Science

Q: To make a 2.00 m solution, one could take 2.00 moles of solute and add A) 1.00 L of solvent. B) 1.00 kg of solvent. C) enough solvent to make 1.00 L of solution. D) enough solvent to make 1.00 kg of solution.

Q: To make a 0.500 M solution, one could take 0.500 moles of solute and add A) 1.00 L of solvent. B) 1.00 kg of solvent. C) enough solvent to make 1.00 L of solution. D) enough solvent to make 1.00 kg of solution.

Q: How much water must be added to 40.0 g of CaCl2 to produce a solution that is 35.0 wt% CaCl2? A) 54.0 g B) 74.2 g C) 87.5 g D) 114 g

Q: What volume of 3.00 M CH3OH solution is needed to provide 0. 220 mol of CH3OH? A) 1.52 mL B) 13.6 mL C) 73.3 mL D) 660 mL

Q: What volume of a 0.716 M KBr solution is needed to provide 30.5 g of KBr? A) 21.8 mL B) 42.7 mL C) 184 mL D) 357 mL

Q: What is the weight percent of a caffeine solution made by dissolving 8.35 g of caffeine, C8H10N4O2, in 75 g of benzene, C6H6? A) 0.0 10% B) 0.0 11% C) 10% D) 11%

Q: What is the weight percent of vitamin C in a solution made by dissolving 6.50 g of vitamin C, C6H8O6, in 55.0 g of water? A) 0. 547% B) 1.21% C) 10.6% D) 11.8%

Q: What is the mole fraction of oxygen in a gas mixture that is 37% oxygen and 63% nitrogen by volume? A) 0. 34 B) 0. 37 C) 0. 25 D) 0. 52

Q: What is the mole fraction of I2 in a solution made by dissolving 55.6 g of I2 in 245 g of hexane, C6H14? A) 0. 0715 B) 0. 0770 C) 0. 133 D) 0. 154

Q: What is the mole fraction of ethanol in a solution made by dissolving 29.2 g of ethanol, C2H5OH, in 53.6 g of water? A) 0. 176 B) 0. 213 C) 0. 352 D) 0. 545

Q: Which cation in each set is expected to have the larger (more negative) hydration energy? I. Be2+ or Ca2+ II. Rb+ or Zn2+ A) Be2+ in set I and Rb+ in set II B) Be2+ in set I and Zn2+ in set II C) Ca2+ in set I and Rb+ in set II D) Ca2+ in set I and Zn2+ in set II

Q: At 80C, pure liquid A has a vapor pressure of 700 mm Hg and pure liquid B has a vapor pressure of 940 mm Hg. What is XA for a solution of A and B with a normal boiling point of A) 0.25 B) 0.50 C) 0.75 D) A solution of A and B cannot boil at 80C.

Q: What is the approximate boiling temperature of the liquid formed from the condensation of the vapor above a boiling solution that is 0.70 XA and 0.30 XB? A) 50C B) 55C C) 90C D) 100C

Q: What is the approximate vapor composition above a boiling solution that is 0.70 XA and 0.30 XB? A) 0.70 XA, 0.30 XB B) 0.50 XA, 0.50 XB C) 0.30 XA, 0.70 XB D) 0 XA, 1.00 XB

Q: What is the approximate boiling temperature of a mixture that is 0.70 XA and 0.30 XB? A) 50C B) 75C C) 95C D) 100C

Q: Assume that the vapor at point c is condensed and reboiled. What is the boiling point? A) temperature at point b B) temperature at point c C) temperature at point d D) temperature at point f

Q: Assume that the vapor at point c is condensed and reboiled. What is the vapor composition during reboiling? A) 100% decane B) composition at point b C) composition at point c D) composition at point e

Q: Assume that the vapor at point c is condensed and reboiled. What is the liquid composition of the condensed vapor prior to reboiling? A) 100% decane B) composition at point b C) composition at point d D) composition at point e

Q: Assume that you start with a mixture containing 0.80 mol of decane and 0.20 mol of octane, what is the vapor composition at the boiling point? A) 100% decane B) composition at point b C) composition at point c D) composition at point e

Q: Assume that you start with a mixture containing 0.80 mol of decane and 0.20 mol of octane, what is the liquid composition at the boiling point? A) 100% decane B) composition at point b C) composition at point c D) composition at point e

Q: Assume that you start with a mixture containing 0.80 mol of decane and 0.20 mol of octane, at what approximate temperature will the mixture begin to boil? A) temperature at point a B) temperature at point b C) temperature at point d D) temperature at point f

Q: Assume that you start with a mixture containing 0.80 mol of decane and 0.20 mol of octane, what region of the diagram corresponds to vapor? A) region a B) region b C) region c D) regions a and c

Q: Assume that you start with a mixture containing 0.80 mol of decane and 0.20 mol of octane, what region of the diagram corresponds to liquid? A) region a B) region b C) region c D) regions a and c

Q: Two beakers, one with pure water (light gray) and the other with an aqueous solution of KBr (dark gray), are placed in a closed container represented by drawing (a). Which of the drawings (a)-(d) represents what the beakers will look like after a substantial amount of time has passed? A) drawing (a) B) drawing (b) C) drawing (c) D) drawing (d)

Q: Drawing (1) shows a nonequilibrium system comprised of pure water separated from an aqueous solution by a semipermeable membrane. Shaded spheres represent solute particles and unshaded spheres represent water molecules. Which drawing (2)-(5) represents this system after equilibrium is reached? A) drawing (2) B) drawing (3) C) drawing (4) D) drawing (5)

Q: The following diagram shows a close-up view of the vapor pressure curves for two pure liquids and two different solutions composed of these two liquids. Which curves represent pure liquids and which curves represent the solutions? A) Curves (a) and (b) are the pure liquids and curves (c) and (d) are the solutions. B) Curves (a) and (c) are the pure liquids and curves (b) and (d) are the solutions. C) Curves (a) and (d) are the pure liquids and curves (b) and (c) are the solutions. D) Curves (c) and (d) are the pure liquids and curves (a) and (b) are the solutions.

Q: Which curve is the solvent and what happens to the boiling point when the solute is dissolved in the solvent? A) Curve (a) is the solvent and the boiling point decreases. B) Curve (a) is the solvent and the boiling point increases. C) Curve (b) is the solvent and the boiling point decreases. D) Curve (b) is the solvent and the boiling point increases.

Q: Which curve is the solvent and what happens to the vapor pressure when the solute is dissolved in the solvent? A) Curve (a) is the solvent and the vapor pressure decreases. B) Curve (a) is the solvent and the vapor pressure increases. C) Curve (b) is the solvent and the vapor pressure decreases. D) Curve (b) is the solvent and the vapor pressure increases.

Q: Drawings (1) and (2) show the equilibrium vapor pressures of two pure liquids. Which drawing (3)-(6) represents the equilibrium vapor pressure of a solution made by mixing equal moles of each liquid? A) drawing (3) B) drawing (4) C) drawing (5) D) drawing (6)

Q: Drawing (1) shows the equilibrium vapor pressure of a pure liquid. Which drawing (2)-(5) represents the equilibrium vapor pressure when a nonvolatile solute is dissolved in the liquid? A) drawing (2) B) drawing (3) C) drawing (4) D) drawing (5)

Q: Drawing (1) shows a system in which an equilibrium exists between dissolved and undissolved gas particles at P = 1 atm. According to Henry's law, if the pressure is decreased to 0.5 atm and equilibrium is restored, which drawing (2)-(5) best represents the equilibrium at 0.5 atm? A) drawing (2) B) drawing (3) C) drawing (4) D) drawing (5)

Q: Drawing (1) shows a system in which an equilibrium exists between dissolved and undissolved gas particles at P = 1 atm. According to Henry's law, if the pressure is increased to 2 atm and equilibrium is restored, which drawing (2)-(5) best represents the equilibrium at 2 atm? A) drawing (2) B) drawing (3) C) drawing (4) D) drawing (5)

Q: Which ion-dipole interaction results in the larger (more negative) hydration energy? A) diagram (a) B) diagram (b) C) diagram (c) D) diagram (d)

Q: Which arrows represent Hsolute-solute and Hsolvent-solvent?A) arrow (a) and arrow (b)B) arrow (a) and arrow (c)C) arrow (a) and arrow (d)D) arrow (c) and arrow (d)

Q: Which arrow represents Hsolute-solvent?A) arrow (a)B) arrow (b)C) arrow (c)D) arrow (d)

Q: Which arrow represents Hsoln?A) arrow (a)B) arrow (b)C) arrow (c)D) arrow (d)

Q: Which drawing above represents the system with the second highest entropy? A) drawing (a) B) drawing (b) C) drawing (c) D) drawing (d)

Q: Which drawing above represents the system with the second lowest entropy? A) drawing (a) B) drawing (b) C) drawing (c) D) drawing (d)

Q: Which drawing above represents the system with the lowest entropy? A) drawing (a) B) drawing (b) C) drawing (c) D) drawing (d)

Q: Which drawing above represents the system with the highest entropy? A) drawing (a) B) drawing (b) C) drawing (c) D) drawing (d)

Q: At 25C the vapor pressures of benzene and toluene are 96.0 mm Hg and 30.5 mm Hg, respectively. When a 1:1 molar mixture of benzene and toluene is fractionally distilled, the first fraction will have a mole fraction of benzene that is closest to A) 0.0 B) 0.5 C) 0.7 D) 1.0

Q: A solution of 62.4 g of insulin in enough water to make 1.000 L of solution has an osmotic pressure of 0.305 atm at 25C. Based on these data, what is the molar mass of insulin? A) 621 g/mol B) 5000 g/mol C) 7570 g/mol D) 71,900 g/mol

Q: Naproxen is a commercially important anti-inflammatory agent that can be isolated from the thyroid gland. A solution of 1.138 g of naproxen in 25.00 g benzene has an osmotic pressure of 4.00 atm at 20C. The density of benzene is 0.8787 g/mL at this temperature. Calculate the molar mass of naproxen, assuming it remains intact upon dissolution and the density of the solution equals the density of pure benzene. A) 176 g/mol B) 230 g/mol C) 307 g/mol D) 3.80 105 g/mol

Q: The coolant in automobiles is often a 50/50 % by volume mixture of ethylene glycol, HOCH2CH2OH, and water. At 20C, the density of ethylene glycol is 1.1088 g/mL and the density of water is 0.9982 g/mL. Assuming that the volumes are additive, what is the expected freezing point of a 50/50(v/v)% ethylene glycol/water solution? Kf = 1.86C/m for water. A) -16C B) -17C C) -30C D) -33C

Q: When ethylene glycol, HOCH2CH2OH, is added to the water in an automobile radiator, the effect is to A) lower the boiling point and lower the freezing point. B) lower the boiling point and raise the freezing point. C) raise the boiling point and lower the freezing point. D) raise the boiling point and raise the freezing point.

Q: When 0.500 g of vitamin K is dissolved in 10.0 g of camphor (Kf = 40.0C/m), the freezing point of the solution is 4.43C lower than that of pure camphor. Assuming vitamin K is a nonelectrolyte in camphor, calculate its molar mass. A) 0.451 g/mol B) 55.4 g/mol C) 451 g/mol D) 3.54 104 g/mol

Q: The average osmotic pressure of blood is about 7 atm. Therefore A) the average blood pressure is about 7 atm. B) the average pressure inside the body is about 7 atm above the external pressure. C) a pressure of about 7 atm would be required to prevent osmosis if blood is in contact with pure water across a semipermeable membrane. D) All of these are true.

Q: A solution is made by dissolving 13 g of sucrose, C12H22O11, in 117 g of water, producing a solution with a volume of 125 mL at 20C. What is the expected osmotic pressure at 20C? A) 7.3 atm B) 10 atm C) 14 atm D) 58 atm

Q: Assuming that sea water is a 3.5 wt % solution of NaCl in water, calculate its osmotic pressure at 20C. The density of a 3.5% NaCl solution at 20C is 1.023 g/mL. A) 1.0 atm B) 15 atm C) 29 atm D) 100 atm

Q: How will the osmotic pressure of an aqueous solution change as evaporation occurs? A) The osmotic pressure will increase. B) The osmotic pressure will not change. C) The osmotic pressure will decrease. D) The osmotic pressure will increase or decrease until it equals the vapor pressure of water.

Q: Red blood cells are placed into pure water. Which of the following statements is true? A) Water molecules flow out of the red blood cells, causing them to collapse. B) Water flows into the red blood cells, causing them to swell and burst. C) The osmotic pressure of the cell contents increases, causing the cells to burst. D) The osmotic pressure inside the cells equals the osmotic pressure outside.

Q: Two aqueous solutions, A and B, are separated by a semipermeable membrane. The osmotic pressure of solution A immediately begins to decrease. Which of the following statements is true? A) Solvent molecules are moving from solution B into solution A. B) The initial osmotic pressure of solution B is greater than that of solution A. C) The solvent molecules are moving from the solution of higher osmotic pressure to that of lower osmotic pressure. D) Both B and C are true statements.

Q: Chloroform has a boiling point of 61.1C and dichloromethane has a boiling point of 40.0C. When 0.100 mol of dichloromethane is added to 0.900 mol of chloroform, the resulting solution will have a boiling point A) between 40.0C and 61.1C, but closer to 61.1C. B) between 40.0C and 61.1C, but closer to 40.0C. C) greater than 61.1C. D) less than 40.0C.

Q: An aqueous CsCl solution is 8.00 wt% CsCl and has a density of 1.0643 g/mL at 20C. What is the boiling point of this solution? Kb = 0.51C/m for water. A) 100.27C B) 100.53C C) 103.8C D) 104.3C

Q: A 0.51 m aqueous solution of an unknown solute has a boiling point elevation of 0.62C. The boiling point elevation of a 0.51 m solution of a nonionizing molecular solute in water is 0.26C. How many moles of particles are formed per mole of solute when the unknown solute is dissolved in water? A) 1.4 B) 2.0 C) 2.4 D) 3.0

Q: A solution of 0.2113 g of water dissolved in 25.0 g of a solvent freezes at 11.5C below the freezing point of the solvent. What is Kf for this solvent? A) 0.735C/m B) 1.36C/m C) 5.39C/m D) 24.5C/m

Q: An aqueous solution has a normal boiling point of 102.0C. What is the freezing point of this solution? For water Kb is 0.51C/m andKf = 1.86C/m. A) -0.55C B) -2.0C C) -3.6C D) -7.3C

Q: The normal boiling point of pure benzene is found to be 80.10C. What is the approximate molecular weight of a nonionizing substance if a solution of 3.55 g of the substance dissolved in 100. g of benzene has a normal boiling point of 80.19C? Kb = 5.12C/m for benzene, C6H6. A) 20 amu B) 500 amu C) 2000 amu D) 20,000 amu

Q: What is the freezing point of a solution of 1.43 g MgCl2 in 100 g of water? Kf for water is 1.86C/m for water. A) -0.0279C B) -0.279C C) -0.559C D) -0.838C

Q: In liquid methanol, CH3OH, which intermolecular forces are present? A) Dispersion, hydrogen bonding and dipole-dipole forces are present. B) Only dipole-dipole and ion-dipole forces are present. C) Only dispersion and dipole-dipole forces are present. D) Only hydrogen bonding forces are present.

Q: Which of the following compounds exhibits only dispersion and dipole-dipole intermolecular interactions? A) N2 B) HBr C) CO2 D) H2O

Q: Which substance in each of the following pairs is expected to have the larger dispersion forces? A) Br2 in set I and n-butane in set II B) Br2 in set I and isobutane in set II C) I2 in set I and n-butane in set II D) I2 in set I and isobutane in set II

Q: Which is expected to have the largest dispersion forces? A) C2H6 B) C8H18 C) N2 D) CO2

Q: Which of the following exhibits ion-dipole forces? A) NaCl(s) B) NaCl(aq) C) Na(s) D) Cl2(g)

Q: Which of the following compounds exhibits hydrogen bonding? A) CH3Cl B) HI C) H3C-O-CH3 D) NH3

Q: Which has the smallest dipole-dipole forces? A) CH3F B) HCl C) N2 D) CO

Q: Which compound below could have a zero dipole moment? A) CCl2F2 (tetrahedral) B) CuCl2F2 (tetrahedral) C) PtCl2F2 (square planar) D) SCl2F2 (see-saw)

Q: The HI bond has a length of 161 pm and 4.92% ionic character. What is the experimental dipole moment of HI? A) 0.380 D B) 0.772 D C) 3.80 D D) 7.72 D

Q: Which compound, shown with its dipole moment, is expected to exhibit the smallest percent ionic character? A) HCl, 1.11 D B) HF, 1.83 D C) LiH,6.00 D D) LiF, 6.28 D

Q: AgCl is found to have 78.1% ionic character, and its gas phase dipole moment is 11.5 D. What is the distance between the Ag and Cl atoms in gaseous AgCl? A) 9.19 x 10-10 pm B) 14.7 pm C) 307 pm D) 903 pm

Q: The dipole moment of BrF is 1.29 D, and its bond length is 178 pm. What is the percent ionic character of the Br F bond?A) 3.9%B) 8.5%C) 15%D) 33%

Q: The dipole moment of ClF is 0.88 D, and its bond length is 163 pm. What is the percent ionic character of the Cl F bond?A) 0.54%B) 7.8%C) 11%D) 25%

Q: Which of the following should have the largest dipole moment? A) H2(g) B) CO2(g) C) KCl(g) D) CH3F(g)

Q: Which of the following molecules does not have a dipole moment? A) CH2=CH2 B) NH3 C) CH3NH2 D) HCl

Q: Which has a dipole moment?A) CO2B) CO32-C) SO2D) SO42-

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