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Mixtures and Solutions
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Mixtures
Homogeneous mixtures
Mixture: Mixing two or more substances in which each substance retains its chemical
properties .
Homogenous mixture: A mixture whose ingredients cannot be distinguished .
Solute: The substance that dissolves .
Solvent: The medium that dissolves the solute .
Types of solutions
The type of solution depends on the physical state of solute and solvent,
Solute SolventExample Solution type
Oxygen (gas) Nitrogen (gas) Air Gas
Carbon Dioxide (Gas) Water (Liquid) Carbonated water Liquid
Oxygen (Gas) Water (Liquid) Sea water Liquid
Ethylene Glycol (Liquid) Water (Liquid) Antifreeze Liquid
Ethanolic Acid (Liquid) Water (Liquid) Vinegar Liquid
Sodium chloride (solid) Water (liquid) Sea water Liquid
Mercury (liquid) silver (solid) Dental amalgam Solid
Carbon (solid) Iron (solid) Steel Solid
When a substance is dissolved in another, there are two possibilities,
✓ the substance dissolves, in this case the dissolved substance is called soluble substance.
✓ the substance does not dissolve, in this case it is called insoluble substance .
In case of two liquids, the names changed to a miscible and immiscible.
1) Classify the following substances as soluble or insoluble .
Sugar in water __________________________ ______________ ____
Sand in water __________________________ ______________ ____
Oil with water __________________________ ______________ ____
Vinegar with water __________________________ ______________ ____
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Heterogeneous mixtures
Heterogeneous mixture: A mixture in which the ingredients are not fully mixed together.
Which can distinguish the components .
Suspension
Suspension: A mixture containing particles that settle out if left undisturbed.
The suspended particle diameters are more than 1000nm, the suspension components are
separated using a filter paper. Such as mud .
Thixotropic suspensions
Suspensions will separate into two distinct layers if left undisturbed for a while—a solid like
substance on the bottom and water on the top. However, when stirred, the solid like substance
quickly begins flowing like a liquid.
On the other hand, there are another type of suspensions which form solid substance in
response to the movement, It can be used in constructions in earthquake areas.
Colloids
Colloid: A heterogeneous mixture made up of medium-volume particles, larger than atoms.
Colloidal particle diameters range from 1nm to 1000nm and are and do not settle out, such as
milk, the components of milk can’t be separated by settling or filtration.
The mixture contains more than one substance, but the quantities of substances are different,
the substance in abundance is called the dispersion medium, while the particles of other
substances (dispersed particles)
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Types of colloids
Dispersion medium
Dispersed particles
Example Classification
Solid Solid Colored gemstone Steel in solid
Liquid Solid blood / Gelatin Solid in liquid
solid liquid butter, cheese Solid emulsion
liquid liquid milk, mayonnaise Emulsion
solid gas marshmallow, soaps that float Solid foam
liquid gas whipped cream, beaten egg white Foam
gas solid aerosol smoke, dust in air Solid
What prevent the dispersed particles in a colloid from settling out?
✓ Electrostatic layers around particles
There are charged or polar atomic groups on the surface of
the dispersed particles that attract the positive or negative
charged areas on the dispersion medium. As the electrostatic
layers around the particles repel each other, they remain in
the mixture and do not precipitate .
✓ Brownian motion
Brownian motion: the erratic movement of colloid particles .
Discovered by a Scottish scientist named Robert Brown by the
movement of pollen in water. It produces a collision of the
dispersion medium with the dispersed particles. These collisions prevent particle deposition .
2) List two ways to settle the colloid particles out of the mixture?
1. The stirring of an electrolyte (ionic compound solution) in a colloidal mixture, causes the
molecules to clump together and precipitated in the end .
2. Heating, where heat gives particles enough kinetic energy to overcome electrostatic
forces, causing the precipitation of dispersed particles .
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Tyndall effect
The diluted heterogeneous mixture does not appear
cloudy or opaque like concentrated colloids, but it
does not pass light as efficiently as the homogeneous
solutions, we can see this clearly when a beam of
sunlight passes through fog or clouds .
Tyndall effect: Scattering the light due to the
presence of dispersed particles or suspended in the
heterogeneous mixture .
3) What is the difference between a concentrated heterogeneous solution and a diluted
heterogeneous solution when trying to pass light
through them?
The heterogeneous solution appear as opaque
substance, which does not pass the light, while the
diluted mixture appears transparent, passing light but
dispersing it .
4) Why does the diluted mixture scatter the light while concentrated mixture appears
opaque?
Due to the low number of particles dispersed in the diluted mixture .
5) Compare between the homogeneous, collide, and suspension mixture
Suspension colloid Homogeneous mixture
Definition
Particle volume
Tyndall
phenomenon
Components
precipitation
Example
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Define the following,
6) Solvent: __________________________________________________________________
7) Solute: ___________________________________________________________________
8) Dispersion medium: ________________________________________________________
9) Dispersion medium: ________________________________________________________
10) Why does it more difficult to drive during fog with high lights than using low lights? _____________________________________________________________________________________________________________________________________
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11) Explain why the dissolved particles remain dispersed in the colloidal mixture . _____________________________________________________________________________________________________________________________________
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12) What causes Brownian motion? _____________________________________________________________________________________________________________________________________
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Solution Concentration
Concentration: A measure of how much solute is dissolved in a specific amount of solvent .
The concentration can be expressed qualitatively using a
diluted term or concentrated,
Dilute solution: A solution that contains a small amount of
solute .
Concentrated solution: A solution containing a greater
amount of solute .
Among the methods of calculating the concentration is the molarity, which is preferred by
chemists, mention the reason .
Molarity (Molar concentration) =solute moles number
solution volume in liters
The equation shows the number of solute moles and the number of particles, so chemists
prefer the use of molar .
Quantitative calculation of concentration
Percent by mass
Is the ratio of the solute mass to the mass of the solution expressed as a percent.
The mass of the solution is equal to the sum of dissolved solid and solvent.
Percent by mass = 𝒎𝒂𝒔𝒔 𝒐𝒇 𝒔𝒐𝒍𝒖𝒕𝒆
𝒎𝒂𝒔𝒔 𝒐𝒇 𝒔𝒐𝒍𝒖𝒕𝒊𝒐𝒏 × 100
13) A sample of 3.6 g table salt NaCl added to 100g of water, Calculate the percentage by mass
of NaCl salt .
14) What is the percent by mass of NaHCO3 in a solution containing 20.0 g of NaHCO3
dissolved in 600.0 mL of H2O?
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Mass dissolved = 3.6g
Solvent mass = 100g
Percentage =?
Solution mass = Solvent mass + Solute mass
3.6 g + 100.0 g = 103.6 g
Percent by mass = 𝑚𝑎𝑠𝑠 𝑜𝑓 𝑠𝑜𝑙𝑢𝑡𝑒
𝑚𝑎𝑠𝑠 𝑜𝑓 𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛 × 100
= 3.6 g
103.6 g × 100 = 3.5%
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15) You have 1500.0 g of a bleach solution. The percent by mass of the solute sodium
hypochlorite (NaOCl) is 3.62%. How many grams of NaOCl are in the solution?
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16) In previous question, how many grams of solvent are in the solution?
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17) The percent by mass of calcium chloride in a solution is found to be 2.65%. If 50.0 g of
calcium chloride is used, what is the mass of the solution?
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Percent by volume
the ratio of solute to solution volume, usually used to calculate mixed fluid ratios .
Biodiesel is a clean-burning alternative fuel that is produced from renewable resources.
Biodiesel can be used in diesel engines with little or no modifications.
18) What are the advantages of Biodiesel?
Biodiesel is simple to use, biodegradable, nontoxic, and it does not contain sulfur or aromatics.
It does not contain petroleum, but it can be blended with petroleum diesel to create a
biodiesel blend. B20 is 20% by volume biodiesel, 80% by volume petroleum diesel.
percentage by volume = 𝒔𝒐𝒍𝒖𝒕𝒆
𝒗𝒐𝒍𝒖𝒎𝒆 𝒐𝒇 𝒔𝒐𝒍𝒖𝒕𝒊𝒐𝒏 100 ×
19) What is the percent by volume of ethanol in a solution that contains 35 mL of ethanol
dissolved in 155 mL of water?
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20) What is the percent by volume of isopropyl alcohol in a solution that contains 24 mL of
isopropyl alcohol in 1.1 L of water?
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21) If 18 mL of methanol is used to make an aqueous solution that is 15% methanol by volume,
how many milliliters of solution is produced?
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Molarity (Molar concentration) (M)
The number of moles of solute per liter of solution.
(M)= 𝒎𝒐𝒍𝒆𝒔 𝒐𝒇 𝒔𝒐𝒍𝒖𝒕𝒆
𝑺𝒐𝒍𝒖𝒕𝒊𝒐𝒏 𝑽𝒐𝒍𝒖𝒎𝒆(𝑳)
When one liter of a solution contains (1mol) one mol of the solute the concentration is 1 mol
1L
, 1M (one molar)
22) Determine What is the molar concentration of a liter solution with 0.5 mol of solute?
Number of solute moles = 0.5 mol
Solution volume = 1.0 L
The molarity =?
(M)= 𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 𝑠𝑜𝑙𝑢𝑡𝑒
𝑆𝑜𝑙𝑢𝑡𝑖𝑜𝑛 𝑉𝑜𝑙𝑢𝑚𝑒(𝐿)
0.5mol
1.0L= 0.5M (0.5 Molar)
23) A 100.5-mL intravenous (IV) solution contains 5.10 g of glucose (C6H12O6 ). What is the
molarity of this solution? The molar mass of glucose is 180.16 g/mol.
Mass dissolved = 5.10 g
Solution volume = 100.5 mL
The molarity =?
1) Calculate the number of dissolved moles
5.10g C6H12O6 × 1𝑚𝑜𝑙
180.16𝑔 = 0.0283 mol C6H12O6
2) Convert volume to liter
100.5 mL × 1𝐿
1000 𝑚𝐿 = 0.1005 L
3) Concentration calculations
(M)= 𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 𝑠𝑜𝑙𝑢𝑡𝑒
𝑆𝑜𝑙𝑢𝑡𝑖𝑜𝑛 𝑉𝑜𝑙𝑢𝑚𝑒(𝐿)
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0.0283 mol0.1005 L
= 0.282 M
24) What is the molarity of an aqueous solution containing 40.0 g of glucose (C6H12O6 ) in 1.5L
of solution?
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25) Calculate the molarity of 1.60L of a solution containing 1.55g of dissolved KBr.
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26) What is the molarity of a bleach solution containing 9.0 g of NaOCl per liter of bleach?
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27) How much calcium hydroxide (Ca(OH)2), in grams, is needed to produce 1.5L of a 0.25M
solution?
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Preparing Molar solutions
To prepare a 1L water solution of 1.50 M concentration of CuSO4.5H2O copper II sulfate, follow
these steps :
1. calculate the mass of copper sulphate necessary to prepare 1.50 mol
1.50 mol CuSO4. 5H2O × 249.7 𝑔
1 𝑚𝑜𝑙 = 375 g CuSO4. 5H2O
2. Put the previous mass 375 g in a small amount of water less than 1L and dissolve it until
dissolving completely .
3. Complete the solution with water until it reaches 1L
In our reactions we do not necessarily use all the previous quantity. A reaction may require
only 100mL of substance, so the required quantity should only be prepared so as not to waste
large quantities of chemicals. To prepare less than 1L of substance we use other calculations .
To prepare 100 mL of 1.50 M CuSO4.5H2O which is the same as the previous concentration but
less quantity we follow the following steps,
1. calculate the mass of copper sulphate necessary to prepare 1.50 mol in 1L 1.50 mol CuSO4.5H2O
1L ×
249.7 𝑔
1 𝑚𝑜𝑙 =
375 g CuSO4.5H2O
1L
2. convert the appropriate volume from 1L to 100 mL 375 g CuSO4.5H2O
1L× 100 mL ×
1𝐿
1000 𝑚𝐿 = 37.5 g CuSO4.5H2O
3. Dissolve the previous mass 37.5 g CuSO4.5H2O in a small amount of water and then fill
it up to 100 mL
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28) How many grams of CaCl2 would be dissolved in 1.0 L of a 0.10M solution of CaCl2?
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29) How many grams of CaCl2 should be dissolved in 500.0 mL of water to make a 0.20M
solution of CaCl2?
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30) How much NaOH are in 250 mL of a 3.0M NaOH solution?
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31) What volume of ethanol (C2H3OH) is in 100.0 mL of 0.15M solution? The density of ethanol
is 0.7893 g/mL.
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Diluting molar solutions
We usually use chemicals in specific quantities that are known. These quantities may vary
between mass, volume, number of moles or concentration. These quantities are called
standard quantities, which are constant in all laboratories and are used for measuring other
quantities. One of the most commonly known substances is HCl hydrochloric acid standard
solution, its concentration is 12M
It is not necessarily necessary to use the solution in the laboratory with the same
concentration. We may need a solution containing less concentration, so we will have to dilute
the solution. To do this we add a quantity of solvent, and the important question is what is the
appropriate amount of concentrated solution that we need to use to add the solvent?
In diluting process, we add an amount of solvent to specific amount of the solution, so what
changes is the volume of the solution, on the other hand the number of moles of solute still
the same. We calculate the number of moles of solute in the solution from the equation
(M)= 𝒎𝒐𝒍𝒆𝒔 𝒐𝒇 𝒔𝒐𝒍𝒖𝒕𝒆
𝑺𝒐𝒍𝒖𝒕𝒊𝒐𝒏 𝑽𝒐𝒍𝒖𝒎𝒆(𝑳)
𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 𝑠𝑜𝑙𝑢𝑡𝑒 = Molarity × 𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛 𝑉𝑜𝑙𝑢𝑚𝑒(𝐿)
Case 1 (before diluting) n1 = M1 × V1
Case 2 (after diluting) n2 = M2 × V2
Because the number of moles of solute doesn’t change, so n1 = n2 so,
Dilution Equation
M1V1=M2V2 M1 Molarity before diluting
V1 Volume before diluting
M2 Molarity after diluting
V2 Volume after diluting
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32) What volume, in milliliters, of 2.00M calcium chloride (CaCl2) stock solution would you use
to make 0.50 L of 0.300M calcium chloride solution?
M1 = 2.00 M CaCl2
V1 = ?
M2 = 0.300 M CaCl2
V2 = 0.50 L
M1V1=M2V2
V1 = 𝑀2𝑉2
𝑀1
V1 = 0.300 M × 0.50 L
2.00 M = 0.075 L
V1 =0.075 L × 1000 mL
1L = 75 mL
33) What volume of a 3.00M KI stock solution would you use to make 0.300L of a 1.25M KI
solution?
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34) How many milliliters of a 5.0M H2SO4 stock solution would you need to prepare 100.0mL
of 0.25M H2SO4?
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35) If 0.5L of 5M stock solution of HCl is diluted to make 2L of solution, how much HCl, in grams,
was in the solution?
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Molality (molal concentration)
Number of dissolved moles of solute in a specific mass of solvent .
(m)= 𝒎𝒐𝒍𝒆𝒔 𝒐𝒇 𝒔𝒐𝒍𝒖𝒕𝒆
𝒔𝒐𝒍𝒗𝒆𝒏𝒕 𝒎𝒂𝒔𝒔(𝒌𝒈)
36) Why do chemists prefer molality than molarity?
Because molarity changes by changing temperature, as the temperature increase the solution
volume expands so the concentration decreases.
In the lab, a student adds 4.5 g of sodium chloride (NaCl) to 100.0 g of water. Calculate the
molality of the solution.
solute mass = 4.5g NaCl
Solvent mass = 100.0g
Molality (m) =?
4.5g NaCl × 1𝑚𝑜𝑙 𝑁𝑎𝐶𝑙
58.44 𝑔 𝑁𝑎𝐶𝑙 = 0.077 mol NaCl
(m)= 𝒎𝒐𝒍𝒆𝒔 𝒐𝒇 𝒔𝒐𝒍𝒖𝒕𝒆
𝒔𝒐𝒍𝒗𝒆𝒏𝒕 𝒎𝒂𝒔𝒔(𝒌𝒈)
100.0 g H2O × 1 𝑘𝑔
1000 𝑔 = 0.1000 kg H2O
m = 0.077 𝑚𝑜𝑙 𝑁𝑎𝐶𝑙
0.1000 𝑔 𝐻2𝑂 = 0.77 mol/kg
37) What is the molality of a solution containing 10.0 g of Na2SO4 dissolved in 1000.0 g of
water?
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38) How much (Ba(OH)2), in grams, is needed to make a 1.00m aqueous solution?
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Mole fraction
the ratio of the number of moles of solute in solution to the total number of moles of solute
and solvent.
39) Example: 100g of hydrochloric acid contains 36g HCl and 64g H2O calculate the mole
fraction of this solution .
Solute mass = 36g HCl
Solvent mass = 64g H2O n HCl = 36g HCl ×
1𝑚𝑜𝑙 HCl
36.5 𝑔 HCl = 0.99 mol HCl
nH2O = 64g H2O × 1 𝑚𝑜𝑙
18.02 𝑔 = 3.6 mol H2O
𝑋𝐻𝐶𝑙 =𝑛𝐻𝐶𝑙
nHCl + nH2O =
0.99 mol HCl
0.99 mol HCl+ 3.6 mol 𝐻2𝑂 = 0.22
𝑋H2O =nH2O
nHCl + nH2O =
3.6 mol 𝐻2𝑂
0.99 mol HCl+ 3.6 mol 𝐻2𝑂 = 0.78
To make sure that the answer is correct, the sum of the molar fraction values should equal
to (1)
0.78 + 0.22 = 1
40) What is the mole fraction of NaOH in an aqueous solution that contains 22.8% NaOH by
mass?
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41) If the mole fraction of sulfuric acid (H2SO4) in an aqueous solution is 0.325, how much
water, in grams, is in 100 mL of the solution?
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Mole fraction
𝑋𝐴 =𝑛𝐴
𝑛𝐴+ 𝑛𝐵 𝑋𝐵 =
𝑛𝐵
𝑛𝐴+ 𝑛𝐵
XA Mole fraction XB Mole fraction nA Solute moles
nB Solvent moles
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Factors Affecting Solubility
forces between particles
Attractive forces exist among the particles of all substances.
➢ Attractive forces exist between the pure solute particles.
➢ Attractive forces exist between the pure solvent particles.
➢ Attractive forces exist between the solute and solvent particles.
When mixing solute substances and solvent, there are two options,
✓ The first option is that the attraction forces between particles of solvent and solute
particles are stronger than the attraction forces between solute particles with each
other. Here the solute particles are dissolved and dispersed in the solution .
✓ The second option is that the attraction forces between the solute particles are greater
than the attraction forces between the solvent and solute particles. Here the solute
particles are not separated and remain coherent, in which case the substance does not
dissolve .
Solvation: Surrounding solute particles by solvent particles .
Hydration: Solvation in water .
“Like dissolves like” is the general rule used to determine whether the substance will dissolve
or not.
To determine whether a solvent and solute are alike, you must examine
1. The bonding and polarity of the particles.
2. The intermolecular forces among particles.
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Aqueous solutions of ionic compounds
Water molecules consist of dipoles
on oxygen atoms and hydrogen
atoms due to the electronegativity
difference between the atoms. A
partial negative charge is formed on
the oxygen atom while a partial
positive charge is formed on the
hydrogen atom .
When dissolving salt in water, water molecules accumulate in the direction of oxygen
atoms with a partial negative charge around the positively charged sodium ions and
attract them and vice versa with negative chloride ions,
The attraction forces between ions and water molecules are stronger than the attraction
forces between ions. The ions are separated from the crystal and dissolved in water .
If the attraction between the ions of the substance is greater than the attraction
between water molecules and the ions, these ions do not separate as in the case of
plaster made out of gypsum used in the manufacture of the medical trowel .
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Aqueous solutions of molecular compounds
42) How does non-polar sugar dissolve in polar water?
The sugar molecule contains many
OH groups and these groups are
polar, because of the difference in
electronegativity between hydrogen
and oxygen (we previously learned
that the molecule may be non-polar
even if some of its bonds are polar)
Hydrogen bonds are formed between water molecules and OH groups in sugar, the
attraction between water and sugar molecules is strong at these points and is greater
than the attraction between sugar molecules, so the sugar molecules break down and
dissolve in water.
Non-polar substances dissolve better in non-polar solvents.
Heat of solution
We always emphasize basic points,
We often require energy to break bonds or to break the attraction between different
molecules.
Energy is often released when bonds are formed or when two different molecules
interact.
Depending on the difference in energy the type of solution (endothermic or exothermic)
If the energy released by the attraction between the solvent molecules and the
dissolved molecules is greater than the energy absorbed by breaking the attraction
between the solvent molecules and also between the solute molecules, so the solution
will be exothermic.
The cup temperature increases when calcium chloride is dissolved in water, which
means that it is exothermic solution.
If the energy released as a result of the attraction between the solvent molecules and
the dissolved molecules is less than the absorbed by breaking the attraction between
the solvent molecules and also between the solute molecules, so the solution will be
endothermic.
The solution temperature decreases when the ammonium nitrate is dissolved in water,
which means that the solution is endothermic.
The heat of solution: The overall energy change that occurs during the solution formation
process.
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Factors Affecting solvation
Agitation
The stirring of the solution moves a larger number of solvent particles onto the solute surface,
allowing more collisions or collisions, which accelerate the dissolving process .
Surface area
There is a difference between using a sugar cube and a teaspoon of powdered sugar to dissolve
it in water, where the crushed or ground sugar dissolved faster because of increasing the
surface area exposed to the liquid .
Temperature
The rete of solvation is affected by temperature,
For example, the solvation of solids increases as the temperature of the solution
increases, because increasing the temperature leads to increased particle movement,
causing more collisions between solvent and soluble substances, increasing the chances
of contact between them and increasing their solvation .
In contrast, the solvation of the gaseous substances decreases when the temperature is
raised, because that they acquire a certain amount of energy and it is easy to convert to
gaseous state and to escape from the attraction of the liquid particles .
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Solubility
Over time, the amount of dissolved substance increases in the
solution, as the particles of the solvent collide with solute
particles, the dissolved particles collide with each other and
sometimes return to the crystal, causing crystallization .
As the solvation increases, the crystallization rate increases until
reaching equilibrium between solvation and crystallization.
Unsaturated solutions
Is a solution that contains a small amount of solute, so there is no enough collisions between
the solute particles to crystallize again, there are other opportunities in the solution of the
solute particles to be present in the solution, which can dissolve additional quantities .
Saturated solutions
When we add large amounts of solute, the solution eventually reaches the state of equilibrium,
where the amount of dissolved solute in the solution is constant. even we add more solid
solute no more dissolved, at constant pressure and temperature .
Supersaturated solutions
When heating a saturated solution, the kinetic energy of the particles increases, giving solvent
particles another opportunity to collide with solute particles and this causes dissolving of
another amount of solute, here the solution becomes supersaturated with amount of
dissolved particles greater than can be dissolved at normal temperature and pressure .
A supersaturated solution: contains more dissolved solute than a saturated solution at the
same temperature.
Dissolved Calcium chloride (CaCl2) increases
from 64g CaCl2 per 100g of water at a
temperature of 10oC to 100 g CaCl2 when the
temperature is raised to 27oC
Solubility of Some substances such as Cerium
sulphate Ce2(SO4)3 reduces with a temperature
increase .
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43) How to prepare a supersaturated solution?
1. Quantities of solute are added until the saturation is reached .
2. Add additional amount of solute and then heat the solution until the additional amount
of solute dissolves .
3. Cool the solution slowly.
44) How can the increase of solute be precipitated in supersaturated solution?
➢ Adding a small amount of solute to the solution, it precipitates very quickly around the
small added part called the seed crestal .
Silver iodide is used as a seed crestal for water vapor in the air, allowing rainfall in a process
called cloud seeding .
➢ Scratching the inner part of the container .
➢ When the supersaturated solution is undergoes a sudden shock such as stirring.
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45) There are forces of attraction between different molecules, when dissolving substance in
another one there are two possibilities, mention what is produced if,
The attraction forces between the solute
and solvent particles are smaller than
the forces of attraction between solute
particles
The attraction forces between the solute
and solvent particles are greater than the
forces of attraction between solute
particles
46) Using periodic table Select which atoms of the two elements has more electronegativity
than the other, oxygen O and hydrogen H? And mention partial charge of each.
• The largest ___________________________ partial charge ___________________________
• The smallest __________________________ partial charge ___________________________
47) When dissolving salt in water,
• Which atoms in water molecule will gather around chloride ion? ___________________________
• Which atoms in water molecule will gather around the sodium ion? ___________________________
48) With your information on dissolving salt in water, complete the following sentence with
one of the following (smaller - larger)
The attraction forces between chloride and sodium ions on one side and water on the other
side ___________________________ the forces of attraction between sodium ions and chloride ions.
49) Why does the gypsum used in making the trowel not dissolved in water? _____________________________________________________________________________________________________________________
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50) What is the type of bond that causes sugar to dissolve in water? explain. _____________________________________________________________________________________________________________________
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51) Compare the endothermic solution with the exothermic solution.
exothermic solution endothermic solution
___________________________________ ___________________________________
Energy released as a result of the
attraction between solvent and
solute molecules
___________________________________ ___________________________________ Absorbed energy due to broken
bonds between solute particles
___________________________________ ___________________________________ Example
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Solubility of gases
The higher the temperature, the higher the particle's kinetic energy, giving the gas molecules
more opportunities to escape from the liquid, thus reduces the solubility of gases as the
temperature increases .
Henry's Law
Gas solubility in liquid directly proportional to pressure at stable temperature .
Bottles of carbonated beverage are filled with carbon dioxide gas at high pressure. When the
package is opened, the pressure on the surface is reduced and the dissolved gas molecules are
released from the liquid .
Henry’s law states that at a given temperature, the solubility (S) of a gas in a liquid is directly
proportional to the pressure (P) of the gas above the liquid.
52) If 0.85 g of a gas at 4.0 atm of pressure dissolves in 1.0 L of water at 25°C, how much will
dissolve in 1.0 L of water at 1.0 atm of pressure and the same temperature?
S1 = 0.85 g/L
P1 = 4.0 atm
S2 = ?
P2 = 1.0 atm
S1
P1
=S2
P2
𝑆2 = S1 × P2
P1
𝑆2 =0.85 g
1.0 𝐿 ×
1.0 atm
4.0 atm = 0.21 g/L
Henry’s law
𝐒𝟏
𝐏𝟏=
𝐒𝟐
𝐏𝟐 S solubility
P pressure
Solubility units (g/L)
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53) If 0.55 g of a gas dissolves in 1.0 L of water at 20.0 kPa of pressure, how much will dissolve
at 110.0 kPa of pressure?
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54) A gas has a solubility of 0.66 g/L at 10.0 atm of pressure. What is the pressure on a 1.0-L
sample that contains 1.5 g of gas?
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55) The solubility of a gas at 7 atm of pressure is 0.52 g/L. How many grams of the gas would
be dissolved per 1 L if the pressure was raised to 10 atm?
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