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
Additional Problems
Which of the following ions should have the most exothermic ΔH  hydration? A) Ca 2+      B) Na +      C) Sr 2+    D) Mg 2+      E) Al 3+
A solution is formed at room temperature by dissolving enough of the solid solute so that some solid remains at the bottom of the solution.  Which statement below is TRUE? A) The solution is considered unsaturated. B) The solution is considered saturated. C) The solution would be considered unsaturated if it were cooled a bit to increase the solubility of the solid. D) The solution is considered supersaturated. E) None of the above are true.  
Explain in a few words the difference between a mixture and solution.   
Explain what will happen to a supersaturated solution if left in a closed container at a constant temperature over time. 
How much NaCl will remain undissolved if 120 g of NaCl is mixed into 100 g of water at 40°C ? a) 20 b) 40 c) 80 d) 100      
The solubility of a substance is 60 g per 100 mL of water at 15° C. A solution of this substance is prepared by dissolving 75 g in 100 mL of water at 75° C. The solution is then cooled slowly to 15° C without any solid separating. The solution is a) supersaturated at 75° C. b) supersaturated at 15° C. c) unsaturated at 15° C. d) saturated at 15° C.
A mixture of 100 g of K 2Cr2O7 and 200 g of water is stirred at 60°C until no more of the salt dissolves. The resulting solution is poured off, leaving the undissolved solid behind. The solution is now cooled to 20°C. What mass of K2Cr2O7 crystallizes from the solution during the cooling? a) 24 g b) 31 g c) 43 g d) 62 g
Choose the situation below that would result in an exothermic ΔH solution. a. When |ΔH ­solute| > |ΔH­ hydration|   b. When |ΔH­ solute| is close to |ΔH­ hydration|   c. When |ΔH ­solute| < |ΔH­ hydration|   d. When |ΔH­ solvent| >> |ΔH­ solute|   e. There isn’t enough information to determine.
A solution contains 25 g of NaCl per 100.0 g of water at 25 °C. Is the solution unsaturated, saturated, or supersaturated?
Precipitation from a supersaturated sodium acetate solution. The solution on the left was formed by dissolving 156 g of the salt in 100 mL of water at 100 oC and the slowly cooling it to 20 oC. Because the solubility of sodium acetate in water at 20 oC is 46 g per 100 mL of water, the solution is supersaturated. Addition of a sodium acetate crystal causes the excess solute to crystallize from solution.How many grams of sodium acetate are in solution in the third beaker?
The solubility of Cr ( NO3 )3 9 H2O in water is 208 g per 100 g of water at 15 oC. A solution of Cr ( NO3 )3 9 H2O in water at 35 oC is formed by dissolving 313 g in 100 g water. When this solution is slowly cooled to 15 oC, no precipitate forms.At equilibrium, what mass of crystals do you expect to form?
What is a saturated solution?
How does the solubility of a solid in a liquid depend on temperature?
How is this temperature dependence exploited to purify solids through recrystallization?
What are the common units for expressing solution concentration?
Explain the difference between an ideal and a nonideal solution.
Some laboratory procedures involving oxygen-sensitive reactants or products call for using preboiled (and then cooled) water. Explain why this is so.
Solubilities of some ionic compounds in water as a function of temperature.How does the solubility of KCl at 80 oC compare with that of NaCl at the same temperature?
The solubility of Cr ( NO3 )3 9 H2O in water is 208 g per 100 g of water at 15 oC. A solution of Cr ( NO3 )3 9 H2O in water at 35 oC is formed by dissolving 313 g in 100 g water. When this solution is slowly cooled to 15 oC, no precipitate forms.You take a metal spatula and scratch the side of the glass vessel that contains this cooled solution, and crystals start to appear. What has just happened?
Fluorocarbons (compounds that contain both carbon and fluorine) were, until recently, used as refrigerants. The compounds listed in the following table are all gases at 25 oC, and their solubilities in water at 25 oC and 1 atm fluorocarbon pressure are given as mass percentages. Fluorocarbon Solubility (mass %) CF4 0.0015 CClF3 0.009 CCl2F2 0.028 CHClF2 0.30 Which molecular property best predicts the solubility of these gases in water?
A supersaturated solution of sucrose (C12H22O11) is made by dissolving sucrose in hot water and slowly letting the solution cool to room temperature. After a long time, the excess sucrose crystallizes out of the solution. Indicate whether each of the following statements is true or false:After the excess sucrose has crystallized out, the remaining solution is saturated.
A supersaturated solution of sucrose (C12H22O11) is made by dissolving sucrose in hot water and slowly letting the solution cool to room temperature. After a long time, the excess sucrose crystallizes out of the solution. Indicate whether each of the following statements is true or false:After the excess sucrose has crystallized out, the system is now unstable and is not in equilibrium.
A supersaturated solution of sucrose (C12H22O11) is made by dissolving sucrose in hot water and slowly letting the solution cool to room temperature. After a long time, the excess sucrose crystallizes out of the solution. Indicate whether each of the following statements is true or false:After the excess sucrose has crystallized out, the rate of sucrose molecules leaving the surface of the crystals to be hydrated by water is equal to the rate of sucrose molecules in water attaching to the surface of the crystals.
What happens if a solute is added to a saturated solution?
By referring to the figure , determine whether the addition of 40.0 g of each of the following ionic solids to 100 g of water at 40 oC will lead to a saturated solution.NaNO3
By referring to the figure , determine whether the addition of 40.0 g of each of the following ionic solids to 100 g of water at 40 oC will lead to a saturated solution.KCl
By referring to the figure , determine whether the addition of 40.0 g of each of the following ionic solids to 100 g of water at 40 oC will lead to a saturated solution.K2Cr2O7
By referring to the figure , determine whether the addition of 40.0 g of each of the following ionic solids to 100 g of water at 40 oC will lead to a saturated solution.Pb(NO3)2
What kinds of units are used in reporting solubility?
Proteins can be precipitated out of aqueous solution by the addition of an electrolyte; this process is called "salting out" the protein.Do you think that all proteins would be precipitated out to the same extent by the same concentration of the same electrolyte?
What are three steps involved in evaluating the enthalpy changes associated with solution formation?
Which of the following is the best representation of a saturated solution?
Stabilization of an emulsion of oil in water by stearate ions.Which kind of intermolecular force attracts the stearate ion to the oil drop?
The solubility of MnSO4 2 O in water at 20 oC is 70 g per 100 mL of water.Is a 1.24 M solution of MnSO4 2 O in water at 20 oC saturated, supersaturated, or unsaturated?
The solubility of MnSO4 2 O in water at 20 oC is 70 g per 100 mL of water.Given a solution of MnSO4 2 O of unknown concentration, what experiment could you perform to determine whether the new solution is saturated, supersaturated, or unsaturated?
Which of the following solutions is unstable? a) An unsaturated solution b) A saturated solution c) A supersaturated solution d) Both a and b e) Both a and b and c
A solution is formed at room temperature by vigorously dissolving enough of the solid solute so that some solid remains at the bottom of the solution. Which statement below is TRUE?A) The solution is considered unsaturated.B) The solution is considered supersaturated.C) The solution is considered saturated.D) The solution will be considered unsaturated if it were cooled a bit to increase the solubility of the solid.E) None of the above are true.
A saturated solution is defined asA) a solution that is in equilibrium with both pure solvent and undissolved solute.B) a solution that is in equilibrium with pure solvent.C) a solution that is in equilibrium with undissolved solute.D) a concentrated solution.
A solution containing more than the equilibrium amount is called ____________.A) an unsaturated solutionB) a dilute solutionC) a supersaturated solutionD) a concentrated solutionE) a saturated solution
A student mixes 10.0 g of KCIO 3 with 45.0 g of H 2O and stirs it for a long time at 60 °C until the solution is completely clear, then allows it to cool slowly to 20 °C where it remains clear. Which statement about the final clear mixture at 20 °C is correct?a) It is a saturated solution.b) It is an unsaturated solution and can be made saturated by decreasing the temperature.c) It is an unsaturated solution and can be made saturated by increasing the temperature.d) It is a supersaturated solution.
If a solution is supersaturated, thenA) the solute concentration is above the solubility limit, but the system is in equilibrium.B) the solute concentration is below the solubility limit, and more solute can be dissolved.C) the solute concentration is above the solubility limit, and the system is not in equilibrium.D) the solute concentration is at the solubility limit.E) no precipitate will form.
In a saturated solution of a salt in water, ________.A. the rate of crystallization > the rate of dissolutionB. the rate of dissolution > the rate of crystallizationC. seed crystal addition may cause massive crystallizationD. the rate of crystallization = the rate of dissolutionE. addition of more water causes massive crystallization
What term describes the process when two liquids are completely soluble in each other in all proportions?A) solvationB) miscibleC) unsaturatedD) saturatedE) oversaturated 
A beaker in the lab at 25 °C contains a saturated solution. More solid is added to the beaker. Which of the following statements best represents what happens when more solid was added?a. The solution concentration increases as more ions dissolve into solutionb. The solution concentration remains unchanged but there is more solid in the beakerc. The solution concentration decreases as more solid forms in the beaker
A solution that contains a large amount of salt and a small amount of water is said to be a _______ solution. a. dilute b. concentrated c. saturated d. unsaturated
CaCl2 has a solubility of 74 g/100g water at 20 oC. If 37g of CaCl2 are dissolved in 50 g of water at 20oC, consider the following statements:I. The solution is at equilibriumII. The solution is unsaturatedIII. The solution is saturatedIV. The solution is supersaturatedWhich statements are true?A. I, II            B. I, III                       C. I, IV           D. III              E. II
Select the steps that are associated with energy entering the system. Check all that apply.a. the separation of solvent moleculesb. the separation of solute moleculesc. the mixing of solute and solvent molecules
KNO3, KClO3, KCl, and NaCl are recrystallized as follows:Step 1. A saturated aqueous solution of the compound is prepared at 50°C.Step 2. The mixture is filtered to remove undissolved compound.Step 3. The filtrate is cooled to 0°C.Step 4. The crystals that form are filtered, dried, and weighed.(a) Which compound has the highest percent recovery and which the lowest (see Figure 13.19)?
KNO3, KClO3, KCl, and NaCl are recrystallized as follows:Step 1. A saturated aqueous solution of the compound is prepared at 50°C.Step 2. The mixture is filtered to remove undissolved compound.Step 3. The filtrate is cooled to 0°C.Step 4. The crystals that form are filtered, dried, and weighed.(b) Starting with 100. g of each compound, how many grams of each can be recovered?
Most barium compounds are very poisonous; however, barium sulfate is often administered internally as an aid in the X-ray examination of the lower intestinal tract (Figure 15.4). This use of BaSO4 is possible because of its low solubility. Calculate the molar solubility of BaSO4 and the mass of barium present in 1.00 L of water saturated with BaSO4.
By referring to the figure above, determine the minimal mass of each of the following salts required to form a saturated solution in 400 g of water at 30oC.KClO3
By referring to the figure above, determine the minimal mass of each of the following salts required to form a saturated solution in 400 g of water at 30oC.Pb(NO3)2
By referring to the figure above, determine the minimal mass of each of the following salts required to form a saturated solution in 400 g of water at 30oC.Ce2(SO4)3
How does the enthalpy of solution depend on the relative magnitudes of ΔHsolute and ΔHhydration ?
What is an unsaturated solution?
What is a supersaturated solution?
Supersaturated solutions of most solids in water are prepared by cooling saturated solutions. Supersaturated solutions of most gases in water are prepared by heating saturated solutions. Explain the reasons for the difference in the two procedures.
Sketch an enthalpy diagram for the process of dissolving NaI(s) in H2O (exothermic).
A person preparing a fish tank uses boiled (and then cooled) water to fill it. When the fish is put into the tank, it dies. Explain.
For the following solute–solvent combinations, state the sign and relative magnitudes for ΔH1, ΔH2, ΔH3, and ΔHsoln (as defined in Fig. 10‑1 of the text). Explain your answers.Fig. 10-1
Which ion of each pair below has the larger ΔHhydr?
Sketch an enthalpy diagram for the process of dissolving KCl(s) in H2O (endothermic).
Which ion of each pair below has the smaller ΔHhydr?
For the following solute–solvent combinations, state the sign and relative magnitudes for ΔH1, ΔH2, ΔH3, and ΔHsoln (as defined in Fig. 10‑1 of the text). Explain your answers.Fig. 10-1
For the following solute–solvent combinations, state the sign and relative magnitudes for ΔH1, ΔH2, ΔH3, and ΔHsoln (as defined in Fig. 10‑1 of the text). Explain your answers.Fig. 10-1
For the following solute–solvent combinations, state the sign and relative magnitudes for ΔH1, ΔH2, ΔH3, and ΔHsoln (as defined in Fig. 10‑1 of the text). Explain your answers.Fig. 10-1
Give an example of each of the following types of solutions: (b) a gas in a gas
An aqueous solution is saturated in both potassium chlorate and carbon dioxide gas at room temperature. What happens when the solution is warmed to 85˚C?a) Potassium chlorate precipitates out of solution.b) Carbon dioxide bubbles out of solution.c) Potassium chlorate precipitates out of solution and carbon dioxide bubbles out of solution.d) Nothing happens; all of the potassium chloride and the carbon dioxide remain dissolved in solution.
The enthalpy of solution for NaOH is -44.46 kJ/mol. What can you conclude about the relative magnitudes of the absolute values of ΔHsolute and ΔHhydration, where ΔHsolute is the heat associated with separating the solute particles and ΔHhydration is the heat associated with dissolving the solute particles in water?
For the dissolution of LiCl in water, Hsoln = -37 kJ/mol.Which term would you expect to be the largest negative number: Hsolvent, Hsolute, or Hmix?
An ionic compound has a very negative Hsoln in water.Which term would you expect to be the largest negative number: Hsolvent, Hsolute, or Hmix?
When ammonium chloride (NH4Cl) is dissolved in water, the solution becomes colder. What can you conclude about the relative magnitudes of the lattice energy of ammonium chloride and its heat of hydration?
When lithium iodide (LiI) is dissolved in water, the solution becomes hotter. What can you say about the relative magnitudes of the lattice energy of lithium iodide and its heat of hydration?
A KNO3 solution containing 51 g of KNO3 per 100.0 g of water is cooled from 40˚C to 0˚C. What will happen during cooling?
A KCl solution containing 42 g of KCl per 100.0 g of water is cooled from 60  m^circ C to 0 ˚C m^circ C. What happens during cooling?
Substance A is a nonpolar liquid and has only dispersion forces among its constituent particles. Substance B is also a nonpolar liquid and has about the same magnitude of dispersion forces among its constituent particles. When substance A and B are combined, they spontaneously mix.Predict the sign and magnitude of ΔHsoln.
Substance A is a nonpolar liquid and has only dispersion forces among its constituent particles. Substance B is also a nonpolar liquid and has about the same magnitude of dispersion forces among its constituent particles. When substance A and B are combined, they spontaneously mix.Give the signs and relative magnitudes of ΔHsolute, ΔHsolvent, and ΔHmix.
The enthalpy of solution for cesium fluoride is -36.8 kJ/mol. What can you conclude about the relative magnitudes of ΔHsolute and ΔHhydration?
A solution is saturated in both nitrogen gas and potassium bromide at 75 oC. When the solution is cooled to room temperature, what is most likely to happen?
What is the heat of hydration (ΔHhydration)?
(c) Is the beverage unsaturated, saturated, or supersaturated with CO2?
Caffeine is about 10 times as soluble in hot water as in cold water. A chemist puts a hot-water extract of caffeine into an ice bath, and some caffeine crystallizes. Is the remaining solution saturated, unsaturated, or supersaturated?
The solubility of Cr(NO3)3 • 9H2O in water is 208 g per 100 g of water at 15˚C. A solution of Cr(NO3)3 • 9H2O in water at 35˚C is formed by dissolving 313 g in 100 g water. When this solution is slowly cooled to 15˚C, no precipitate forms. Is the solution that has cooled down to 15˚C unsaturated, saturated, or supersaturated?
A solution contains 32 g of KNO3 per 100.0 g of water at 25 oC. Is the solution unsaturated, saturated, or supersaturated?
A solution contains 25 g of NaCl per 100.0 g of water at 25˚C. Is the solution unsaturated, saturated, or supersaturated?
Suppose you are presented with a clear solution of sodium thiosulfate, Na2S2O3. How could you determine whether the solution is unsaturated, saturated, or supersaturated?
This question has multiple parts. Work all the parts to get the most points. In a coffee-cup calorimeter, 1.17 g NH4NO3 was mixed with 55.00 g water at an initial temperature 25.00°C. After dissolution of the salt, the final temperature of the calorimeter contents was 23.34°C. (a) Assuming the solution has a heat capacity of 4.18 J/g •°C, and assuming no heat loss to the calorimeter, calculate the enthalpy of solution (ΔHsoln) for the dissolution of NH4NO3 in units of kJ/mol. (b) In a coffee-cup calorimeter, 1.17 g NH4NO3 was mixed with 55.00 g water at an initial temperature 25.00°C. After dissolution of the salt, the final temperature of the calorimeter contents was 23.34°C. If the enthalpy of hydration for NH4NO3 is -630. kJ/mol, calculate the lattice energy of NH4NO3. 
Potassium nitrate has a lattice energy of -163.8 kcal/mol and a heat of hydration of -155.5 kcal/mol. Part AHow much potassium nitrate has to dissolve in water to absorb 113 kJ of heat? Express your answer using two significant figures.