Chapter 13: Physical Properties of Solutions HW Pt. 1

Which of the following options correctly describes an ideal solution?

An ideal solution obeys Raoult's law.

Which of the following statements correctly describe the molality and molarity of a solution? Select all that apply.

Both molarity and molality express concentration in terms of moles of solute. M must be calculated using the volume of the solution, not the volume of the solvent.

An aqueous solution of KCl (molar mass 74.55 g/mol) has a molality of 0.25 m and a density of 1.05 g/mL. Which of the options correctly reflect the steps needed to calculate the molarity (M) of the solution? Select all that apply.

M = 0.26 M An aliquot of the solution that contains 1.00 kg of water also contains 18.6 g of KCl.

Which of the following options correctly describe molality? Select all that apply.

Molality is defined as: moles of solute / mass of solvent(in kg) To calculate molality, the mass of solvent is needed.

Select all that apply Which of the following options correctly describe the different ways of expressing the concentration of a solution? Select all that apply.

Molarity is abbreviated using a capital M and is calculated in units of moles/liter. Mole fraction is defined as the number of moles of solute divided by the total number of moles. To calculate mole fraction for a given mass of a reactant or product, the masses of all solution components must be known.

For most gases, what effect does temperature have on their solubility?

Most gases become less soluble as temperature increases.

Select all that apply Select all the statements that correctly describe Henry's law for gases. c = kP

P is the pressure (in atm) of the gas over the solution. c is the molar concentration of the gas at a particular temperature. This law shows that the solubility of a gas increases with pressure.

Match each of the terms in the equation for Raoult's law with the correct description. P1 = χ1Po1

P1 : vapor pressure of the solvent in the solution χ1 : mole fraction of the solvent in the solution Po1 : vapor pressure of the pure solvent

A solution of volatile gases at 25∘C contains a mixture of 1.20 mol of gas A and 1.35 mol of gas B. The vapor pressure of gas A is 273 mmHg, and the total pressure of the mixture is 306 mmHg. In order to calculate the vapor pressure of gas B, which of the following calculations are required?

PB°= (177.53 mmHg(1.35 mol B))1.20 mol A + 1.35 mol B177.53 mmHg(1.35 mol B)1.20 mol A + 1.35 mol B PA = (1.20 mol A1.20 mol A + 1.35 mol B)1.20 mol A1.20 mol A + 1.35 mol B × 273 mmHg

Which of the following statements correctly describe the processes of crenelation and hemolysis? Select all that apply.

Placing blood cells in a hypertonic solution could possibly lead to crenelation. Adding pure water to the blood in significant amounts could potentially cause hemolysis. The process of water leaving the blood cells leads to crenelation.

Which statement correctly describes the movement of molecules during osmosis?

Solvent molecules pass through a porous membrane from a more dilute solution to a more concentrated one.

How does the presence of a strong electrolyte in solution affect the colligative properties of a solution when compared to the same number of moles of a nonelectrolyte solute?

The electrolyte dissociates or ionizes to give a larger number of moles of dissolved particles, with a greater effect on the colligative properties.

Which of the following statements correctly explain the effect of a nonvolatile solute on the vapor pressure of a solution?

The entropy of the solution is higher than that of the pure solvent. Solvent has less tendency to vaporize and vapor pressure is lowered.

Two volatile molecular substances A and B are mixed. If the solution formed is an ideal solution, which of the following must be correct?

The intermolecular forces between A and B molecules are similar to those between A molecules and between B molecules.

Select all the statements that correctly describe freezing point depression.

The larger difference in entropy means more energy must be removed in order for freezing to occur. During freezing, energy must be removed from the system. A solution has greater disorder than pure solvent, resulting in a greater difference in entropy between the liquid and solid phases.

What statement correctly describes the solubility of vitamins?

The molecular structure determines the solubility of vitamins.

Which of the following options correctly explain why the colligative properties of electrolyte solutions are usually less than predicted? Select all that apply.

The presence of an ion pair reduces the effective number of particles in solution. At higher concentrations, electrostatic forces bring about the formation of ion pairs.

A 0.50% by mass solution of KCl (molar mass 74.55 g/mol) in H2O (Kf = 1.86oC/m) has a freezing point of -0.234oC. Select all the options that correctly reflect the calculations needed to determine the experimental value of the van't Hoff factor i for this solution.

The solution contains 0.50 g of KCl per 99.50 g of H2O. ΔTf = 0.125oC for a nonelectrolyte of the same concentration. i = 0.2340.1250.2340.125 = 1.87

What does it mean if two substances are described as miscible?

The substances are completely soluble in each other at any concentration.

The solution process is governed by two factors, _____ and a tendency toward more _____.

enthalpy, disorder

The compound Ca(NO3)2 dissociates in water to form ___ mol of ions for every 1 mol of solute and its van't Hoff factor i is expected to be ___ in an ideal solution. The compound urea (CH4N2O) has an expected i value of ___ .

3,3,1

Which statement correctly describes the relative solubility of HCl and NaCl in CH3OCH3?

HCl (g) will be more soluble in CH3OCH3 because both compounds exhibit dipole-dipole forces.

Match each term describing solutions with the correct definition.

unsaturated : a solution that contains less solute than it has the capacity to dissolve; more solute added will dissolve saturated : a solution that contains the maximum amount of dissolved solute; more solute added will not dissolve supersaturated : a solution that contains more dissolved solute than is present in a saturated solution; the solution is unstable and the solute will separate from it readily

A solute that is nonvolatile is one that does not exert a _______ _________.

vapor pressure

Match each change of enthalpy to the correct step of the solution process.

ΔH > 0 : Solvent-solvent and solute-solute intermolecular forces are overcome. ΔH < 0 : New solvent-solute intermolecular forces are formed. ΔH < 0 or ΔH > 0 : The solution process overall (including all interactions broken and formed) or the heat of solution

Which of the following statements correctly describe the thermodynamics of the solution process? Select all that apply.

ΔHsoln depends on the chemical nature of both the solvent and the solute. The sign of ΔHsoln is influenced by solvent-solvent, solute-solute, and solvent-solute interactions.

Which of the following options correctly show the relationships between the mole fractions of solute and solvent and the vapor pressures of pure solvent and solution? Select all that apply.

ΔP = χ2Po1 P1= χ1Po1

Which of the following statements correctly describe freezing point depression for a solution? Select all that apply.

ΔTf is a positive value. The freezing point constant Kf is characteristic of the solvent. Freezing point depression is proportional to the molality of the solution.

Calculate the freezing point of a solution containing 0.204 mol of ibuprofen in 250. g of ethanol. (Kf for ethanol = 1.99oC⋅kg/mol and Tf = -117.3oC.)

-118.9oC

Match each type of intermolecular force correctly to the type of solution in which each is exhibited. Instructions

-ion-dipole forces: an ionic solute in a polar solvent-ion-induced dipole forces: a nonpolar solute in a polar solvent that also contains dissolved ions-dipole-induced dipole forces: a nonpolar solute in a polar solvent-dispersion forces: present in all solutions; principal intermolecular force when both solvent and solute are nonpolar

Calculate the osmotic pressure of a solution containing 3.55 g of sucrose (C12H22O11; molar mass 342.3 g/mol) in sufficient water to give 825 mL of solution at 22oC.

0.0126 x 0.0821 x 295 = 0.305 atm

Calculate the mass of O2 that will dissolve in 2.50 L of H2O that is in contact with air at 20oC, where the partial pressure of O2 is 0.209 atm. (k for O2 in H2O at 20oC = 1.28 x 10-3 mol/L⋅atm.)

0.0214 g O2

Place the following aqueous solutions in increasing order (lowest at the top of the list, highest at the bottom) of osmotic pressure, assuming ideal behavior. Instructions Choice 1 of 4. 0.10MKBr toggle button 0.10 M KBr Choice 2 of 4. 0.15MCuCl2 toggle button 0.15 M CuCl2 Choice 3 of 4. 0.15Mglucose (C6H12O6) toggle button 0.15 M glucose (C6H12O6) Choice 4 of 4. 0.10MFe(NO3)3 toggle button 0.10 M Fe(NO3)3

0.15M glucose C6H12O6 (0.15RT) 0.10M KBr (0.2RT) 0.10M Fe(NO3)3 (0.4RT) 0.15M CuCl2 (0.45RT)

A solution containing 0.64 g of adrenaline in 36.0 g of CCl4 has a boiling point of 76.99°C (Kb for CCl4 = 5.03°C/m and its normal boiling point is 76.50°C). Place the following steps in the correct order to calculate the molar mass of adrenaline, starting with the first step at the top of the list. Instructions Choice 1 of 4. m=0.495.03= 0.097m toggle button m = 0.495.030.495.03 = 0.097 m Choice 2 of 4. 0.64g3.5×10-3mol= 183 g/mol toggle button 0.64 g3.5 × 10−3 mol0.64 g3.5 × 10-3 mol = 183 g/mol Choice 3 of 4. moles of adrenaline = 0.097mol1kgCCl4× 0.0360 kg CCl4 = 3.5 × 10-3 toggle button moles of adrenaline = 0.097 mol1 kg CCl40.097 mol1 kg CCl4 × 0.0360 kg CCl4 = 3.5 × 10-3 Choice 4 of 4. ΔTb= 76.99 - 76.50 = 0.49°C toggle button ΔTb = 76.99 - 76.50 = 0.49°C

1 deltaT = 76.99 - 76.50 = 0.49C 2 m = 0.49/5.03 = 0.097 m 3 moles of adrenaline = 0.097 mol / 1 kg CCl4 x 0.0360 kg CCl4 = 3.5 x 10^-3 4 0.64 g / 3.5 x 10^-3 mol = 183 g/mol

A solution of glycerol (C3H8O3; molar mass = 92.09 g/mol) in ethanol (C2H5OH; molar mass = 46.07 g/mol) has a molality of 2.45 mol/kg. Correctly order the steps required to calculate the mole fraction of glycerol in this solution.

1. If the molality is 2.45 mol/kg, there are 2.45mol of glycerol in 1.00kg of ethanol 2. 1.00kg ethanol = 1000g x 1mol/46.07g = 21.7mol ethanol 3. total moles = 2.45mol + 21.7mol = 24.2mol 4. Xglycerol = 2.45/24.2 = 0.101

The partial pressure of atmospheric nitrogen is 0.78 atm and the Henry's Law constant for nitrogen in water is 6.10 x 10-4 mol/L⋅atm at 25∘C. What is the concentration of dissolved nitrogen in the water? Choose all that apply.

1.33 x 10-2 g/L 4.76 x 10-4 M

A monoprotic weak acid, HX is at a concentration of 0.0500 M. If the solution has an osmotic pressure of 1.25 atm at 25∘C what is the percent ionization of the solution?

1.60%

Calculate the expected boiling point of a solution containing 0.72 mol of MgCl2 in 1.00 kg of H2O if Kb = 0.512oC/m.

100.0oC + (2.16 x 0.512) = 101.1oC

Concentrated aqueous HCl contains 38.0% by mass of HCl. Calculate the mass of water present in 250. g of this solution.

155 g H2O

A solution that is 0.0400 M in nitrous acid (HNO2) has an osmotic pressure of 1.00 atm at 25∘C. Calculate the percent ionization of HNO2 at this concentration.

2.23%

A solution contains 25.0 g ethanol (C2H5OH; molar mass 46.07 g/mol) in 500. g H2O (molar mass 18.02 g/mol) at 23°C. If the vapor pressure of pure H2O at this temperature is 20.57 torr, What is the vapor pressure of the solution?

20.1 torr

Calculate the vapor pressure for a solution at 25°C containing a mixture of 1.40 g CH2Cl2 and 3.55 g CHCl3 given that the vapor pressures of CH2Cl2 and CHCl3 at 25°C are 415 mmHg and 205 mmHg, respectively.

280. mmHg

A 0.100 M solution of magnesium sulfate (MgSO4) has an experimental van't Hoff factor of 1.3 at 25∘C. What is the osmotic pressure of this solution?

3.18 atm

A 355-mL sample of an aqueous solution containing 0.320 g of an unknown molecular compound has an osmotic pressure of 45.1 mmHg at 42°C. What is the molar mass of the unknown compound?

393 g/mol

What mass of CCl4 (molar mass 153.81 g/mol) is required to prepare a 0.25-m solution using 115 g of hexane (C6H14; molar mass 86.17 g/mol)?

4.42 g

A solution of glucose (C6H12O6; molar mass = 180.16 g/mol) in water has an osmotic pressure of 2.68 atm at 35°C. What is the mass of glucose in 325 mL of solution?

6.21 g

0.045 moles of H2SO4 are dissolved in 55.0 mL of H2O. Given that the density of H2O is 1.00 g/mL, calculate the mass percent of the H2SO4 in this solution.

7.4%

Select all that apply Select all the statements that correctly describe the intermolecular forces in a solution.

A polar molecule like water can induce a partial charge on a nonpolar molecule like carbon dioxide. There are intermolecular forces that exist between an ion and a polar molecule.

What are the features of a nonvolatile solute?

A solute that does not exert a vapor pressure

Which of the following options correctly reflect the effect of a nonvolatile solute on the boiling point of a solution? Select all that apply.

A solution boils at a higher temperature than the pure solvent. The greater the concentration of the solution the higher the boiling point will be. Boiling point elevation occurs because the presence of a nonvolatile solute lowers the vapor pressure of the solvent.

Match the statement regarding disorder of a system on the left with the correct relative freezing point on the right.

A solution which has higher amounts of disorder: Relatively lower freezing point. A pure solvent which has lower disorder.: Relatively higher freezing point.

Select the statement that best describes a volatile solute.

A volatile solute has measurable vapor pressure.

Match each of the following solutes to the correct calculated value for i for an aqueous solution. Instructions

A. HCl would dissociate to form H+ and Cl- ions. So i =2 B. Glucose being a molecular compound doesn't dissociate so i =1 C. MgCl2 dissociate to Mg2+ and 2Cl- ions. So i =3

Select all that apply Which of the following compounds are expected to be soluble in carbon tetrachloride (CCl4) based on structure? Select all that apply.

Br2 C6H6

crenation, hemolysis

Crenation : The shrinking of cells in a hypertonic solution Hemolysis : The swelling and subsequent bursting of cells in a hypotonic solution

Select all that apply Which of the following statements correctly describe solvation? Select all that apply.

During solvation, a solute molecule is surrounded by solvent molecules arranged in a particular way. Solvation is called hydration when the solvent is water. Solvation involves the interaction between solute molecules and solvent molecules.

Select all the statements that correctly describe hemodialysis.

Hemodialysis requires a more porous membrane than osmosis. In hemodialysis, both solvent and small solute molecules pass through a porous membrane. During hemodialysis, small solute molecules are removed from the blood while larger components like proteins are not.

Which of the following statements correctly define the terms hypotonic and hypertonic? Select all that apply.

Hypotonic refers to a solution with a lower concentration of dissolved substances than plasma. Hypertonic refers to a solution with a higher concentration of dissolved substances than plasma.

Which of the following correctly defines an ion pair?

One or more cations and one or more anions held together by electrostatic forces.

Which of the following statements correctly describe the osmotic pressure (π) of a solution? Select all that apply.

Osmotic pressure increases with temperature. Osmotic pressure is directly proportional to the molarity of the solution.

A solution contains 0.32 mol naphthalene in 5.50 mol of toluene at 32°C. Pure toluene has a vapor pressure of 41 torr at this temperature. Which of the following options correctly solve for both P and ΔP for this solution? Select all that apply.

P=39 torr change in P=2.33 tor

Select all that apply Which of the following options correctly describe percent by mass? Select all that apply.

Percent by mass is a unitless number because it is a ratio of two quantities that have the same units. Percent by mass is defined as the ratio of the mass of a solute to the mass of the solution, multiplied by 100.

Which of the following statements correctly defines colligative properties?

Properties of a solution that depend only on the number of dissolved solute particles

Select all that apply Which of the following correctly describe the process of hydration?

Solute particles and water molecules interact via ion-dipole interactions. Individual solute particles are surrounded by water molecules.

Select all the statements that correctly describe the factors that affect solubility.

Temperature affects the solubility of most substances. Pressure has an effect on the solubility of gases in water.

Select all that apply Which of the following options correctly describe the effect of temperature on the solubility of a solid in a given solvent? Select all that apply.

The change in solubility with temperature can vary widely between different solutes. In general, solids are more soluble at higher temperatures than at lower temperatures.

Which of the following statements correctly define or describe solubility?

The solubility of a given substance in a particular solvent varies with temperature.

Select all that apply Which of the following statements correctly describe the role played by disorder in the formation of a solution? Select all that apply.

The solution process is generally accompanied by an increase in disorder. An endothermic solution process may still occur if there is an increase in disorder for this process. Much of the order of a pure solvent and solute is destroyed when the solute dissolves in the solvent.

Which of the following options correctly describe the van't Hoff factor for the solution of an electrolyte? Select all that apply.

The van't Hoff factor is greater than 1 for electrolyte solutions. The van't Hoff factor is used to predict the colligative properties of an electrolyte solution. The van't Hoff factor is predicted from the number of particles the electrolyte will form after dissociation.

Hemodialysis is a process whereby ______.

a semipermeable porous membrane is used to purify the blood.

The solubility of a gas in water usually _____ with increasing temperature.

decreases

To convert a concentration unit based on mass to one based on volume, the of the _________ solution will be required.

density

Freezing point _____ is observed for solutions containing nonvolatile solutes. The entropy of a solution is _____ than that of the pure solvent and the solution therefore freezes at a _____ temperature.

depression, greater, lower

Select all that apply Identify ALL the intermolecular forces exhibited in a solution of CH3OCH3 in CH3Cl.

dipole-dipole forces dispersion forces

I2 (s) has a very low solubility in H2O (l) because the weak _____ forces between I2 and H2O are not strong enough to replace the _____ between the H2O molecules.

dipole-induced dipole; hydrogen bonds

A solution forms when the attractive ___________ between the solute and solvent are _____________ in strength to the solvent-solvent and solute-solute attractions and are therefore able to replace them.

forces, similar

1 mole of a strong electrolyte in solution will have a(n) _____ effect on the colligative properties of the solution than 1 mole of a nonelectrolyte. A strong electrolyte will dissociate or ionize in aqueous solution and therefore the total number of dissolved solute particles is _____ for 1 mole of a strong electrolyte than for 1 mole of a nonelectrolyte solute.

greater, greater

A solution containing a nonvolatile solute always boils at a _____ temperature than the pure solvent. The vapor pressure of the solution is _____ than the vapor pressure of the pure solvent; hence the solution must be heated to a _____ temperature in order for the vapor pressure to equal the atmospheric pressure.

higher, lower, higher

An increase in pressure will cause the solubility of a gas to _____, whereas the solubility of a liquid or solid will usually _____.

increase, not change much

Match each specific solution with the principal intermolecular force exhibited.

ion dipole: Na Cl in CH3CH2OH dipole-induced dipole: O2 in aqueous solution ion-induced dipole: Mg2+ in hexane (C6H14)

Two solutions of equal concentration have the same osmotic pressure. The solutions are said to be _________ to each other.

isotonic

A solution containing a nonvolatile solute will have a(n) ________ vapor pressure than the pure solvent. The change in the vapor pressure is proportional to the _______ fraction of the solute in the solution.

lower, mole

Select all that apply Which of the following expressions correctly represent the percent by mass of a solute in a solution? Select all that apply.

mass of solute / mass of solute + mass of solvent x 100% mass of solute / mass of solution x 100% Percent by mass is defined as the ratio of the mass of a solute to the mass of the solution, multiplied by 100. Percent by mass is a unitless number because it is a ratio of two quantities that have the same units.

Two liquids are _______ if they are completely soluble in each other at all proportions.

miscible

What additional information is required to carry out each of the following concentration term conversions? Instructions

mol to mol- densitymole frac to mol- molar massesmass percent- molar masses and density

Match each concentration term with the correct ratio each represents. Instructions

molarity (M) : mol of solute / L of solution mole fraction (x) : mol of solute / total # of moles present

The ratio moles of solute L / of solution moles of solute is called the _____ of a solution (symbol M), whereas the _____ (symbol m) of the solution is expressed as moles of solute / kg of solvent moles. Molarity is temperature dependent and typically _____ as temperature increases.

molarity, molality, decreases

Select all that apply A solution is prepared by mixing 10.5 g of NaCl (molar mass 58.44 g/mol) with 147 g of H2O (molar mass 18.07 g/mol). The final volume of the solution is 150. mL. Select all the options that correctly reflect the calculations required to determine molality (m) of the solution.

moles NaCl = 0.180 mol m = 0.180 mol / 0.147 kg = 1.22 m

Which of the following expressions correctly represent molality, m, of a solution?

moles of solute / mass of solvent (in kg)

Most solids become _____ soluble in a particular solvent at higher temperatures than at lower temperatures, although there are some exceptions.

more

A saturated solution of a gas in a liquid (in a closed system) is at equilibrium with a fixed number of gas molecules leaving and entering the solution every second. If the pressure on the system is increased, this causes _____ gas molecules to dissolve in order to reestablish equilibrium. A gas is therefore _____ soluble at higher pressures.

more, more

Colligative properties are properties of a solution that depend only on the __________ of solute particles in a given volume of solution, not on their ___________.

number, type

When an ionic substance dissociates in solution, the ions often form ion ___________. which are held together by electrostatic forces. This causes the number of particles in solution to be __________ than predicted from the formula of the compound.

pair, less

The presence of an ion pair ______ the number of particles in solution and ______ the observed colligative properties.

reduces; reduces

A solution that contains the maximum amount of dissolved solute in a fixed quantity of solvent at a particular temperature is called a(n) ___________ solution.

saturated

Henry's law states that the _________ of a gas in a solvent is proportional to the ____________ of that gas above the solution.

solubility, pressure

_________ is defined as the amount of solute that is able to dissolve in a given volume of a specific solvent at a specific ____________.

solubility, temperature

Solvation refers to a __________ particle being surrounded by _________ molecules. If the solvent is water, the process is called ___________.

solute, solvent, hydration

The process by which solute particles are separated from one another and surrounded by solvent molecules is known as _________.

solvation

A semipermeable membrane allows the passage of _____ molecules, but blocks the passages of _____ molecules.

solvent, solute

If a pure solvent is separated from a solution by a semipermeable membrane, solvent particles will pass through the membrane from the _____ to the _____. This process is called osmosis and the _____ pressure (π) is the pressure that must be applied to stop the net flow of solvent.

solvent, solution, osmotic

Match the vitamin type on the left with its solubility capability in the body on the right. Instructions

structure contains multiple polar groups : water-soluble vitamin structure contains mainly hydrocarbon chains : fat-soluble vitamin

Both ______ and _________ affect the solubility of gases in water.

temperature, pressure

In a solution of a strong electrolyte, the calculated van't Hoff factor i is equal to ______.

the number of moles of particles produced by dissociation of 1 mol of the electrolyte