Solved: Propose structures for alcohols that have the

Which solvent, water or carbon tetrachloride, would you choose to dissolve each of the following? a. KrF2 e. MgF2 b. SF2 f. CH2O c. SO2 g. CH2PCH2 d. CO2

Which solvent, water or hexane (C6H14), would you choose to dissolve each of the following? a. Cu(NO3)2 d. CH3(CH2)16CH2OH b. CS2 e. HCl c. CH3OH f. C6H

For each of the following pairs, predict which substance would be more soluble in water. NH3 PH3 or

Which ion in each of the following pairs would you expect to be more strongly hydrated? Why? a. Na1 or Mg21 d. F2 or Br2 b. Mg21 or Be21 e. Cl2 or ClO4 2 c. Fe21 or Fe31 f. ClO4 2 or SO4 2

Rationalize the trend in water solubility for the following simple alcohols: Alcohol Solubility (g/100 g H2O at 208C) Methanol, CH3OH Soluble in all proportions Ethanol, CH3CH2OH Soluble in all proportions Propanol, CH3CH2CH2OH Soluble in all proportions Butanol, CH3(CH2)2CH2OH 8.14 Pentanol, CH3(CH2)3CH2OH 2.64 Hexanol, CH3(CH2)4CH2OH 0.59 Heptanol, CH3(CH2)5CH2OH 0.09

In flushing and cleaning columns used in liquid chromatography to remove adsorbed contaminants, a series of solvents is used. Hexane (C6H14), chloroform (CHCl3), methanol (CH3OH), and water are passed through the column in that order. Rationalize the order in terms of intermolecular forces and the mutual solubility (miscibility) of the solvents.

The solubility of nitrogen in water is 8.21 3 1024 mol/L at 08C when the N2 pressure above water is 0.790 atm. Calculate the Henrys law constant for N2 in units of mol/L ? atm for Henrys law in the form C 5 kP, where C is the gas concentration in mol/L. Calculate the solubility of N2 in water when the partial pressure of nitrogen above water is 1.10 atm at 08C.

Calculate the solubility of O2 in water at a partial pressure of O2 of 120 torr at 258C. The Henrys law constant for O2 is 1.3 3 1023 mol/L ? atm for Henrys law in the form C 5 kP, where C is the gas concentration (mol/L).

Glycerin, C3H8O3, is a nonvolatile liquid. What is the vapor pressure of a solution made by adding 164 g glycerin to 338 mL H2O at 39.88C? The vapor pressure of pure water at 39.88C is 54.74 torr and its density is 0.992 g/cm3 .

The vapor pressure of a solution containing 53.6 g glycerin (C3H8O3) in 133.7 g ethanol (C2H5OH) is 113 torr at 408C. Calculate the vapor pressure of pure ethanol at 408C assuming that glycerin is a nonvolatile, nonelectrolyte solute in ethanol.

The normal boiling point of diethyl ether is 34.58C. A solution containing a nonvolatile solute dissolved in diethyl ether has a vapor pressure of 698 torr at 34.58C. What is the mole fraction of diethyl ether in this solution?

At a certain temperature, the vapor pressure of pure benzene (C6H6) is 0.930 atm. A solution was prepared by dissolving 10.0 g of a nondissociating, nonvolatile solute in 78.11 g of benzene at that temperature. The vapor pressure of the solution was found to be 0.900 atm. Assuming the solution behaves ideally, determine the molar mass of the solute

A solution is made by dissolving 25.8 g urea (CH4N2O), a nonelectrolyte, in 275 g water. Calculate the vapor pressures of this solution at 258C and 458C. (The vapor pressure of pure water is 23.8 torr at 258C and 71.9 torr at 458C.)

A solution of sodium chloride in water has a vapor pressure of 19.6 torr at 258C. What is the mole fraction of solute particles in this solution? What would be the vapor pressure of this solution at 458C? The vapor pressure of pure water is 23.8 torr at 258C and 71.9 torr at 458C, and assume sodium chloride exists as Na1 and Cl2 ions in solution.

Pentane (C5H12) and hexane (C6H14) form an ideal solution. At 258C the vapor pressures of pentane and hexane are 511 and 150. torr, respectively. A solution is prepared by mixing 25 mL pentane (density, 0.63 g/mL) with 45 mL hexane (density, 0.66 g/mL). a. What is the vapor pressure of the resulting solution? b. What is the composition by mole fraction of pentane in the vapor that is in equilibrium with this solution?

A solution is prepared by mixing 0.0300 mole of CH2Cl2 and 0.0500 mole of CH2Br2 at 258C. Assuming the solution is ideal, calculate the composition of the vapor (in terms of mole fractions) at 258C. At 258C, the vapor pressures of pure CH2Cl2 and pure CH2Br2 are 133 and 11.4 torr, respectively.

What is the composition of a methanol (CH3OH)propanol (CH3CH2CH2OH) solution that has a vapor pressure of 174 torr at 408C? At 408C, the vapor pressures of pure methanol and pure propanol are 303 and 44.6 torr, respectively. Assume the solution is ideal

Benzene and toluene form an ideal solution. Consider a solution of benzene and toluene prepared at 258C. Assuming the mole fractions of benzene and toluene in the vapor phase are equal, calculate the composition of the solution. At 258C the vapor pressures of benzene and toluene are 95 and 28 torr, respectively

Which of the following will have the lowest total vapor pressure at 258C? a. pure water (vapor pressure 5 23.8 torr at 258C) b. a solution of glucose in water with xC6H12O6 5 0.01 c. a solution of sodium chloride in water with xNaCl 5 0.01 d. a solution of methanol in water with xCH3OH 5 0.2 (Consider the vapor pressure of both methanol [143 torr at 258C] and water.)

Which of the choices in Exercise 61 has the highest vapor pressure?

Match the vapor pressure diagrams with the solutesolvent combinations and explain your answers. a. b. c. Vapor pressure Vapor pressure of solution Vapor pressure of solution Vapor pressure of solution Partial pressure B Partial pressure A B A B A B A H H H H H H O C C C H H O H H O H H O H H H H H H C O C H H H H H H H H H H H H H H C C C C C C H H H H H H H H H H H H H H H H C C C C C C C H H H H H H H H H H H H H H H H C C C C C C C a. c. d. b. and and and and

The vapor pressures of several solutions of waterpropanol (CH3CH2CH2OH) were determined at various compositions, with the following data collected at 458C: xH2O Vapor Pressure (torr) 0 74.0 0.15 77.3 0.37 80.2 0.54 81.6 0.69 80.6 0.83 78.2 1.00 71.9 a. Are solutions of water and propanol ideal? Explain. b. Predict the sign of DHsoln for waterpropanol solutions.c. Are the interactive forces between propanol and water molecules weaker than, stronger than, or equal to the interactive forces between the pure substances? Explain. d. Which of the solutions in the data would have the lowest normal boiling point?

A solution is prepared by dissolving 27.0 g urea, (NH2)2CO, in 150.0 g water. Calculate the boiling point of the solution. Urea is a nonelectrolyte

A 2.00-g sample of a large biomolecule was dissolved in 15.0 g carbon tetrachloride. The boiling point of this solution was determined to be 77.858C. Calculate the molar mass of the biomolecule. For carbon tetrachloride, the boiling-point constant is 5.038C ? kg/mol, and the boiling point of pure carbon tetrachloride is 76.508C.

What mass of glycerin (C3H8O3), a nonelectrolyte, must be dissolved in 200.0 g water to give a solution with a freezing point of 21.508C?

The freezing point of t-butanol is 25.508C and Kf is 9.18C ? kg/ mol. Usually t-butanol absorbs water on exposure to air. If the freezing point of a 10.0-g sample of t-butanol is 24.598C, how many grams of water are present in the sample?

Calculate the freezing point and boiling point of an antifreeze solution that is 50.0% by mass of ethylene glycol (HOCH2CH2OH) in water. Ethylene glycol is a nonelectrolyte.

What volume of ethylene glycol (C2H6O2), a nonelectrolyte, must be added to 15.0 L water to produce an antifreeze solution with a freezing point of 225.08C? What is the boiling point of this solution? (The density of ethylene glycol is 1.11 g/cm3 , and the density of water is 1.00 g/cm3 .)

Reserpine is a natural product isolated from the roots of the shrub Rauwolfia serpentina. It was first synthesized in 1956 by Nobel Prize winner R. B. Woodward. It is used as a tranquilizer and sedative. When 1.00 g reserpine is dissolved in 25.0 g camphor, the freezing-point depression is 2.63C (Kf for camphor is 40.8C ? kg/mol). Calculate the molality of the solution and the molar mass of reserpine.

A solution contains 3.75 g of a nonvolatile pure hydrocarbon in 95 g acetone. The boiling points of pure acetone and the solution are 55.958C and 56.508C, respectively. The molal boiling-point constant of acetone is 1.718C ? kg/mol. What is the molar mass of the hydrocarbon?

a. Calculate the freezing-point depression and osmotic pressure at 258C of an aqueous solution containing 1.0 g/L of a protein (molar mass 5 9.0 3 104 g/mol) if the density of the solution is 1.0 g/cm3 . b. Considering your answer to part a, which colligative property, freezing-point depression or osmotic pressure, would be better used to determine the molar masses of large molecules? Explain

Erythrocytes are red blood cells containing hemoglobin. In a saline solution they shrivel when the salt concentration is high and swell when the salt concentration is low. In a 258C aqueous solution of NaCl, whose freezing point is 20.4068C, erythrocytes neither swell nor shrink. If we want to calculate the osmotic pressure of the solution inside the erythrocytes under these conditions, what do we need to assume? Why? Estimate how good (or poor) of an assumption this is. Make this assumption and calculate the osmotic pressure of the solution inside the erythrocytes.

An aqueous solution of 10.00 g of catalase, an enzyme found in the liver, has a volume of 1.00 L at 278C. The solutions osmotic pressure at 278C is found to be 0.745 torr. Calculate the molar mass of catalase

A 0.15-g sample of a purified protein is dissolved in water to give 2.0 mL of solution. The osmotic pressure is found to be 18.6 torr at 258C. Calculate the proteins molar mass.

How would you prepare 1.0 L of an aqueous solution of sucrose (C12H22O11) having an osmotic pressure of 15 atm at a temperature of 228C? Sucrose is a nonelectrolyte.

How would you prepare 1.0 L of an aqueous solution of sodium chloride having an osmotic pressure of 15 atm at 228C? Assume sodium chloride exists as Na1 and Cl2 ions in solution.

Consider the following solutions: 0.010 m Na3PO4 in water 0.020 m CaBr2 in water 0.020 m KCl in water 0.020 m HF in water (HF is a weak acid.) a. Assuming complete dissociation of the soluble salts, which solution(s) would have the same boiling point as 0.040 m C6H12O6 in water? C6H12O6 is a nonelectrolyte. b. Which solution would have the highest vapor pressure at 288C? c. Which solution would have the largest freezing-point depression?

From the following: pure water solution of C12H22O11 (m 5 0.01) in water solution of NaCl (m 5 0.01) in water solution of CaCl2 (m 5 0.01) in water Choose the one with the a. highest freezing point. b. lowest freezing point. c. highest boiling point. d. lowest boiling point. e. highest osmotic pressure

Calculate the freezing point and the boiling point of each of the following solutions. (Assume complete dissociation.) a. 5.0 g NaCl in 25 g H2O b. 2.0 g Al(NO3)3 in 15 g H2O

A water desalination plant is set up near a salt marsh containing water that is 0.10 M NaCl. Calculate the minimum pressure that must be applied at 20.8C to purify the water by reverse osmosis. Assume NaCl is completely dissociated.

Determine the vant Hoff factor for the following ionic solute dissolved in water.

Consider the following representations of an ionic solute in water. Which flask contains MgSO4, and which flask contains NaCl? How can you tell?

Calculate the freezing point and the boiling point of each of the following aqueous solutions. (Assume complete dissociation.) a. 0.050 m MgCl2 b. 0.050 m FeCl3

Calculate the freezing point and the boiling point of each of the following solutions using the observed vant Hoff factors in Table 11.6. a. 0.050 m MgCl2 b. 0.050 m FeCl3

Use the following data for three aqueous solutions of CaCl2 to calculate the apparent value of the vant Hoff factor. Molality Freezing-Point Depression (8C) 0.0225 0.110 0.0910 0.440 0.278 1.330

The freezing-point depression of a 0.091-m solution of CsCl is 0.3208C. The freezing-point depression of a 0.091-m solution of CaCl2 is 0.4408C. In which solution does ion association appear to be greater? Explain

In the winter of 1994, record low temperatures were registered throughout the United States. For example, in Champaign, Illinois, a record low of 2298F was registered. At this temperature can salting icy roads with CaCl2 be effective in melting the ice? a. Assume i 5 3.00 for CaCl2. b. Assume the average value of i from Exercise 87. (The solubility of CaCl2 in cold water is 74.5 g per 100.0 g water.)

A 0.500-g sample of a compound is dissolved in enough water to form 100.0 mL of solution. This solution has an osmotic pressure of 2.50 atm at 258C. If each molecule of the solute dissociates into two particles (in this solvent), what is the molar mass of this solute?

The solubility of benzoic acid (HC7H5O2), C O O H is 0.34 g/100 mL in water at 258C and is 10.0 g/100 mL in benzene (C6H6) at 258C. Rationalize this solubility behavior. (Hint: Benzoic acid forms a dimer in benzene.) Would benzoic acid be more or less soluble in a 0.1-M NaOH solution than it is in water? Explain

Given the following electrostatic potential diagrams, comment on the expected solubility of CH4 in water and NH3 in water. H H O H H N H H H H H C

In a coffee-cup calorimeter, 1.60 g NH4NO3 was mixed with 75.0 g water at an initial temperature 25.008C. After dissolution of the salt, the final temperature of the calorimeter contents was 23.348C. a. Assuming the solution has a heat capacity of 4.18 J/g ? 8C, and assuming no heat loss to the calorimeter, calculate the enthalpy of solution (DHsoln) for the dissolution of NH4NO3 in units of kJ/mol. b. If the enthalpy of hydration for NH4NO3 is 2630. kJ/mol, calculate the lattice energy of NH4NO3.

In Exercise 96 in Chapter 5, the pressure of CO2 in a bottle of sparkling wine was calculated assuming that the CO2 was insoluble in water. This was a bad assumption. Redo this problem by assuming that CO2 obeys Henrys law. Use the data given in that problem to calculate the partial pressure of CO2 in the gas phase and the solubility of CO2 in the wine at 258C. The Henrys law constant for CO2 is 3.1 3 1022 mol/L ? atm at 258C with Henrys law in the form C 5 kP, where C is the concentration of the gas in mol/L.

Explain the following on the basis of the behavior of atoms and/or ions. a. Cooking with water is faster in a pressure cooker than in an open pan. b. Salt is used on icy roads. c. Melted sea ice from the Arctic Ocean produces fresh water. d. CO2(s) (dry ice) does not have a normal boiling point under normal atmospheric conditions, even though CO2 is a liquid in fire extinguishers. e. Adding a solute to a solvent extends the liquid phase over a larger temperature range.

The term proof is defined as twice the percent by volume of pure ethanol in solution. Thus, a solution that is 95% (by volume) ethanol is 190 proof. What is the molarity of ethanol in a 92 proof ethanolwater solution? Assume the density of ethanol, C2H5OH, is 0.79 g/cm3 and the density of water is 1.0 g/cm3

At 258C, the vapor in equilibrium with a solution containing carbon disulfide and acetonitrile has a total pressure of 263 torr and is 85.5 mole percent carbon disulfide. What is the mole fraction of carbon disulfide in the solution? At 258C, the vapor pressure of carbon disulfide is 375 torr. Assume the solution and vapor exhibit ideal behavior

For each of the following solutesolvent combinations, state the sign and relative magnitudes for DH1, DH2, DH3, and DHsoln (as defined in Fig. 11.1 of the text). Explain your answers. H H H H H H O C C C H H O H H O H H O H H H H H H C O C H H H H H H H H H H H H H H C C C C C C H H H H H H H H H H H H H H H H C C C C C C C H H H H H H H H H H H H H H H H C C C C C C C a. c. d. b. and and and

A solution is made by mixing 50.0 g acetone (CH3COCH3) and 50.0 g methanol (CH3OH). What is the vapor pressure of this solution at 258C? What is the composition of the vapor expressed as a mole fraction? Assume ideal solution and gas behavior. (At 258C the vapor pressures of pure acetone and pure methanol are 271 and 143 torr, respectively.) The actual vapor pressure of this solution is 161 torr. Explain any discrepancies.

If the fluid inside a tree is about 0.1 M more concentrated in solute than the groundwater that bathes the roots, how high will a column of fluid rise in the tree at 258C? Assume that the density of the fluid is 1.0 g/cm3 . (The density of mercury is 13.6 g/cm3 .)

Thyroxine, an important hormone that controls the rate of metabolism in the body, can be isolated from the thyroid gland. When 0.455 g thyroxine is dissolved in 10.0 g benzene, the freezing point of the solution is depressed by 0.3008C. What is the molar mass of thyroxine? See Table 11.5.

If the human eye has an osmotic pressure of 8.00 atm at 258C, what concentration of solute particles in water will provide an isotonic eyedrop solution (a solution with equal osmotic pressure)?

An unknown compound contains only carbon, hydrogen, and oxygen. Combustion analysis of the compound gives mass percents of 31.57% C and 5.30% H. The molar mass is determined by measuring the freezing-point depression of an aqueous solution. A freezing point of 25.208C is recorded for a solution made by dissolving 10.56 g of the compound in 25.0 g water. Determine the empirical formula, molar mass, and molecular formula of the compound. Assume that the compound is a nonelectrolyte.

Consider the following: Semipermeable membrane Pure solvent Solution What would happen to the level of liquid in the two arms if the semipermeable membrane separating the two liquids were permeable to a. H2O (the solvent) only? b. H2O and solute?

Consider an aqueous solution containing sodium chloride that has a density of 1.01 g/mL. Assume the solution behaves ideally. The freezing point of this solution at 1.0 atm is 21.288C. Calculate the percent composition of this solution (by mass).

What stabilizes a colloidal suspension? Explain why adding heat or adding an electrolyte can cause the suspended particles to settle out.

The freezing point of an aqueous solution is 22.798C. a. Determine the boiling point of this solution. b. Determine the vapor pressure (in mm Hg) of this solution at 258C (the vapor pressure of pure water at 258C is 23.76 mm Hg). c. Explain any assumptions you make in solving parts a and b

Specifications for lactated Ringers solution, which is used for intravenous (IV) injections, are as follows to reach 100. mL of solution: 285315 mg Na1 14.117.3 mg K1 4.96.0 mg Ca21 368408 mg Cl2 231261 mg lactate, C3H5O3 2 a. Specify the amount of NaCl, KCl, CaCl2 ? 2H2O, and NaC3H5O3 needed to prepare 100. mL lactated Ringers solution. b. What is the range of the osmotic pressure of the solution at 378C, given the preceding specifications?

Patients undergoing an upper gastrointestinal tract laboratory test are typically given an X-ray contrast agent that aids with the radiologic imaging of the anatomy. One such contrast agent is sodium diatrizoate, a nonvolatile water-soluble compound. A 0.378-m solution is prepared by dissolving 38.4 g sodium diatrizoate (NaDTZ) in 1.60 3 102 mL water at 31.28C (the density of water at 31.28C is 0.995 g/cm3). What is the molar mass of sodium diatrizoate? What is the vapor pressure of this solution if the vapor pressure of pure water at 31.28C is 34.1 torr?

A solution is prepared by dissolving 52.3 g cesium chloride in 60.0 g water. The volume of the solution is 63.3 mL. Calculate the mass percent, molarity, molality, and mole fraction of the CsCl solution

The lattice energy of NaCl is 2786 kJ/mol, and the enthalpy of hydration of 1 mole of gaseous Na1 and 1 mole of gaseous Cl2 ions is 2783 kJ/mol. Calculate the enthalpy of solution per mole of solid NaCl.

For each of the following pairs, predict which substance is more soluble in water. a. CH3NH2 or NH3 b. CH3CN or CH3OCH3 c. CH3CH2OH or CH3CH2CH3 d. CH3OH or CH3CH2OH e. (CH3)3CCH2OH or CH3(CH2)6OH f. CH3OCH3 or CH3CO2H

The normal boiling point of methanol is 64.78C. A solution containing a nonvolatile solute dissolved in methanol has a vapor pressure of 556.0 torr at 64.78C. What is the mole fraction of methanol in this solution?

A solution is prepared by mixing 1.000 mole of methanol (CH3OH) and 3.18 moles of propanol (CH3CH2CH2OH). What is the composition of the vapor (in mole fractions) at 408C? At 408C, the vapor pressure of pure methanol is 303 torr, and the vapor pressure of pure propanol is 44.6 torr.

The molar mass of a nonelectrolyte is 58.0 g/mol. Determine the boiling point of a solution containing 35.0 g of this compound and 600.0 g of water. The barometric pressure during Unless otherwise noted, all art on this page is Cengage Learning 2014. 550 Chapter 11 Properties of Solutions 11097_Ch11_0510-0551.indd 550 10/1/12 3:00 PM temperature of the solution. The vapor at equilibrium above the solution has double the mole fraction of substance A that the solution does. What is the mole fraction of liquid A in the solution? 129. In some regions of the southwest United States, the water is very hard. For example, in Las Cruces, New Mexico, the tap water contains about 560 mg of dissolved solids per milliliter. Reverse osmosis units are marketed in this area to soften water. A typical unit exerts a pressure of 8.0 atm and can produce 45 L water per day. a. Assuming all of the dissolved solids are MgCO3 and assuming a temperature of 278C, what total volume of water must be processed to produce 45 L pure water? b. Would the same system work for purifying seawater? (Assume seawater is 0.60 M NaCl.) Integrative Problems These problems require the integration of multiple concepts to find the solutions. 130. Creatinine, C4H7N3O, is a by-product of muscle metabolism, and creatinine levels in the body are known to be a fairly reliable indicator of kidney function. The normal level of creatinine in the blood for adults is approximately 1.0 mg per deciliter (dL) of blood. If the density of blood is 1.025 g/mL, calculate the molality of a normal creatinine level in a 10.0-mL blood sample. What is the osmotic pressure of this solution at 25.08C? 131. An aqueous solution containing 0.250 mole of Q, a strong electrolyte, in 5.00 3 102 g water freezes at 22.798C. What is the vant Hoff factor for Q? The molal freezing-point depression constant for water is 1.868C ? kg/mol. What is the formula of Q if it is 38.68% chlorine by mass and there are twice as many anions as cations in one formula unit of Q? 132. Anthraquinone contains only carbon, hydrogen, and oxygen. When 4.80 mg anthraquinone is burned, 14.2 mg CO2 and 1.65 mg H2O are produced. The freezing point of camphor is lowered by 22.38C when 1.32 g anthraquinone is dissolved in 11.4 g camphor. Determine the empirical and molecular formulas of anthraquinone. a. What fraction of the moles of NaCl in this solutithe experiment was such that the boiling point of pure water was 99.7258C.

A 4.7 3 1022 mg sample of a protein is dissolved in water to make 0.25 mL of solution. The osmotic pressure of the solution is 0.56 torr at 258C. What is the molar mass of the protein?

A solid consists of a mixture of NaNO3 and Mg(NO3)2. When 6.50 g of the solid is dissolved in 50.0 g of water, the freezing point of the solution is lowered by 5.238C. What is the composition by mass of the solid mixture?

The vapor pressure of pure benzene is 750.0 torr and the vapor pressure of toluene is 300.0 torr at a certain temperature. You make a solution by pouring some benzene with some toluene. You then place this solution in a closed container and wait for the vapor to come into equilibrium with the solution. Next, you condense the vapor. You put this liquid (the condensed vapor) in a closed container and wait for the vapor to come into equilibrium with the solution. You then condense this vapor and find the mole fraction of benzene in this vapor to be 0.714. Determine the mole fraction of benzene in the original solution assuming the solution behaves ideally.

Liquid A has vapor pressure x, and liquid B has vapor pressure y. What is the mole fraction of the liquid mixture if the vapor above the solution is 30.% A by moles? 50.% A? 80.% A? (Calculate in terms of x and y.) Liquid A has vapor pressure x, liquid B has vapor pressure y. What is the mole fraction of the vapor above the solution if the liquid mixture is 30.% A by moles? 50.% A? 80.% A? (Calculate in terms of x and y.)

Plants that thrive in salt water must have internal solutions (inside the plant cells) that are isotonic with (have the same osmotic pressure as) the surrounding solution. A leaf of a saltwater plant is able to thrive in an aqueous salt solution (at 258C) that has a freezing point equal to 20.6218C. You would like to use this information to calculate the osmotic pressure of the solution in the cell. a. In order to use the freezing-point depression to calculate osmotic pressure, what assumption must you make (in addition to ideal behavior of the solutions, which we will assume)? b. Under what conditions is the assumption (in part a) reasonable? c. Solve for the osmotic pressure (at 258C) of the solution in the plant cell. d. The plant leaf is placed in an aqueous salt solution (at 258C) that has a boiling point of 102.08C. What will happen to the plant cells in the leaf?

You make 20.0 g of a sucrose (C12H22O11) and NaCl mixture and dissolve it in 1.00 kg water. The freezing point of this solution is found to be 20.4268C. Assuming ideal behavior, calculate the mass percent composition of the original mixture, and the mole fraction of sucrose in the original mixture.

An aqueous solution is 1.00% NaCl by mass and has a density of 1.071 g/cm3 at 258C. The observed osmotic pressure of this solution is 7.83 atm at 258C.a. What fraction of the moles of NaCl in this solution exist as ion pairs? b. Calculate the freezing point that would be observed for this solution

The vapor in equilibrium with a pentanehexane solution at 258C has a mole fraction of pentane equal to 0.15 at 258C. What is the mole fraction of pentane in the solution? (See Exercise 57 for the vapor pressures of the pure liquids.)

A forensic chemist is given a white solid that is suspected of being pure cocaine (C17H21NO4, molar mass 5 303.35 g/mol). She dissolves 1.22 6 0.01 g of the solid in 15.60 6 0.01 g benzene. The freezing point is lowered by 1.32 6 0.048C. 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 5 299.36 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?

A 1.60-g sample of a mixture of naphthalene (C10H8) and anthracene (C14H10) is dissolved in 20.0 g benzene (C6H6). The freezing point of the solution is 2.818C. What is the composition as mass percent of the sample mixture? The freezing point of benzene is 5.518C and Kf is 5.128C ? kg/mol

A solid mixture contains MgCl2 and NaCl. When 0.5000 g of this solid is dissolved in enough water to form 1.000 L of solution, the osmotic pressure at 25.08C is observed to be 0.3950 atm. What is the mass percent of MgCl2 in the solid? (Assume ideal behavior for the solution.)

Formic acid (HCO2H) is a monoprotic acid that ionizes only partially in aqueous solutions. A 0.10-M formic acid solution is 4.2% ionized. Assuming that the molarity and molality of the solution are the same, calculate the freezing point and the boiling point of 0.10 M formic acid.

You have a solution of two volatile liquids, A and B (assume ideal behavior). Pure liquid A has a vapor pressure of 350.0 torr and pure liquid B has a vapor pressure of 100.0 torr at the temperature of the solution. The vapor at equilibrium above the solution has double the mole fraction of substance A that the solution does. What is the mole fraction of liquid A in the solution?

In some regions of the southwest United States, the water is very hard. For example, in Las Cruces, New Mexico, the tap water contains about 560 mg of dissolved solids per milliliter. Reverse osmosis units are marketed in this area to soften water. A typical unit exerts a pressure of 8.0 atm and can produce 45 L water per day. a. Assuming all of the dissolved solids are MgCO3 and assuming a temperature of 278C, what total volume of water must be processed to produce 45 L pure water? b. Would the same system work for purifying seawater? (Assume seawater is 0.60 M NaCl.)

Creatinine, C4H7N3O, is a by-product of muscle metabolism, and creatinine levels in the body are known to be a fairly reliable indicator of kidney function. The normal level of creatinine in the blood for adults is approximately 1.0 mg per deciliter (dL) of blood. If the density of blood is 1.025 g/mL, calculate the molality of a normal creatinine level in a 10.0-mL blood sample. What is the osmotic pressure of this solution at 25.08C?

An aqueous solution containing 0.250 mole of Q, a strong electrolyte, in 5.00 3 102 g water freezes at 22.798C. What is the vant Hoff factor for Q? The molal freezing-point depression constant for water is 1.868C ? kg/mol. What is the formula of Q if it is 38.68% chlorine by mass and there are twice as many anions as cations in one formula unit of Q?

Anthraquinone contains only carbon, hydrogen, and oxygen. When 4.80 mg anthraquinone is burned, 14.2 mg CO2 and 1.65 mg H2O are produced. The freezing point of camphor is lowered by 22.38C when 1.32 g anthraquinone is dissolved in 11.4 g camphor. Determine the empirical and molecular formulas of anthraquinone.

Give IUPAC names for the following compounds: CH2CH2CCH3 (d) (e) H3C OH (f) Br CH3 CH3 (b) OH (c) HO CH3 CH3CHCH2CHCHCH3 (a) OH OH

Draw structures corresponding to the following IUPAC names: (a) (Z)-2-Ethyl-2-buten-1-ol (b) 3-Cyclohexen-1-ol (c) trans-3-Chlorocycloheptanol (d) 1,4-Pentanediol (e) 2,6-Dimethylphenol (f) o-(2-Hydroxyethyl)phenol

Is p-hydroxybenzaldehyde more acidic or less acidic than phenol?

The following data for isomeric four-carbon alcohols show that there is a decrease in boiling point with increasing substitution of the OH-bearing carbon. How might you account for this trend? 1-Butanol, bp 117.5 C 2-Butanol, bp 99.5 C 2-Methyl-2-propanol, bp 82.2 C

Rank the following substances in order of increasing acidity: (a) (CH3)2CHOH, HCqCH, (CF3)2CHOH, CH3OH (b) Phenol, p-methylphenol, p-(trifluoromethyl)phenol (c) Benzyl alcohol, phenol, p-hydroxybenzoic acid

p-Nitrobenzyl alcohol is more acidic than benzyl alcohol, but p-methoxybenzyl alcohol is less acidic. Explain.

Predict the products of the following reactions: C CH3 CH3 (a) CH3CH2 C H H H CH3CH2CH2CH2 CH2CH2CH2CH3 (c) CC ? 1. BH3 2. NaOH, H2O2 ? 1. OsO4 2. NaHSO3, H2O (b) ? 1. Hg(OAc)2, H2O

What carbonyl compounds would you reduce to obtain the following alcohols? CH3CH2CHCH2CHCH3 CH3 (a) OH (b) CH2OH

What reagent would you use to accomplish each of the following reactions? OH CH3CHCH2CH2COCH3 (a) CH3CCH2CH2COCH3 O O O ? OH CH3CHCH2CH2CH2OH (b) CH3CCH2CH2COCH3 O O ? ? (c)

What carbonyl compounds give the following alcohols on reduction with LiAlH4? Show all possibilities. (a) (b) (c) (d) (CH3) CH2OH OH 2CHCH2OH CHCH3 OH H

How could you use the addition of a Grignard reagent to a ketone to synthesize 2-phenyl-2-butanol?

How could you use the reaction of a Grignard reagent with a carbonyl compound to synthesize 2-methyl-2-pentanol?

Show the products obtained from addition of methylmagnesium bromide to the following compounds: (a) Cyclopentanone (b) Benzophenone (diphenyl ketone) (c) 3-Hexanone

Use a Grignard reaction to prepare the following alcohols: (a) 2-Methyl-2-propanol (b) 1-Methylcyclohexanol (c) 3-Methyl-3-pentanol (d) 2-Phenyl-2-butanol (e) Benzyl alcohol (f) 4-Methyl-1-pentanol

Use the reaction of a Grignard reagent with a carbonyl compound to synthesize the following compound:

How would you carry out the following transformation, a step used in the commercial synthesis of (S)-ibuprofen? H CH3 OH 3C HH C

What product(s) would you expect from dehydration of the following alcohols with POCl3 in pyridine? Indicate the major product in each case. CH3 OH H (a) (b) H CH3CH2CHCHCH3 OH CH3 (d) CH3CHCCH2CH3 H3C OH CH3 (e) CH3CH2CH2CCH3 OH CH3 H OH CH3 (c)

What alcohols would give the following products on oxidation? CH3CHCHO (a) O (b) CH3 (c) O

What products would you expect from oxidation of the following compounds with CrO3 in aqueous acid? With the DessMartin periodinane? (a) 1-Hexanol (b) 2-Hexanol (c) Hexanal

TMS ethers can be removed by treatment with fluoride ion as well as by acidcatalyzed hydrolysis. Propose a mechanism for the reaction of cyclohexyl TMS ether with LiF. Fluorotrimethylsilane is a product.

Show the mechanism for the reaction of p-methylphenol with 2-methylpropene and H3PO4 catalyst to yield the food additive BHT.

Assume that you need to prepare 5-cholesten-3-one from cholesterol. How could you use IR spectroscopy to tell whether the reaction was successful? What differences would you look for in the IR spectra of starting material and product?

When the 1H NMR spectrum of an alcohol is run in dimethyl sulfoxide (DMSO) solvent rather than in chloroform, exchange of the O]H proton is slow and spinspin splitting is seen between the O]H proton and C]H protons on the adjacent carbon. What spin multiplicities would you expect for the hydroxyl protons in the following alcohols? (a) 2-Methyl-2-propanol (b) Cyclohexanol (c) Ethanol (d) 2-Propanol (e) Cholesterol (f) 1-Methylcyclohexanol

Give IUPAC names for the following compounds: (a) (b) (c) (d)

Draw the structure of the carbonyl compound(s) from which each of the following alcohols might have been prepared, and show the products you would obtain by treatment of each alcohol with (1) Na metal, (2) SOCl2, and (3) DessMartin periodinane. (a) (b)

Predict the product from reaction of the following substance (reddish brown 5 Br) with: (a) PBr3 (b) Aqueous H2SO4 (c) SOCl2 (d) DessMartin periodinane (e) Br2, FeBr3

Predict the product from reaction of the following substance with: (a) NaBH4; then H3O1 (b) LiAlH4; then H3O1 (c) 2 CH3CH2MgBr; then H3O1

Name and assign R or S stereochemistry to the product(s) you would obtain by reaction of the following substance with ethylmagnesium bromide. Is the product chiral? Is it optically active? Explain.

Evidence for the intermediate carbocations in the acid-catalyzed dehydration of alcohols comes from the observation that rearrangements sometimes occur. Propose a mechanism to account for the formation of 2,3-dimethyl-2-butene from 3,3-dimethyl-2-butanol. C + H2O CH3 C H3C H3C CH3 H2SO4 C H3C CH3 H3C CH3 C H OH

Acid-catalyzed dehydration of 2,2-dimethylcyclohexanol yields a mixture of 1,2-dimethylcyclohexene and isopropylidenecyclopentane. Propose a mechanism to account for the formation of both products. Isopropylidenecyclopentane

Epoxides react with Grignard reagents to yield alcohols. Propose a mechanism. H OH O CH3 H H H 1. CH3MgBr 2. H3O+

Treatment of the following epoxide with aqueous acid produces a carbocation intermediate that reacts with water to give a diol product. Show the structure of the carbocation, and propose a mechanism for the second step. H3O+ H2O Carbocation CH3 OH H3C CH3 H

Reduction of 2-butanone with NaBH4 yields 2-butanol. Is the product chiral? Is it optically active? Explain.

The conversion of 3 alcohols into 3 alkyl halides under acidic conditions involves two cationic intermediates. For each reaction, draw the complete mechanism using curved arrows. HCl OH OH Cl (a) Cl HBr HCl (b) OH (c

Identify the type of substitution mechanism (SN1, SN2) involved in the conversion of the alcohol shown into the corresponding alkyl halide. (a) HCl PBr3 OH OH (b) (c) Cl OH Br Br 1. p-TosCl, pyridine 2. NaBr

The conversion of 3 alcohols into alkenes under acidic conditions involves two cationic intermediates. For each reaction, draw the complete mechanism using curved arrows. H3O+ H3O+ H3O+ OH OH OH (a) (b) (c

For each reaction, write the mechanism using curved arrows for the conversion of the alcohol into the corresponding alkene with POCl3. In each case, explain the regiochemistry of the elimination. OH (a) (b) (c) POCl3 Pyridine OH OH POCl3 Pyridine POCl3 Pyridine

The trimethylsilyl (TMS) protecting group is one of several silicon protecting groups for alcohols. For each reaction, draw the mechanism for the protection of (R)-3-bromo-1-butanol with the following silyl chlorides, using triethylamine as the base: (a) tert-butyldimethylsilyl chloride (TBS-Cl) (b) triisopropylsilyl chloride (TIPS-Cl) (c) triethylsilyl chloride (TES-Cl)

When the alcohol below is treated with POCl3 and pyridine, the expected elimination product is formed. However, when the same alcohol is treated with H2SO4, the elimination product is 1,2-dimethylcyclopentene. Propose a mechanism for each pathway to account for these differences. POCl3 pyridine OH H2SO4

Phenols generally have lower pKas than aliphatic alcohols because of resonance stabilization with the aromatic ring. Draw all of the resonance contributors for the phenolate ions below. Make note of how the substituents either stabilize or destabilize the system. (a) (b) (c) O OCH3 NC O O

Give IUPAC names for the following compounds: HOCH2CH2CHCH2OH CH3 (a) (b) OH (c) OH CH2CH2CH3 CH3CHCHCH2CH3 OH HO H H CH3 H H H H (d) OH (e) Ph (f) OH C Br N

Draw and name the eight isomeric alcohols with formula C5H12O.

Which of the eight alcohols that you identified in Problem 17-38 react with CrO3 in aqueous acid? Show the products you would expect from each reaction

Named bombykol, the sex pheromone secreted by the female silkworm moth has the formula C16H28O and the systematic name (10E,12Z)- 10,12-hexadecadien-1-ol. Draw bombykol, showing the correct geometry for the two double bonds.

Carvacrol is a naturally occurring substance isolated from oregano, thyme, and marjoram. What is its IUPAC name? CH3CH CH3 OH Carvacrol CH3

What Grignard reagent and what carbonyl compound might you start with to prepare the following alcohols? (a) OH CH3CHCH2CH3 (b) CH3CH2CHCH2CH3 OH (c) C CH3 (f) CH2OH C (e) H2C CH2OH CH3 HO CH3 C (d)

What carbonyl compounds would you reduce to prepare the following alcohols? List all possibilities. CH3CH2CH2CH2CCH2OH CH3 CH3 (a) (b) H (c) 3C H3C CH3C OH CHCH3 OH CHCH2CH3

What carbonyl compounds might you start with to prepare the following compounds by Grignard reaction? List all possibilities. (a) 2-Methyl-2-propanol (b) 1-Ethylcyclohexanol (c) 3-Phenyl-3-pentanol (d) 2-Phenyl-2-pentanol OH CH3 (e) CH2CH2OH H3C CH2CCH3

How would you synthesize the following alcohols, starting with benzene and other alcohols of six or fewer carbons as your only organic reagents? (b) CH3CH2CH2CHCH2CH2OH CH3 (d) CH3CHCH2CHCH2CH3 CH3 OH C (c) (a) CH2CH2CH3 HO CH3 CH2CH3 OH

What products would you obtain from reaction of 1-pentanol with the following reagents? (a) PBr3 (b) SOCl2 (c) CrO3, H2O, H2SO4 (d) DessMartin periodinane

How would you prepare the following compounds from 2-phenylethanol? More than one step may be required. (a) Styrene (PhCHPCH2) (b) Phenylacetaldehyde (PhCH2CHO) (c) Phenylacetic acid (PhCH2CO2H) (d) Benzoic acid (e) Ethylbenzene (f) Benzaldehyde (g) 1-Phenylethanol (h) 1-Bromo-2-phenylethane

How would you prepare the following compounds from 1-phenylethanol? More than one step may be required. (a) Acetophenone (PhCOCH3) (b) Benzyl alcohol (c) m-Bromobenzoic acid (d) 2-Phenyl-2-propanol

How would you prepare the following substances from cyclopentanol? More than one step may be required. (a) Cyclopentanone (b) Cyclopentene (c) 1-Methylcyclopentanol (d) trans-2-Methylcyclopentanol

What products would you expect to obtain from reaction of 1-methylcyclohexanol with the following reagents? (a) HBr (b) NaH (c) H2SO4 (d) Na2Cr2O7

The following 1H NMR spectrum is that of an alcohol, C8H10O. Propose a structure. Intensity 10 0123456789 ppm Chemical shift ()

Propose structures for alcohols that have the following 1H NMR spectra: (a) C5H12O

Propose a structure consistent with the following spectral data for a compound C8H18O2: IR: 3350 cm21 1H NMR: 1.24 d (12 H, singlet); 1.56 d (4 H, singlet); 1.95 d (2 H, singlet)

The 1H NMR spectrum shown is that of 3-methyl-3-buten-1-ol. Assign all the observed resonance peaks to specific protons, and account for the splitting patterns.

A compound of unknown structure gave the following spectroscopic data: Mass spectrum: M1 5 88.1 IR: 3600 cm21 1H NMR: 1.4 d (2 H, quartet, J 5 7 Hz); 1.2 d (6 H, singlet); 1.0 d (1 H, singlet); 0.9 d (3 H, triplet, J 5 7 Hz) 13C NMR: 74, 35, 27, 25 d (a) Assuming that the compound contains C and H but may or may not contain O, give three possible molecular formulas. (b) How many protons (H) does the compound contain? (c) What functional group(s) does the compound contain? (d) How many carbons does the compound contain? (e) What is the molecular formula of the compound? (f) What is the structure of the compound? (g) Assign peaks in the molecules 1H NMR spectrum corresponding to specific protons

Propose a structure for a compound C15H24O that has the following 1H NMR spectrum. The peak marked by an asterisk disappears when D2O is added to the sample. TMS Intensity 10 0123456789 ppm Chemical shift ()

How would you carry out the following transformations? (a) ? CO2H CO2H CO2H CO2H (b) ? CH2OH (c) ? CH2SH

Benzoquinone is an excellent dienophile in the DielsAlder reaction. What product would you expect from reaction of benzoquinone with 1 equivalent of 1,3-butadiene? From reaction with 2 equivalents of 1,3-butadiene?

Rank the following substituted phenols in order of increasing acidity, and explain your answer: OH CH3O OH OH F OH CN

Benzyl chloride can be converted into benzaldehyde by treatment with nitromethane and base. The reaction involves initial conversion of nitromethane into its anion, followed by SN2 reaction of the anion with benzyl chloride and subsequent E2 reaction. Write the mechanism in detail, using curved arrows to indicate the electron flow in each step. Benzyl chloride Nitromethane anion Benzaldehyde + O C O H H N+ CH2Cl C H

Reaction of (S)-3-methyl-2-pentanone with methylmagnesium bromide followed by acidification yields 2,3-dimethyl-2-pentanol. What is the stereochemistry of the product? Is the product optically active? CH3 CH3CH2CHCCH3 3-Methyl-2-pentanone

Testosterone is one of the most important male steroid hormones. When testosterone is dehydrated by treatment with acid, rearrangement occurs to yield the product shown. Propose a mechanism to account for this reaction. Testosterone O CH3 CH3 OH H H H H O CH3 CH3 H H H

Starting from testosterone (Problem 17-62), how would you prepare the following substances? CH3 CH3 CH3 OH H H H H O O CH3 H H H CH3 CH3 CH3 OH H H H H O O CH3 H H H HO H (b)

p-Nitrophenol and 2,6-dimethyl-4-nitrophenol both have pKa 5 7.15, but 3,5-dimethyl-4-nitrophenol has pKa 5 8.25. Why is 3,5-dimethyl-4- nitrophenol so much less acidic? OH NO2 pKa = 7.15 H3C CH3 OH NO2 pKa = 8.25 OH NO2 pKa = 7.15 H3C CH3

Compound A, C10H18O, undergoes reaction with dilute H2SO4 at 25 C to yield a mixture of two alkenes, C10H16. The major alkene product, B, gives only cyclopentanone after ozone treatment followed by reduction with zinc in acetic acid. Write the reactions involved, and identify A and B.

Compound A, C5H10O, is one of the basic building blocks of nature. All steroids and many other naturally occurring compounds are built from compound A. Spectroscopic analysis of A yields the following information: IR: 3400 cm21; 1640 cm21 1H NMR: 1.63 d (3 H, singlet); 1.70 d (3 H, singlet); 3.83 d (1 H, broad singlet); 4.15 d (2 H, doublet, J 5 7 Hz); 5.70 d (1 H, triplet, J 5 7 Hz) (a) How many double bonds and/or rings does A have? (b) From the IR spectrum, what is the identity of the oxygen-containing functional group? (c) What kinds of protons are responsible for the NMR absorptions listed? (d) Propose a structure for A

Dehydration of trans-2-methylcyclopentanol with POCl3 in pyridine yields predominantly 3-methylcyclopentene. Is the stereochemistry of this dehydration syn or anti? Can you suggest a reason for formation of the observed product? (Make molecular models!)

2,3-Dimethyl-2,3-butanediol has the common name pinacol. On heating with aqueous acid, pinacol rearranges to pinacolone, 3,3-dimethyl2-butanone. Suggest a mechanism for this reaction. CH3 Pinacol H3C H3 CH3 C C HO OH C Pinacolone

As a rule, axial alcohols oxidize somewhat faster than equatorial alcohols. Which would you expect to oxidize faster, cis-4-tert-butylcyclohexanol or trans-4-tert-butylcyclohexanol? Draw the more stable chair conformation of each molecule.

Propose a synthesis of bicyclohexylidene, starting from cyclohexanone as the only source of carbon. Bicyclohexylidene

A problem often encountered in the oxidation of primary alcohols to acids is that esters are sometimes produced as by-products. For example, oxidation of ethanol yields acetic acid and ethyl acetate: CH3CH2OH CH3COH + O CH3COCH2CH3 O CrO3 Propose a mechanism to account for the formation of ethyl acetate. Take into account the reversible reaction between aldehydes and alcohols: HR O C HR HO OR + ROH C

Identify the reagents af in the following scheme: O OH a b e f c d OH Br CH2OH

Galactose, a constituent of the disaccharide lactose found in dairy products, is metabolized by a pathway that includes the isomerization of UDP-galactose to UDP-glucose, where UDP 5 uridylyl diphosphate. The enzyme responsible for the transformation uses NAD1 as cofactor. Propose a mechanism. CH2OH HO HO OH O UDP-glucose O O PO O O Uridine O O P CH2OH HO HO OH O UDP-galactose O O PO O O Uridine O O

Propose structures for alcohols that have the following 1H NMR spectra: (a) C9H12O TMS Intensity 10 0123456789 ppm Chemical shift () Chem. shift 0.88 1.80 2.32 4.54 7.24 Rel. area 3.00 2.00 1.00 1.00 5.00 (b) C8H10O2 TMS Intensity 10 0123456789 ppm Chemical shift ()

Compound A, C8H10O, has the IR and 1H NMR spectra shown. Propose a structure consistent with the observed spectra, and label each peak in the NMR spectrum. Note that the absorption at 5.5 d disappears when D2O is added. 0 20 40 60 80 100 Transmittance (%) 4000 3500 2 3000 2500 1 000 500 1000 500 Wavenumber (cm1) Intensity 10 0123456789 ppm Chemical shift ()

The reduction of carbonyl compounds by reaction with hydride reagents (H: 2) and the Grignard addition by reaction with organomagnesium halides (R: 2 1MgBr) are examples of nucleophilic carbonyl addition reactions. What analogous product do you think might result from reaction of cyanide ion with a ketone? CN H3O+ ?

Ethers can be prepared by reaction of an alkoxide or phenoxide ion with a primary alkyl halide. Anisole, for instance, results from reaction of sodium phenoxide with iodomethane. What kind of reaction is occurring? Show the mechanism. CH3 + I Sodium phenoxide Anisole O OCH3 Na+