
Red blood cells contain Na+ ions, K+ ions, and water. If we place some red blood cells into a beaker full of pure water, what will happen to them? they will swell and burst they will wiggle around rapidly nothing they will shrivel and collapse
Explain why the lower vapor pressure for a solution containing a nonvolatile solute results in a higher boiling point and lower melting point compared to the pure solvent.
What are colligative properties?
Which solution has the highest boiling point?
The osmotic pressure of 0.013 M aqueous solution of CaCl2 is found to be 0.693 atm at 25 oC.Calculate the vant Hoff factor, i, for the solution.
You may wantto reference (Pages 608 - 608) Section 13.7 while completing this problemA solution of benzene (C6H6) and toluene (C7H8) is 26.0 % benzene by mass. At 25oC the vapor pressures of pure benzene and pure toluene are 94.2 and 28.4 torr, respectively.Assuming ideal behavior, calculate the vapor pressure of benzene in the mixture.
You may wantto reference (Pages 608 - 608) Section 13.7 while completing this problemA solution of benzene (C6H6) and toluene (C7H8) is 26.0 % benzene by mass. At 25oC the vapor pressures of pure benzene and pure toluene are 94.2 and 28.4 torr, respectively.Assuming ideal behavior, calculate the total pressure above the solution.
You may wantto reference (Pages 608 - 608) Section 13.7 while completing this problemA solution of benzene (C6H6) and toluene (C7H8) is 26.0 % benzene by mass. At 25oC the vapor pressures of pure benzene and pure toluene are 94.2 and 28.4 torr, respectively.Assuming ideal behavior, calculate the mass percent of benzene in the vapor.
You may wantto reference (Pages 608 - 608) Section 13.7 while completing this problemA solution of benzene (C6H6) and toluene (C7H8) is 26.0 % benzene by mass. At 25oC the vapor pressures of pure benzene and pure toluene are 94.2 and 28.4 torr, respectively.Assuming ideal behavior, calculate the vapor pressure of toluene in the mixture.
You may wantto reference (Pages 608 - 608) Section 13.7 while completing this problemA solution of benzene (C6H6) and toluene (C7H8) is 26.0 % benzene by mass. At 25oC the vapor pressures of pure benzene and pure toluene are 94.2 and 28.4 torr, respectively.Assuming ideal behavior, calculate the mass percent of toluene in the vapor.
What is the effect of a nonvolatile solute on the vapor pressure of a liquid? Why is the vapor pressure of a solution different from the vapor pressure of the pure liquid solvent?
You may wantto reference (Pages 608 - 608) Section 13.7 while completing this problemA solution of benzene (C6H6) and toluene (C7H8) is 26.0 % benzene by mass. At 25oC the vapor pressures of pure benzene and pure toluene are 94.2 and 28.4 torr, respectively.Why is the composition of the vapor different from the composition of the solution?
What is the effect on vapor pressure of a solution with particularly strong solute-solvent interactions? With particularly weak solute-solvent interactions?
A beaker contains 100.0 mL of pure water. A second beaker contains 100.0 mL of seawater. The two beakers are left side by side on a lab bench for one week. At the end of the week, the liquid level in both beakers has decreased. However, the level has decreased more in one of the beakers than in the other.Which one level has decreased more?
A solution of methanol and water has a mole fraction of water of 0.312 and a total vapor pressure of 211 torr at 39.9oC. The vapor pressures of pure methanol and pure water at this temperature are 256 torr and 55.3 torr, respectively.Is the solution ideal?
At 35 oC the vapor pressure of acetone, (CH3 )2 CO, is 361 torr, and that of chloroform, CHCl3, is 301 torr. Acetone and chloroform can form weak hydrogen bonds between one another; the chlorines on the carbon give the carbon a sufficient partial positive charge to enable this behavior: A solution composed of an equal number of moles of acetone and chloroform has a vapor pressure of 250 torr at 35 oC.What would be the vapor pressure of the solution if it exhibited ideal behavior?
The vapor pressure of pure water at 60oC is 149 torr. The vapor pressure of water over a solution at 60 oC containing equal numbers of moles of water and ethylene glycol (a nonvolatile solute) is 67 torr. Is the solution ideal according to Raoults law?
The following diagram shows the vapor pressure curves of a volatile solvent and a solution of that solvent containing a nonvolatile solute. Which line represents the solution?
Calculate the vapor pressure of water above a solution prepared by adding 23.0 g of lactose (C12 H22 O11 ) to 200.0 g of water at 338 K. (Vapor-pressure of water at 338 K 187.5 torr.)
Calculate the mass of propylene glycol (C3 H8 O2 ) that must be added to 0.350 kg of water to reduce the vapor pressure by 2.88 torr at 40 oC (PH2O at 40 C = 55.3).
At 63.5oC the vapor pressure of H2O is 175 torr, and that of ethanol (C2H5OH) is 400 torr. A solution is made by mixing equal masses of H2O and C2H5OH.Assuming ideal-solution behavior, what is the vapor pressure of the solution at 63.5oC?
Calculate the vapor pressure at 25 oC of an aqueous solution that is 5.55 % NaCl by mass.
An aqueous CaCl2 solution has a vapor pressure of 82.1 mmHg at 50 oC. The vapor pressure of pure water at this temperature is 92.6 mmHg.What is the concentration of CaCl2 in mass percent?
The vapor above an aqueous solution contains 19.1 mg water per liter at 25 oC.Assuming ideal behavior, what is the concentration of the solute within the solution in mole percent?
A solution of 75.0 g of benzene (C6H6) and 75.0 g of toluene (C7H8) has a total vapor pressure of 80.9 mmHg at 303 K. Another solution of 100.0 g benzene and 50.0 g toluene has a total vapor pressure of 93.9 mmHg at this temperature.Find the vapor pressure of pure toluene at 303 K.
Two beakers are placed in a sealed box at 25 oC. One beaker contains 35.0 mL of a 5.5×10−2 M aqueous solution of a nonvolatile nonelectrolyte. The other beaker contains 35.0 mL of a 4.0×10−2 M aqueous solution of NaCl. The water vapor from the two solutions reaches equilibrium.In which beaker does the solution level rise, and in which one does it fall?
Two beakers are placed in a sealed box at 25 oC. One beaker contains 35.0 mL of a 5.5×10−2 M aqueous solution of a nonvolatile nonelectrolyte. The other beaker contains 35.0 mL of a 4.0×10−2 M aqueous solution of NaCl. The water vapor from the two solutions reaches equilibrium.What is the volume in the beaker with the aqueous solution of NaCl when equilibrium is attained, assuming ideal behavior?
Two beakers are placed in a sealed box at 25 oC. One beaker contains 35.0 mL of a 5.5×10−2 M aqueous solution of a nonvolatile nonelectrolyte. The other beaker contains 35.0 mL of a 4.0×10−2 M aqueous solution of NaCl. The water vapor from the two solutions reaches equilibrium.What is the volume in the beaker with the aqueous solution of a nonvolatile nonelectrolyte when equilibrium is attained, assuming ideal behavior?
Consider two solutions, one formed by adding 10 g of glucose (C6 H12 O6 ) to 1 L of water and the other formed by adding 10 g of sucrose (C12 H22 O11 ) to 1 L of water.Calculate the vapor pressure for the first solution at 20 oC. (The vapor pressure of pure water at this temperature is 17.5 torr.)
Consider two solutions, one formed by adding 10 g of glucose (C6 H12 O6 ) to 1 L of water and the other formed by adding 10 g of sucrose (C12 H22 O11 ) to 1 L of water.Calculate the vapor pressure for the second solution at 20 oC. (The vapor pressure of pure water at this temperature is 17.5 torr.)
A solution contains 4.08 g of chloroform (CHCl3 ) and 9.29 g of acetone (CH3 COCH3 ). The vapor pressures at 35 oC of pure chloroform and pure acetone are 295 torr and 332 torr, respectively.Assuming ideal behavior, calculate the vapor pressure of chloroform.
A solution contains 4.08 g of chloroform (CHCl3 ) and 9.29 g of acetone (CH3 COCH3 ). The vapor pressures at 35 oC of pure chloroform and pure acetone are 295 torr and 332 torr, respectively.The experimentally measured total vapor pressure of the solution at 35 oC was 312 torr. Is the solution ideal?
A solution contains 4.08 g of chloroform (CHCl3 ) and 9.29 g of acetone (CH3 COCH3 ). The vapor pressures at 35 oC of pure chloroform and pure acetone are 295 torr and 332 torr, respectively.Assuming ideal behavior, calculate the total vapor pressure above the solution.
A solution contains 0.111 mol H2O and an unknown number of moles of sodium chloride. The vapor pressure of the solution at 30 oC is 25.7 torr. The vapor pressure of pure water at this temperature is 31.8 torr.Calculate the number of grams of sodium chloride in the solution. (Hint: Remember that sodium chloride is a strong electrolyte.)
The vapor pressure of carbon tetrachloride, CCl4, is 0.354 atm and the vapor pressure of chloroform, CHCl3, is 0.526 atm at 316 K. A solution is prepared from equal masses of these two compounds at this temperature.Calculate the mole fraction of the chloroform in the vapor above the solution.
The vapor pressure of carbon tetrachloride, CCl4, is 0.354 atm and the vapor pressure of chloroform, CHCl3, is 0.526 atm at 316 K. A solution is prepared from equal masses of these two compounds at this temperature.If the vapor above the original solution is condensed and isolated into a separate flask, what would the vapor pressure of chloroform be above this new solution?
The normal boiling point of ethanol, CH3CH2OH, is 78.4 C. When 8.65 g of a soluble nonelectrolyte is dissolved in 100.0 g of ethanol at that temperature, the vapor pressure of the solution is 7.40 102 torr. What is the molar mass of the solute?
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 oC.What is the molar mass of lysozyme?
The osmotic pressure of a solution containing 2.10 g of an unknown compound dissolved in 175.0 mL of solution at 25 oC is 1.93 atm . The combustion of 24.02 g of the unknown compound produced 28.16 g CO2 and 8.640 g H2O.What is the molecular formula of the compound (which contains only carbon, hydrogen, and oxygen)?
A metal, M, of atomic weight 96 reacts with fluorine to form a salt that can be represented as MFx. In order to determine x and therefore the formula of the salt, a boiling point elevation experiment is performed. A 9.18-g sample of the salt is dissolved in 100.0 g of water and the boiling point of the solution is found to be 374.38 K.Find the formula of the salt. Assume complete dissociation of the salt in solution.
Carbon disulfide (CS2 ) boils at 46.30 oC and has a density of 1.261 g/mL.When 5.40 g of a nondissociating unknown is dissolved in 50.0 mL of CS2, the solution boils at 47.08 oC. What is the molecular weight of the unknown?
A lithium salt used in lubricating grease has the formula LiCn H2n + 1 O2. The salt is soluble in water to the extent of 0.036 g per 100 g of water at 25 oC. The osmotic pressure of this solution is found to be 57.1 torr.Assuming that molality and molarity in such a dilute solution are the same and that the lithium salt is completely dissociated in the solution, determine an appropriate value of n in the formula for the salt.
What is osmosis? What is osmotic pressure?
What is the osmotic pressure of a solution formed by dissolving 44.3 mg of aspirin (C9 H8 O4 ) in 0.358 L of water at 25 oC?
Is the osmotic pressure of a 0.10 M solution of NaCl greater than, less than, or equal to that of a 0.10 M solution of KBr?
Does a 0.10 m aqueous solution of NaCl have a higher boiling point, a lower boiling pointpoint, or the same boiling point as a 0.10 m aqueous solution of C6H12O6?
Explain why drinking seawater results in dehydration.
Which term describes the energy change associated with molecules that have some movement past each other to molecules that have no interactions with other molecules? A. ΔHvap            B. ΔH fus            C. ΔH cond            D. C p(gas)            E. C p(liquid)
75.225 g of an unknown compound is dissolved in 455.00 g of H 2O. A scientist measures that the solution now freezes at -9.26°C. Assuming that the compound is NOT ionic, what is the molecular weight of the compound kf = 1.86°Cm-1.
For an aqueous solution of HF, determine the van't Hoff factor assuming:i) 0% ionizationii) 100% ionization
If all of the following solutions were held at 25.00 oC and the osmotic pressure were carefully monitored, which of the solutions would have the highest osmotic pressure?A. 1.0 M glucose, C6H12O6B. 0.35 M CaCl2C. 0.25 M Na2SO4D. 0.30 M AlCl3E. 0.52 M KCl
A and B are volatile miscible liquids. The partial pressures of A and B and the total pressure above a solution of A and B are given in the diagram below as a function of XA, the mole fraction of A, and at a temperature T = 40.0 °C. Based on the diagram answer the following questions. a) Do A and B form an ideal liquid solution (yes or no, and a brief justification for your answer)? b) What is pB°, the vapor pressure of pure B, at T = 40.0 °C?
The osmotic pressure of a solution containing 2.46 mg of an unknown protein in 50.0 mL of solution is 1.66 atm at 25 oC? Find the molar mass of the unknown protein. a. 0.766 g/molb. 0.587 g/molc. 0.725 g/mold. 0.487 g/mole. 0.357 g/mol 
2.09 g of copper II nitrate (Cu(NO 3)2, MW = 187.56 g/mol) is dissolved in water, to form a solution with final volume V = 250.0 mL. What is the osmotic pressure of the solution relative to pure water? Assume T = 25.0 °C in your calculations, and give your final answer in units of atm.
Assume you add 10 mL of water in an evacuated and sealed container held at 25°C. Which of the following would decrease the vapor pressure?I) adding a nonvolatile soluteII) halving the size of the containerIII) removing some liquid1. I and II2. II only3. I and III4. I, II, and III5. I only6. III only7. II and III
Identify the solute with the highest van't Hoff factor.A. Non-electrolyteB. NaClC. MgSO4D. MgCl2E. FeCl3
At 25°C the vapor pressure of pure hexane (C 6H14) is 0.198atm, while that of pure heptane (c7H16) is 0.060 atm.Calculate the vapor pressure of a mixture of 17.2 g of hexane and 25.0 g of heptane at 25°C, assuming hexane and heptane form an ideal solution. (a) 0.0546 atm(b) 0.121 atm(c) 0.129 atm(d) 0.137(e) none of these
The boiling point of an aqueous 1.83 m salt solution is 102.5°C. Determine the value of the van't Hoff factor for this solute if the Kb for water is 0.512°C/m.A. 3.0B. 3.6C. 1.8D. 2.7E. 2.3
1.53 x 10‐2 M solutions of CaCl 2 and urea at 25°C have osmotic pressures of 0.926 and 0.375 atm, respectively. Calculatle the van’t Hoff factor for the CaCl2 solution.A) 1B) 2C) 2.46D) 2.76E) 3 
Arrange the following aqueous solutions in order of decreasing freezing point (left to right):I) 0.1 m Na3PO4,II) 0.1 m NaCl,III) 0.1 m MgCl2,IV) 0.1 m C6H12O6,V) 0.1 m SnCl4Highest FP            Lowest FPA) I < II < III < IV < VB) V < IV < III < II < IC) I < V < II < III < IVD) IV < II < III < I < VE) IV < I < III < II < V
The osmotic pressure of a 0.010 M potassium iodide (KI) solution at 25 °C is 0.465 atm. Calculate the van’t Hoff factor for KI at this concentration.
A mixture of ethanol and 1‐propanol behaves ideally at 36°C and is in equilibrium with its vapor. If the mole fraction of ethanol in the solution is 0.67, calculate its mole fraction in the vapor phase at this temperature. (The vapor pressures of pure ethanol and 1‐propanol at 36°C are 108 and 40.0 mmg Hg, respectively.)A) 0.15B) 0.33C) 0.67D) 0.73E) 0.84
The vapor pressure of pure ethanol (C 2H5OH) is 44 mmHg and the vapor pressure of pure methanol (CH3OH) at the same temperature is 94 mmHg. A mixture of 48 g of methanol and 69 g of ethanol forms an ideal solution. Calculate the combined vapor pressure of the resulting solution.A) 1 atmB) 138 mmHgC) 69 mmHgD) 47 mmHgE) 22 mmHg
Lauryl alcohol, a component of coconut oil, is used to make detergents. A solution of 5.00 g of lauryl alcohol in 0.100 kg of benzene freezes at 4.1°C. What is the molar mass of lauryl alcohol? Kf (benzene) = 5.12°C/m; Tf (benzene) = 5.50°C.a) 270 g/molb) 13.7 g/molc) 62.4 g/mold) 46.5 g/mole) 183 g/mol
In a(n) _____ solution, red blood cells _____.A) isosmotic, have a normal shape.B) hyperosmotic, have a normal shapeC) isosmotic, lose water and shrivelD) isosmotic, swell and may burstE) none of the above
Rank the following solutions from lowest to highest vapor pressure. To rank items as equivalent, overlap themi) 20 g. of glucose C 6H12O6 in 100ml H2Oii) 10 g. of protassium acetate KC 2H3O2 in 100ml H2Oiii) 20 g. of sucrose C12H22O11 in 100ml H2O
Which of the following solutions will have the lowest freezing point? a. 0.2M KBrb. 0.4M HNO3c. 0.6M ethanol C2H5OHd. 0.2M K2SO4
The vapor pressures (in torr) of solid and liquid chlorine are given by
A solution of 2.50 g of a nonelectrolyte is dissolved in 10.0 g of water and the solution freezes at -3.720°C. What is the molecular weight of the nonelectrolyte?Kf(H2O) = 1.860°C/ma) 50.0 g/molb) 75.0 g/molc) 100 g/mold) 125 g/mole) 150 g/mol   
Given the Kf of water is 1.86° C/m, which of the following aqueous solutions has the lowest freezing point?a) 0.18 m KClb) 0.15 m Na 2SO4c) 0.12 m Ca(NO3)2d) pure watere) 0.20 m C2H6O2 (ethylene glycol)
Which of the following choices shows the correct arrangement of the given aqueous solutions in order of lowest freezing point to highest freezing point?   I) 0.10 m HBrII) 0.35 m KOHIII) 0.20 m MgCl2 IV) 0.15 m HF? a) IV, I, III, IIb) I, II, III, IVc) III, I, IV, IId) II, III, IV, Ie) some other order
A semipermeable membrane is placed between the following solutions. Which solution will decrease in volume? a. Solution A: 1.31% (m/v) starch b. Solution B: 7.48% (m/v) starch
A semipermeable membrane is placed between the following solutions. Which solution will increase in volume? a. Solution A: 6.75% NaCl b. Solution B: 11.7% NaCl
An aqueous solution at 25°C contains 35 grams of a non-ionizing solute with MW = 83.1 g/mol. The total mass of the solution is 215 grams. The vapor pressure of pure water at 25°C is 23.76 torr. What is the vapor pressure of the solution?A. 23.36 torrB. 23.76 torrC. 0.96 torrD. 2.96 torrE. 22.8 torr
Arrange the following aqueous solutions in order of increasing boiling points: 0.050 m Mg(NO3)2; 0.10m ethenol; 0.090m NaCla. ethanol <Mg(NO3)2 < NaClb. Mg(NO3)2 < ethanol < NaClc. Mg(NO3)2 <NaCl < ethanold. NaCl <ethanol <Mg(NO3)2e. ethanol <NaCl <Mg(NO3)2
Using freezing point depression to find molecular weightMass of Lauric Acid (g)                                                                     8.003Mass of benzoic Acid (g)                                                                   1.010Freezing temperature of pure lauric acid (C°)                                   43.84Freezing temperature of the benzoic acid-lauric acid mixture (C°)   39.05a. Calculate molality (m), in mol/kg, using the formula Δt = Kf  * m. The Kf value for lauric acid is 3.9°C•kg/mol. b. Calculate moles of benzoic acid solute, using the molality and the mass (in kg) of lauric acid solvent.  c. Calculate the experimental molecular weight of benzoic acid, in g/mol.  d. Determine the accepted molecular weight of benzoic acid from its formula, C 6H5COOH. e. Calculate the percent discrepancy between the experimental and accepted values.   
Which of the following is not a colligative property?a. osmotic pressureb. Henry’s Lawc. vapor pressure loweringd. freezing point depressione. boiling point elevation
A 0.25 gram sample of an unknown compound (a nonelectrolyte where i = 1) is dissolved in 225 mL of water. This solution is found to have an osmotic pressure of 342 torr at a temperature of 28°C. What is the molar mass of the unknown compound?
Acetone, CH3COCH3 (58 g/mol), and ethyl acetate, C2H5COOCH3 (88 g/mol), are common organic solvents. At 30°C, the vapor pressure of acetone is 285 torr, and the vapor pressure of ethyl acetate is 120 torr. What is the vapor pressure at 30°C of a solution prepared by dissolving 11 g of ethyl acetate into 29 g of acetone?
 When a nonvolatile solute is added to a volatile solvent, the solution vapor pressure, the boiling point ___________________ the freezing point__________ and the osmotic pressure across a semi permeable membrane _________________________. a) decreases, increases. decreases, increasesb) increases, increases, decreases, increasesc) increases, decreases, increases, decreasesd) decreases, decreases, increases, decreasese) decreases; increases. decreases. decreases
Calculate the mole fraction of methanol in the vapor phase at 63.° C for an ideal solution containing 25.0 g of pure methanol (CH3OH, 32.0 g/mol) and 75.0 g of pure ethanol (CH3CH2OH, 46.1 g/mol)). The vapor pressure of methanol and ethanol at 63.5°C is 717.2 mmHg and 400.0 mmHg, respectively. a) 0.463b) 0.642c) 0.0925d) 0.163e) none of the above
Colligative properties are similar in that they all ________a. lower the activation energy of the solventb. have no effect on the properties of solutionc. describe colloidsd. are due to solvent-solvent chemical interactionse. depend on the number of solute particles in solution
A solution is made by dissolving 40.0 grams of magnesium phosphate (MM = 262.87) in 500 grams of water. The observed boiling point of the solution is 100.50°C, what is the observed Van’t Hoff factor for magnesium phosphate in this solution? The Kb for water is 0.512°C/m.A. 0.025B. 1.6C. 3.2D. 4.8E. 5.0
A 0.126 M ionic solution has an osmotic pressure of 8.3 atm at 28 oC. Calculate the van't Hoff factor (i) for this solution.
Which of the following is true for all colligative properties?a) The measurement must be made at constant temperature for all colligative propertiesb) The measurement must be made at constant pressure for all colligative propertiesc) The measurement must be made in a closed containerd) It is the number of particles that is important and not their typee) The intermolecular forces are responsible for the colligative properties
Rank the following aqueous solutions in order of decreasing boiling point.A. 0.020 m NaBr > 0.012 m KCl > 0.005 m SrCl2 > 0.012 m sucroseB. 0.020 m NaBr > 0.005 m SrCl2 > 0.012 m KCl = 0.012 m sucroseC. 0.005 m SrCl2 > 0.012 m KCl > = 0.012 m sucrose > 0.020 m NaBrD. 0.012 m sucrose > 0.012 m KCl > 0.005 m SrCl2 > 0.020 m NaBr
Which of the following solutions will have the highest electrical conductivity?a. 0.10 M Klb. 0.050 M (NH4)2CO3c. 0.10 M KFd. 0.045 M Al2(SO4)3e. 0.10 M KBr
Which of the following aqueous solutions has the lowest freezing point?a. 0.18 m KClb. 0.15 m Na 2SO4c. 0.12 m Ca(NO3)2d. pure watere. 0.20 m C2H6O2 (ethylene glycol)
A 1.00 g sample of Cr(NH 3)4Cl4 (MW = 261.84 g/mol) is dissolved in 25.0 g of water and the freezing point of the solution is -0.85°C. How many io