Chem 1046 Ch 12

Front 1

what is a solution?

Back 1

is a homogenous mixture, that has the same composition throughout

Front 2

What are the components of a homogenous mixture?

Back 2

2 non polar or 2 polar components
a polar and a non polar do not make a homogenous mixture

Front 3

what are the solute?

Back 3

-a minor component
-the component of the solution that is dissolved into the solvent

Front 4

what are the solvent?

Back 4

-major component
-the liquid in which the solute is dissolved in

Front 5

what is entropy?

Back 5

is a measure of energy randomness or energy dispersal in a system.
the more disorder the system is, the larger the value of entropy

Front 6

why entropy imposrtant in discussing the fromation of solutions?

Back 6

in general, a process that oncrease the amount of disorder in a stsyem is more likely to occur that one that does not. Since forming a solution increases the amount of disorder, entropy favors the formation of a solution.

Front 7

what does th statement "like dissolves like" mean with respect to solution fromation?

Back 7

means two polar liquids or 2 nonpolar liquids will usually mix ( because /\Hsoln = 0), but a polar and a nonpolar liquid will not usually mix (because /\H soln >>0)
-polar solutes tend to dissolve with polar solvents, and that nonpolar solute tend to dissolve with nonpolar solvents. Polar solutes do not dissolve well in nonpolar solvents and nonpolar solutes do not dissolve well in polar solvents

Front 8

how does the solubility of a solid in a liquid depend on temperature?

Back 8

temperature is a measure of kinetic energy of the molecules. The increase in temperature is an increase in kinetic energy. Molecules move faster and will thus dissolve at a faster rate and will dissolve more.
-the solubility of a solid ina liquid usually increases as temperature increases, though as fig.12.11 indicates there are a few exceptions.

Front 9

how is this temperature dependence exploited to purify solids through recrystallization?

Back 9

as the temperature increases the ability for the solute to dissolve increases. when the 'supersaturated' solution cools the excess solute begins to crystalize leaving the impurities behind until the cooled solution contains a maximum amount of dissolved solute.

Front 10

what is an ideal solution and how is it different from a nonideal solution?

Back 10

an ideal solution is a solution that follows Raoult's law at all concentrations for solute and solvent.
-plot of pressure vs mole fraction would be linear
-just as ideal gas is a gas whose components obey the ideal gas law, an ideal solution of volitile liquids is a solution whose components obey Raoult's law (pA = XApA0. Unlike gases, ideal solution are relatively rare, but will form (to a good first approximation) when mixing two similar liquids, such as benzene (C6H6) and toluene (C6H5CH3)

Front 11

what is a nonideal solution and how is it different from an ideal solution?

Back 11

-a nonideal solution is a solution that does not follow Raoult's law at all concentrations for solvent and solute
-a plot of pressure vs mole fraction would not be linear and would have a nonideal solution.

Front 12

what are colligative properties?

Back 12

-properties of solutions of nonvolatile solutes with volatile solvents.
-properites that at most depend only on the physical properties of the solvent and the concentration of solutes partciles.
-properties that depend on the amount of the solute but not on the type
-any property of a solution consisting of a volatile solvent and a nonvolatile solute

Front 13

what do the colligative properties depend on?

Back 13

1) the physical properties of the solvent
2) the number or concentration of solute particles

Front 14

what are the 4 coligative properties?

Back 14

-vapor pressure lowering
-boiling point elevation
-freezing point depression
-osmotic pressure

Front 15

which molecule would you expect to be more water soluble in water, CCl4 or CH2Cl2?

Back 15

-both have tetrahedral molecular geometry.
-CCl4 is nonpolar because th C-Cl bonds cancel each other out.
-CH2Cl2 is polar; the C-Cl bonds have a higher dipole movement than C-H bonds

Front 16

when lithium iodide (LiI) is dissolved in water the solution becomes hotter.
a)is the dissolution of lithium iodide endothermic or exothermic?
b)what can you say about the relative magnitudes of the lattice energy of litium iodide and its heat of hydration?

Back 16

a) it is exothermic because the reaction produces heat
b)the process is exothermic, /\Hsolution < 0

Front 17

when lithium iodide (LiI) is dissolved in water the solution becomes hotter
c)sketch a qualitative diagram similar to figure 12.7 for the dissolution of LiI.

Back 17

?

Front 18

when lithium iodide (LiI) is dissolved in water the solution becomes hotter
d)why does the solution form? and what drives the process?

Back 18

?

Front 19

A solution contains 32. g of KNO3 per 100.0 g of water at 25. *C
Is the solution unsaturated,
saturated, or supersaturated?

Back 19

?

Front 20

An aqueous KNO3 solution is made using 72.5 g of KNO3 dissolved to a total solution volume of 2.00L.
Calculate the molarity, molality, and the mass percent KNO3 in the solution. Assume a density of 1.05 g/mL for the solution.

Back 20

?

Front 21

A solution os prepared by dissolving 20.2 mL of methanol (CH3OH) in 100.0 mL of water at 25*C. The final volume of a solution is 118.0 mL. The densities of methanol and water at this temperature are 0.782 g/mL and 1.000 g/mL, respectively. Calculate
a)molarity
b)molality
c)percent by mass
d)mole fraction
e)mole percent

Back 21

?

Front 22

A solution contains naphthalene (C10H8) dissolved in hexane (C6H14) at a concentration of 12.35% naphthalene by mass. Calculate the vapor pressures at 25.0*C of hexane above the solution. The vapor pressure of pire hexane at 25.0*C is 151torr

Back 22

?

Front 23

A solution cantains a mixture of petane and hexane at room temperature. The solution has a vapor pressure of 258. torr. Pure pentane and hexane have vapor pressures of 425 torr and 151 torr, respectively, at room temperature. What is the mole fraction compsition of the mixture. Assume ideal behavior.

Back 23

?

Front 24

An ethylene glycol solution contains 21.2 g of ethylene glycol (C2H6O2) in 85.4 mL of water. Determine the freezing point and boiling point of the solution. Assume a density of 1.000 g/mL for water.

Back 24

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Front 25

An aqueous solution containing 35.9 g of an unknown molecular nonelectrolytic compound in 150.0 g of water found to have a freezing point of -1.30*C. Calculate the molar mass of the unknown compound.

Back 25

?

Front 26

calculate the osmotic pressure of a solution containing 18.75 mg of hemoglobin in 15.0 mL solution at 25.0*C. The molar mass of hemoglobin is 6.5 x 10^4 g/mol

Back 26

?

Front 27

A 0.100 M ionic solution has an osmotic pressure of 8.3 atm at 25*C. Calculate Van't Hoff factor (i) for this solution.

Back 27

?

Front 28

A gas has a Henry's law constant of 0.112 M/atm. What total volume of solution is needed to completely dissolve 1.65 L of the gas at a pressure of 725 torr and a temperature of 25.0*C?

Back 28

?

Front 29

molarity (M)

Back 29

amount of solute (in mol) / volume solution (in L)
-mol / L
-(M)

Front 30

molality (m)

Back 30

-amount of solute (in mol) / mass of solvent (in kg)
-mol / kg

Front 31

mole fraction (X)

Back 31

-amount of solute (in mol) / total amount of solute and solvent (in mol)

Front 32

mole percent (mol %)

Back 32

-((amount of solute (in mol) / total amount of solute and solvent (in mol))
all multiplied by 100
-%

Front 33

parts by mass

Back 33

-((mass of solute / mass of solution)) x multiplicatiopn factor

Front 34

percent by mass (%)

Back 34

--((mass of solute / mass of solution)) x multiplication factor of 100

Front 35

parts per million by mass (ppm)

Back 35

-((mass of solute / mass of solution)) x multiplicatiopn factor of 10^6

Front 36

parts per billion by mass (ppb)

Back 36

-((mass of solute / mass of solution)) x multiplicatiopn factor of 10^9

Front 37

parts by volume (%, ppm, ppb)

Back 37

-(volume of solute / volume of solution) multiplication factor