chapter 11: solutions
Mass/volume percent
_________ is encountered in several applications, including the medical field. For example, the concentration of NaCl in a saline IV bag is 0.9%. For every 100 mL of solution, the mass of NaCl present is 0.9 g.
Nonelectrolyte
_________ substances retain their molecular structure when dissolved.
Percent by volume
__________ is most often used when liquids are dissolved in liquids, since it is easy to measure amounts of liquids by their volumes.
saturated solution
a ______ solution contains the maximum concentration of dissolved solute.
increased
An equilibrium exists between the solute molecules in the gas phase and in the solution. An increase in pressure changes this equilibrium, resulting in ______ gas solubility.
titration
To determine the concentration of a measured volume of acid, a known volume of a base of known concentration is added until some sign of a reaction can be observed, such as a color change of an indicator. This laboratory technique is called _______.
percent by volume= (12.5 mL ethanol/ 85.4 mL solution) x 100% = 14.6% 7.30 mL ethanol
To prepare a solution, we dissolve 12.5 mL of ethanol in sufficient water to give a total volume of 85.4 mL. What is the percent-by-volume concentration of ethanol? What volume of ethanol would be present in 50.0 mL of this solution?
87.2%
To prepare a solution, we dissolve 205 mL of ethanol in sufficient water to give a total volume of 235 mL. What is the percent-by-volume concentration of ethanol?
acids, bases, and ionic compounds ; molecular
To summarize, when we determine the composition of a solution we must first classify the substance as an electrolyte or a nonelectrolyte. In aqueous solution,___,____, and ____ form separate ions, and most ______- compounds retain their molecular structure.
solution
a_______ is a homogeneous mixture with uniform composition throughout.
molecular equation: HCl(aq) + NaOH(aq) --> NaCl(aq) + H2O(l) ionic equation: H+(aq) + Cl-(aq) + Na+(aq) + OH-(aq) --> Na+(aq) + Cl-(aq) + H2O(l) spectator ions: Na+ and Cl- net ionic equation: H+(aq) + OH-(aq) --> H2O(l)
consider the reaction between hydrochloric acid and sodium hydroxide, both of which are strong electrolyte. the molecular equation= ____________ the ionic equation= ____________ spectator ions= _____ the net ionic equation= ____________
equivalence point
just beyond the point at which the reaction between the two substances is complete = the __________
insoluble insoluble
most hydroxides are _______, with some exceptions. the Mg(OH)2 in liquid antacids is not one of the exceptions, so we can assume it is ________—thus, it's safe to use as an antacid.
higher; increases
most ionic compounds are more soluble at ______ temperatures, but gases are less soluble as temperature _________.
Partially miscible
________ liquids form solutions over a limited range of compositions.
electrolytes
_________ help maintain water balance between the interior of cells and the fluid that surrounds them.
aqueous
A solution in which the solvent is water is an ______ solution.
normality (N)
A concentration unit similar to molarity called __________ can be used to describe the concentration of certain ions in solution.
Molality= moles of solute/ kilograms of solvent
A concentration unit that uses moles of solute and mass of solvent does not change with temperature. Molality (m) is such a unit. It is the concentration expressed as moles of solute per kilogram of solvent: Molality= ________
1.04M
A solution contains 117 g of potassium hydroxide, KOH, dissolved in sufficient water to give a total volume of 2.00 L. The molar mass of KOH is 56.11 g/mol. What is the molarity of the aqueous potassium hydroxide solution?
8.48 m
A solution contains 22.5 g of methanol, CH3OH, dissolved in sufficient water to give a total mass of 105.3 g. The molar mass of CH3OH is 32.04 g/mol. What is the molality of the aqueous methanol solution?
5.34m
A solution contains 56.7 g of potassium hydroxide, KOH, dissolved in sufficient water to give a total mass of 245.8 g. The molar mass of KOH is 56.11 g/mol. What is the molality of the aqueous potassium hydroxide solution?
(78.2 g NaCl / 58.44 g/mol )= 1.34 mol NaCl 1.34 mol/ 0.525L = 2.55 mol/L = 2.55 M
A solution contains 78.2 g NaCl dissolved in sufficient water to give a total volume of 0.525 L. The molar mass of NaCl is 58.44 g/mol. What is the molarity of this solution?
unsaturated solution
A solution that contains less than the maximum possible amount of solute is called a _________ solution.
Parts per million = (grams of solute/ grams of solution) x 10^6
A solution that is 1 ppm of a solute contains 1 part solute in 1 million parts of solution. Parts per million is calculated by dividing the mass of solute by the mass of solution and multiplying by 1 million (106): Parts per million = _________
hydrochloric acid + sodium hydroxide--> sodium chloride + water
Acid-Base Titrations: consider another type of reaction that takes place in solution, an acid-base neutralization reaction. In such a reaction, an acid reacts with a base, normally forming a salt and water. The formation of water molecules from hydrogen ions and hydroxide ions is common to all aqueous neutralization reactions. The acid-base reaction involves the donation of a hydrogen ion by an acid and the acceptance of that hydrogen ion by a base. A common example is the reaction between hydrochloric acid and sodium hydroxide, both of which are strong electrolytes: hydrochloric acid + sodium hydroxide-->____________
H+ ; OH−
Acids provide ____ions in aqueous solution. Bases neutralize acids and often provide ____ ions in aqueous solution.
equivalence point
Although Titration can be applied to other types of reactions, we will focus on acid-base titrations. To carry out the process, we add one solution to a known volume of the other solution, until just beyond the point at which the reaction between the two substances is complete. We can often tell when we have reached this point, called the________, by a change in the color of an indicator, a substance that has been added to the system and is sensitive to changes in acid or base content.
decreases
An important consequence of the reduced gas solubility at higher temperatures occurs in cases of thermal pollution of water. It happens around power plants cooled by a river or stream when warm water is returned to its source after it has been used by the plant for cooling. When the water temperature of the river or stream increases, the solubility of oxygen in the water ________, threatening the survival of fish and certain other aquatic organisms. Algae blooms are often observed under low-oxygen conditions, because algae thrive in this environment.
CH3CH2OH (l) ---H2O(l)---> CH3CH2OH(aq)
Another nonelectrolyte compound, ethanol, CH3CH2OH, behaves the same way. It retains its molecular structure in aqueous solutions. We can describe the mixing of ethanol with water using the following equation:
cold; hot
Athletes often use instant ____ packs to reduce swelling and ___ packs to relieve pain.
molecular
BaCl2(aq) + K2SO4(aq) ----> BaSO4(s) + 2KCl(aq) this is a ______________ equation, because it represents the substances as if they existed as molecules (or formula units) rather than dissociating into ions when they are dissolved in solution. BaCl2(aq) is a shorthand way of indicating that Ba2+ and Cl− ions are present in the solution. Similarly, for K2SO4(aq), K+ and ions are present. The precipitate BaSO4(s) does not exist as separate ions because it's insoluble in water.
solvent
Because molality does not vary with temperature, it is useful in experiments involving temperature-dependent properties. It is also useful for examining properties that depend on the number of solute particles in solution. To calculate molality, we must determine the number of moles of solute and the mass of solvent. Note that it is the mass of the _________—not of the solution—that is needed
0.01 mg
Because parts per million is often used to report the amount of pollutants in water, scientists sometimes look at this concentration unit in another way. For aqueous solutions, parts per million is essentially equal to milligrams of solute per liter of solution. For example, the acceptable level of arsenic in drinking water is reported as 0.01 ppm. This means that 1 L of drinking water cannot contain more than ________ mg of arsenic.
London dispersion forces; miscible
Carbon tetrachloride, CCl4, and hexane, C6H14, are nonpolar liquids, so both have__________ as their only intermolecular attraction. Because they are alike in their intermolecular forces, they are _______.
endothermic; exothermic
Chemical cold packs consist of ammonium nitrate and water in separate compartments in the pouch. When the contents are allowed to mix, the bag feels cold. Is the process endothermic or exothermic? Chemical hot packs usually contain water separated from calcium chloride or magnesium sulfate. These pouches get warm when the seal between the water and the solute is broken and a solution forms. Is the process endothermic or exothermic?
decreasing
Concentrations with units that contain a volume term can vary with temperature. Suppose we have a 0.1 M NaCl solution. If the temperature increases, will the molarity stay the same? No, because the volume of the solution will change. When liquids are heated, they expand slightly, so the ions that make up a sodium chloride solution will be spread over a larger volume, thus _________ the molarity. A concentration unit that uses moles of solute and mass of solvent does not change with temperature. Molality (m) is such a unit. It is the concentration expressed as moles of solute per kilogram of solvent
greater
Consider NaCl and water molecules before they form a solution. The ions in solid NaCl are arranged in an organized pattern. When they mix with the water molecules to form a solution, their energies become more dispersed and their arrangements become less ordered. The resulting solution has a _______ entropy than the NaCl and water before mixing.
a) 2.15% b) 0.538 g
Consider a solution prepared by adding 2.70 g acetic acid, CH3CO2H, to 122.8 g of water. (a) What is the percent by mass concentration of acetic acid in this solution? (b) What mass of acetic acid is present in 25.0 g of this solution?
mass of solution = 25.0g NaCl + 125.0g H2O = 150.0 g (25.0g NaCl / 150.0g solution) x 100% = 16.7% mass NaCl= 10.0g solution x (16.7g NaCl/100.0g solution) = 1.67 g NaCl
Consider a solution prepared by adding 25.0 g NaCl to 125.0 g of water. (a)What is the percent by mass concentration of NaCl in this solution? (b)What mass of 10.0 g of this solution? NaCl is present in 10.0 g of this solution?
nonpolar nonpolar
Consider the vitamin structures. Except for the −OH group on the end, the vitamin A molecule consists of many carbon-carbon and carbon-hydrogen bonds. It is essentially _______. Fat molecules are _______ because they consist of similar carbon-carbon and carbon-hydrogen bonds. Since vitamin A and fat molecules are both nonpolar, vitamin A is stored in fatty tissues in the body.
ions; ions
Electrolyte solutions contain a solute that dissociates or ionizes in a solvent, producing _____. The presence of ____ allows electric current to pass through the solution.
negative; exothermic
Energy being released to the surroundings corresponds to a _____ value of the heat of solution and an ______ process.
homogeneous
Ethanol is completely miscible with water. That is, water and ethanol can be mixed in any proportion to give a _______ solution.
soluble ionic
Examples of electrolytes are ______ compounds such as NaCl, strong acids, and strong bases.
nonpolar; increases
Gases such as N2 and O2 are slightly soluble in water because they are ______. They become even less soluble as temperature _______.
C6H12O6, H2O2
Glucose and fructose remain as intact molecules when dissolved in water. Both have the same formula, __________ but they differ in how their atoms are arranged. They each retain their molecular structure when dissolved in water, in the same way as does the simpler molecular compound, hydrogen peroxide, _______. A 3% solution of this compound is often used to sterilize cuts and scrapes.
36.5 g NaCl
How many grams of NaCl would be contained in 245.0 mL of a 2.55 M NaCl solution?
solubility
How readily or completely a solute dissolves in a solvent is its __________.
ion-dipole forces.
In a sodium chloride solution, several water molecules surround each ion, creating multiple ________
solute; solvent
In a sodium chloride solution, the sodium chloride is considered the _____ because it dissolves and is present in a lesser amount. Water is the ______ because it does the dissolving and is present in a greater amount.
entropy
In addition to energy, another factor is important in the solution process. This factor, called ______, is a measure of the tendency for the energy of a system's particles to become more dispersed, resulting in an increase in randomness of the system.
intermolecular forces that are relatively weak
In contrast to ionic compounds that are held together by ionic bonds, covalent molecules are held together by ______ that are _________ .
soluble Insoluble
In general, a ______ ionic compound dissociates into ions when dissolved in water. ___________ compounds remain mostly undissociated in their ionic, crystalline structure.
increases decreases
In general, the solubility of ionic solids in water __________ with increasing temperature and Gas solubility ________ with increasing temperature.
polar solvents; nonpolar
In order for a solid to be soluble in a given solvent, the energy released by the solvation process must compensate for all (or at least most) of the energy required to break up forces at work both within the solute and within the pure solvent. Thus, ionic solids are generally soluble in ________ solvents, where very strong interactions occur between the dipoles of the solvent molecules and the dissolved ions. A ________ solvent cannot interact with dissolved ions strongly enough to overcome the ionic forces within the ionic solid crystal.
sodium chloride; simple sugars
In sports drinks, __________ helps reestablish electrolyte balance. The drinks also contain ___________, such as fructose or glucose.
new intermolecular forces
In the formation of a solution, energy must be supplied to break the intermolecular forces and/or bonds in both the solute and solvent. It comes, at least in part, from the _________ that form between solute and solvent particles
Pb2+ and I−
In this solution, some of the PbI2 dissolves, forming _____ and ____ ions. Eventually the remaining undissolved PbI2 settles to the bottom of the beaker.
polar
In vitamin C, several −OH groups make the molecule _____. Since water is polar, vitamin C is soluble in aqueous body fluids.
immiscible
Liquids such as cyclohexane, C6H12, and water are essentially insoluble in one another and are called _________.
completely miscible
Liquids such as ethanol and water are called __________ which means that they can form solutions in all proportions.
Mass/volume percent= (grams of solute/ volume of solution) x 100%
Mass/volume percent is a concentration unit that is similar to the percents of mass and volume. Mass/volume percent is calculated by dividing the solute mass by the volume of solution and multiplying by 100%: Mass/volume percent= ________
additive not always additive.
Masses are _______; that is, the mass of solution is equal to the sum of the masses of solute and solvent. Volumes are ________ It is possible for the volume of a solution to be different from the sum of the volumes of the solute and solvent. Depending on the attractive forces between solute and solvent, the solution may have a greater or lesser volume than the separated components. So, the total volume of a solution must be measured, not calculated from its components.
order to a less ordered state
Matter spontaneously changes from a state of _________ to a _____, unless energy changes oppose it.
lower; lower
Matter tends to undergo changes that lead to a ________ energy. This happens when energy is released to the surroundings. Thus, solutions will form more readily when the solution has a _______ energy than the separate solute and solvent.
molarity= (moles of solute/ liters of solution)
Molarity (M) is one of the most commonly used expressions of concentration in the laboratory. You may remember from Chapter 4 that molarity (molar concentration) is the ratio of moles of solute to the volume of solution in liters: molarity= _________
increase
Most solutions form because the makeup of a solution naturally tends toward an _______ in randomness of particles and
supersaturated solution
Much less common is a solution that contains more than the expected maximum amount of solute, and is called a __________ solution.
weak; random
Nonpolar liquids dissolve in one another because the forces between the molecules in the pure liquids are _____ and also because of the tendency for matter to become more _______.
immiscible
Oil, a nonpolar substance, does not mix with vinegar, an aqueous solution consisting of polar substances. The intermolecular forces between oil and water are not strong enough to overcome the intermolecular forces between oil molecules and the hydrogen bonding between water molecules. Oil and water are ________.
electrolytes
Other ________ in sports drinks include potassium citrate, magnesium chloride, calcium chloride, and potassium phosphate.
Percent by mass = (grams of solute/ grams of solution) x 100%
Percent by mass is calculated by dividing the solute mass by the mass of solution and multiplying by 100%: Percent by mass = __________
Percent by volume = (volume of solute/ volume of solution) x 100%
Percent by volume is calculated by dividing the solute volume by the solution volume and multiplying by 100%. Calculating percent by volume is similar to calculating percent by mass. We simply substitute volumes for masses in the equation shown earlier for percent by mass: Percent by volume =________
dipole-dipole interactions London dispersion forces
Polar----> solvent-solvent ______ Nonpolar---> solvent-solvent ________
Potassium nitrate is an ionic compound, so ionic bonds between K+ and ions must be broken for the solution to form. The solvent, H2O, is polar covalent, with hydrogen bonding as the primary intermolecular force between water molecules. Some of these hydrogen bonds must be broken for the solution to form.
Potassium nitrate, KNO3, is used to treat high blood pressure. It dissolves in water to form an aqueous solution. Describe the forces that must be broken for the solution to form.
BaCl2(aq) + K2SO4(aq) ----> BaSO4(s) + 2KCl(aq)
Precipitation Reactions: Patients undergoing X-ray treatment to diagnose digestive tract problems drink a suspension of barium sulfate. Barium sulfate can be prepared from a precipitation reaction in which solutions of barium chloride and potassium sulfate are mixed. Recall from Section 5.4 that in a precipitation reaction the cation of one ionic compound combines with the anion of another ionic compound to form an insoluble, solid substance, called a precipitate. The reaction between barium chloride and potassium sulfate forms the precipitate barium sulfate along with soluble potassium chloride: molecular equation: ______ ----> _______
insoluble
When Megan and Derek studied the active ingredients in antacids, they identified bases such as magnesium hydroxide and calcium hydroxide, both of which are _______ in water.
higher higher
Pressure also affects the solubility of gases in the bloodstream. Hospital patients who suffer from respiratory problems are given higher concentrations of oxygen, often through a mask. Within the mask, the oxygen partial pressure is _______ than it is in air. With this _______ oxygen pressure, more oxygen dissolves in the patient's bloodstream with each breath, so the patient does not have to breathe as often to maintain an adequate oxygen supply.
soluble
Scuba divers must consider the effect of gas solubility at increased pressures under water. Recreational divers typically breathe ordinary air that has been compressed into a tank. It is about 78% nitrogen, which the body can handle under normal conditions of surface atmospheric pressure. As a diver descends, however, the increase in pressure causes more nitrogen to dissolve in the bloodstream and body tissues. If the diver surfaces too rapidly—causing a rapid decrease in pressure—the nitrogen comes out of solution as bubbles in tissues and in the bloodstream. These bubbles cause the neurological and circulatory symptoms of the "bends." One way to prevent this medical issue is to use a gas mixture of helium and oxygen (called heliox). This special air is sometimes used by military and professional divers because helium is not as ______ in the blood and tissues as nitrogen.
Parts per billion = (grams of solute/ grams of solution) x 10^9
Similarly, a solution that is 1 ppb of a solute contains 1 part solute in 1 billion parts of solution. Parts per billion is calculated by dividing the mass of solute by the mass of solution and multiplying by 1 billion (109): Parts per billion =____________
nonpolar; polar
Soaps and detergents are made of molecules or ions that have a polar end and a nonpolar end. The _______ end is attracted to oil stains on skin or clothing, and the _______ end is attracted to water. In this way, the oil can be removed by soapy water.
dissociate completely into ions; strong
Soluble ionic compounds, strong acids, and strong bases __________ They are considered to be _______ electrolytes because their aqueous solutions are good conductors of electricity.
soluble insoluble
Solute= Ionic solvent polar= ______ solvent nonpolar = _____
soluble; insoluble
Solute= Polar solvent polar= ______ solvent nonpolar = _____
insoluble; soluble
Solute= nonpolar solvent polar= ______ solvent nonpolar = _____
sodium chloride ; glucose
Solutions of sodium chloride and glucose vary in their ability to conduct electricity because _________ dissociates into ions and ________ does not.
polar
Sucrose (table sugar) is a molecular compound that's highly soluble in water. Predict whether sucrose molecules are polar or nonpolar.
hydration; solvation cations; anions
The process by which a solute particle is surrounded by solvent water molecules in a solution is called _________. (If the solvent is not water, the process is called _________.) The hydrated ions are surrounded by water molecules oriented so that the partially negative polar ends of the water molecules are closest to the ________ and the partially positive polar ends are closest to the _______-.
mol of NaOH= 25.00mL H2SO4 solution x (1L / 1000mL) x (0.1000M H2SO4/ L H2SO4 solution) x (2 mol NaOH/1 mol H2SO4) = 0.005000 mol NaOH volume NaOH solution= 25.05mL NaOH solution x (1L/1000 mL) = 0.02505L NaOH solution Molarity= moles solute/ liters of solution = 0.005000 mol NaOH / 0.02505 L solution = 0.1996M NaOH mass Na2SO4= 0.005000mol NaOH x (1 mol NaSO4/ 2 mol NaOH) x (142.0422g / 1 mol NaSO4) = 0.355 g Na2SO4
Suppose a titration is run in which 25.05 mL of NaOH solution of unknown concentration reacts with 25.00 mL of 0.1000 M H2SO4 solution. The chemical equation that summarizes the reaction is as follows: H2SO4(aq) + 2NaOH(aq) --> 2H2O(l) + Na2SO4(aq) What is the molarity of the NaOH solution? What mass of Na2SO4 could be isolated upon completion of this reaction?
a). step 1: mol BaCl2= 130ml BaCl2 solution x (1L/1000mL) x (0.250mol BaCl2/L BaCl2 solution) = 0.0325 mol BaCl2 step 2: now use the mole ratio in the chemical equation to calculate the moles of K2SO4 required for the reaction: mol K2SO4=0.0325mol BaCl2x(1 mol K2SO4/1 mol BaCl2)= 0.0325 mol K2SO4 step 3: volume of K2SO4 solution= 0.0325mol K2SO4 x(1 L K2SO4 solution/ 0.450 mol K2SO4) = 0.0722 L K2SO4 solution We can interpret this volume of K2SO4 solution as the amount of solution that has enough moles of K2SO4 (0.0325 mol) to react with all the BaCl2. 0.0722 L = 72.2mL K2SO4 solution b).mol BaSO4=0.0325mol BaCl2x(1mol BaSO4/1mol BaCl2) =0.0325mol BaSO4 Mass BaSO4=0.0325mol BaSO4 x (233.4g BaSO4 /1 mol BaSO4)=7.59g BaSO4
Suppose we want to prepare BaSO4 by adding 0.450 M K2SO4 to 130.0 mL of 0.250 M BaCl2. Recall that the balanced equation is BaCl2(aq) + K2SO4(aq) --> BaSO4(s) + 2KCl(aq) a) What volume of the K2SO4 solution is required to react completely with the BaCl2? b). How many grams of BaSO4 will precipitate?
more
Temperature affects the solubility of most substances in water. For example, if you like your tea sweet, you can easily stir more sugar into a cup of hot tea than a frosty glass of iced tea. That's because sugar is _____ soluble in hot water than in cold.
increase
The _______ in entropy upon mixing a solute and solvent helps drive the solution process, especially those processes that are endothermic.
insoluble; soluble
The bases Mg(OH)2 and Ca(OH)2 are ______ because the ionic bonds between the metal ions and hydroxide ions are very strong. The energy released by the formation of ion-dipole attractions does not provide enough energy to break the ionic bonds in these bases. Other bases, such as sodium hydroxide and potassium hydroxide, are ______ because the strength of their ionic bonds is weaker.
Parts per million = (grams of solute/ grams of solution) x 10^6 Parts per million = (3.0x 10^-4g mercury/ 500.0g fish) x 10^6= 0.60ppm 0.14 mg Hg
The concentration of mercury found in fish varies among region and type of fish. Large predator fish such as swordfish can contain more than 1 ppm, which is considered too high by Food and Drug Administration (FDA) standards. Eating fish containing this level of mercury is a risk to developing nervous systems in unborn babies and children. In a healthy adult, mercury is removed from the body naturally, but slowly. If a 500.0-g piece of swordfish contains 3.0 × 10−4 g of mercury, what is the concentration of mercury in this fish in units of parts per million (ppm)? How many milligrams of mercury would be present in a 0.50-lb serving of this swordfish?
heat of solution
The difference between the energy required for the separation of solute and solvent and the energy released upon formation of ion-dipole interactions is the __________
ion and a polar molecule
The force of attraction between an _______ and a _______ is called an ion-dipole force.
multiply; divide
The key to solving problems that involve solution concentrations is to realize that concentration is a ratio that can be used as a conversion factor. If volume is known and we want to calculate moles, we simply_________ by the molarity. If moles are given and we want to calculate volume, we ________ by molarity.
end point
The point at which the indicator changes color is technically called the ________, which may be slightly different from the equivalence point but is usually a good approximation.
small
The ppm and ppb units represent very _______ concentrations. For example, one grain (or crystal) of salt in a cup of salt is about 1 ppm, and one grain in a bathtub filled with salt is about 1 ppb.
Polar Nonpolar
The solubility (or miscibility) of liquids in other liquids depends largely on the polarity of the solute and solvent molecules. _________ liquids dissolve in other polar liquids because the intermolecular forces formed between solute and solvent molecules are strong enough to overcome the strong solute-solute and solvent-solvent dipole-dipole interactions. _______ liquids do not dissolve in polar liquids—at least not to any great extent—because the intermolecular forces between solvent and solute are not strong enough to overcome the solute-solute and solvent-solvent London dispersion forces.
unsaturated; 45 g NaCl
The solubility of NaCl at 25°C is 36 g/100 g H2O. Is the solution described in the example considered saturated, supersaturated, or unsaturated? What is the maximum mass of NaCl that would dissolve in 125.0 g of H2O?
gases (but not of liquids or solids)
The solubility of ______(but not _______) is strongly affected by pressure.
directly proportional; increase
The solubility of a gas in a liquid is _________ to the pressure of the gas above the liquid. This makes sense in terms of a dynamic equilibrium. An _______ in pressure increases the number of gas particles immediately above the solution, increasing the chance that some will dissolve.
increases
The solubility of most solids ________ in water as the temperature of the solution increases.
water
The solvent is usually present in the largest amount but this is not always the case. For example, ethanol, CH3CH2OH, and water can dissolve in each other in all proportions (they are completely miscible), so the relative amounts do not differentiate the solvent from the solute. In such cases, _____ is considered the solvent, even when the other substance is present in greater quantity.
solute; solvent
The substance being dissolved is the ____ (usually present in the lesser amount), and the substance doing the dissolving is the _______ (usually present in the greater amount).
exothermic
The sum of the energies (E1 + E2) required to separate the solute and to separate the solvent equals the amount that must be absorbed to form a solution. When the new ion-dipole forces of attraction form, energy is released. When this amount is greater than the energy absorbed, the solution process is ___________.
1; 1 N
The term is useful in acid-base chemistry because it identifies the moles of H+ ions—known as equivalents—available in a reagent bottle. For example, a 1-L solution that contains 1 mol of H2SO4 has 2 equivalents of H+ available, so it is said to be a 2 N solution. On the other hand, a 1-L solution containing 1 mol of HCl has only ____ equivalent available, so it is _______. Although molarity is more often used in chemistry labs now, equivalents and milliequivalents are still commonly used in the medical profession.
fat-soluble ; nonpolar; nonpolar; water soluble
Vitamin A is a ________ vitamin. It is a ring of carbon atoms attached to a long chain of additional carbon atoms. Although it has a polar −OH group at one end, the molecule is mostly _______. Fat molecules are also mostly ________. Notice that the vitamin C molecule lacks a long nonpolar carbon chain. It is _______ because it has several −OH groups.
removes
Water that has been boiled is often described as having a flat taste, because boiling ______ all the gases that were dissolved in the water.
0.1373M
We need 28.18 mL of 0.2437 M HCl solution to completely titrate 25.00 mL of Ba(OH)2 solution of unknown concentration. What is the molarity of the barium hydroxide solution?
parts per million (ppm) or parts per billion (ppb)
We often encounter very dilute solutions in which the concentration is too small to express conveniently as a percentage. For this reason the amounts of pollutants in water are often reported in units of __________ or _________
London dispersion forces
When a solution forms between a nonpolar solute and a nonpolar solvent, different attractive forces between the molecules must be broken. For example, consider a solution in which iodine, I2, dissolves in carbon tetrachloride, CCl4. ________ are broken between the solute molecules and between the solvent molecules. New London dispersion forces form between the solute and solvent molecules.
114 mL 3.88 g
When a solution of lead(II) nitrate is mixed with a solution of potassium chromate, a yellow precipitate forms according to the equation Pb(NO3)2(aq) + K2CrO4(aq) --> PbCrO4(s) + 2KNO3(aq) What volume of 0.105 M lead(II) nitrate is required to react with 100.0 mL of 0.120 M potassium chromate? What mass of PbCrO4 solid forms?
positive sodium ; negative chloride ion
When a substance dissolves in water to produce ions, the ions are attracted to water molecules by ion-dipole forces. for example NaCl is the solute in the solvent, water, the partially negative oxygen atoms on the water molecules arrange themselves around the _______ ion. The partially positive hydrogen atoms on the water molecules are attracted to the _________.
strongly attracted
When an ionic compound dissolves in water, the dissociated ions are _______ to the polar water molecules, helping in the solution process.
Ionic bonds in the solute break. Hydrogen bonds between water molecules break. Ion-dipole forces form between ions and water molecules.
When an ionic compound dissolves in water, the process can be summarized as follows: ______ bonds in the solute break. _______ bonds between water molecules break. __________ form between ions and water molecules.
moles of that reactant; coefficients
When running a titration, we use the amount of one substance in a chemical reaction to calculate the amount of another. In titration calculations, the volume of the reactant solution of known concentration is used to calculate the __________. The moles of the other reactant are obtained from the _______ in the balanced equation, and this value is used with the volume of the solution of unknown concentration to calculate its molarity.
positive; endothermic
When the separation processes require more energy than the solvation process releases, the heat of solution is ________, and the overall dissolving process is ______. The container in which the solution is made may feel cool to the touch because the solution process absorbs energy from the surroundings.
negative; exothermic
When the solvation process provides more energy than is needed to separate the pure solute and solvent particles, the heat of solution is __________, and the overall dissolving process is _________. In this case the container in which the solution is made may feel warm because the solution process releases energy to the surroundings.
always additive
When two gases are mixed at constant pressure and temperature, their volumes are _________
greater
You observe the effect of pressure on solubility every time you open a bottle or can of a carbonated beverage. These beverages are bottled under a pressure of CO2 ______ than atmospheric pressure. When you remove the bottle cap, the pressure of CO2 decreases. You can hear the excess gas leave the container. Some of the CO2 that had been dissolved in the solution escapes and forms gas bubbles
Ionic
_____ bonds hold the ions of NaCl together.
London dispersion forces and hydrogen bonds (Hydrogen bonding is the stronger of the two intermolecular forces in water.)
______ and _____ bonds hold the molecules of pure water together. (________is the stronger of the two intermolecular forces in water.)
Pure ionic
______ compounds require high temperatures to break their bonds.
Weak
______ electrolytes are usually weak acids and bases.
Three long carbon chains
______ make a fat molecule largely nonpolar.
ion-dipole force
______= an intermolecular force between an ion and a polar molecule.
Acid-base titrations
_______ can be used to determine the amount of acid in aspirin or the amount of base in an antacid.
Polar; nonpolar
_______ solvents dissolve polar or ionic solutes, while _______ solvents dissolve nonpolar solutes
Henry's law
_______ states that the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas above the liquid.
entropy
_______= a measure of the tendency for the energy of matter to become more dispersed.
Titration
________ is the process of determining the concentration of one substance in solution by reacting it with a solution of another substance that has a known concentration.
nonpolar will dissolve
polar solutes such as sucrose dissolve in polar solvents. However nonpolar solutes are usually insoluble in water and other polar solvents, and polar solutes are usually insoluble in _______ solvents. For example, nonpolar oil and water don't mix, but polar ethanol and water mix in any proportion. A nonpolar organic solvent can remove a grease stain on clothing, but water can't. these solubility trends can be summarized by a general rule of thumb called "like dissolves like." That is, when the polarity of the solvent is similar to the polarity of the solute, the solvent ______ the solute.
miscible
the ability of liquids to mix in all proportions =_______
dissociation; ionization
the term _______ describes the process of dissolving for compounds that consist of ions. When a compound that is not ionic provides ions when dissolved in water, the process is called ___________.
strong electrolyte ; weak electrolyte nonelectrolyte
we can determine whether a compound has dissociated into ions in solution if the solution conducts electricity. A solute that dissociates completely into ions in aqueous solution is a ___________ electrolyte A _______ electrolyte dissociates only partially into ions. A ________ does not dissociate into ions
polar
when an ionic compound dissolves, the ions become solvated and form ion-dipole interactions with the solvent.. This occurs only when the solvent molecules are ________. If we reason that an ionic compound is the extreme of polarity, then the rule "like dissolves like" holds for dissolving an ionic compound in a polar solvent
endothermic
when the sum of the energies (E1 + E2) required to separate solute and to separate solvent particles is greater than the energy released from new solute-solvent interactions. these solution processes are ________.
increase
with gases, an _______ in temperature increases the kinetic energy of the molecules. The increased kinetic energy breaks the intermolecular forces between the solute gas particles and the solvent molecules, allowing dissolved gas to escape more readily from the solution into the gas phase.
