1. Solutions

2. Solutions
A solution is a homogeneous mixture of 2 or more substances in a single phase.
One constituent is usually regarded as the SOLVENT and the others as SOLUTES.

3. Parts of a Solution Solution Solvent Solute
SOLUTE – the part of a solution that is being dissolved (usually the lesser amount)
SOLVENT – the part of a solution that dissolves the solute (usually the greater amount)
Solute + Solvent = Solution
Solvent
Solute
Solution

4. Nature of Solutes in Solutions
Spread evenly throughout the solution
Cannot be separated by filtration
Can be separated by evaporation
Not visible, solution appears transparent
May give a color to the solution

5. Solutions water salad soil Examples Gas in a Gas  Air
Gas in a Liquid  Soda
Liquid in a Liquid  Gasoline
Solid in a Liquid  Sea Water
Solids in Solids  Brass
Non-Examples
water
salad
soil

6. Water is the universal solvent
because more substances dissolve in water than in any other chemical.
This has to do with the polarity of each water molecule.

7. Molecular Polarity Nonpolar molecules: -- e– are shared equally
H–C–H H
Nonpolar molecules:
-- e– are shared equally
e.g.,
fats and oils
Polar molecules:
-- e– NOT shared equally H O
e.g.,
water

8. Water Molecules Are polar because O is more electronegative than H
Gives O a partial negative charge.
Form strong intermolecular hydrogen bonds.
Water molecules are attracted to one another better than other molecules its size.

9. Hydrogen bonding occurs because of polarity
animation
Hydrogen bonding occurs because of polarity
One water molecule bonds to another.

10. Surface Tension Liquid water acts like it has a skin.
Because of the hydrogen bonds, water molecules are attracted to each other.
Liquid water acts like it has a skin.
Water forms round drops.

11. Properties of Water Hydrogen bonding causes: High surface tension
Low vapor pressure
High specific heat capacity
High heat of vaporization
High boiling point
Strongest intermolecular force was hydrogen bond- review other forces
Heat capacity reflects on how fast molecules move.
Heat of vaporization- in order to evaporate you have to break the hydrogen bond- huge amount to break the bonds for vaporization temperature

12. Properties of Water
When it freezs the hydrogen bond becomes stronger- forms a hexagonal structure which takes more space

14. What is, or is not, soluble in H20?
Like Dissolves Like
“Polar solvents dissolve ionic compounds and polar molecules
Water is polar therefore it can dissolve
NaCl
Copper (II) sulfate
NaOH
Nonpolar solvents dissolve nonpolar compounds
Oil is nonpolar, which is why oil and water separate

15. Animations of the Solvation (Animation of a Solute Dissolving)
While you watch each video clip, record your observations on your notes. Animation of Salt Dissolving in Water Animation of Sugar Dissolving in Water
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Password: tiger.core

16. When Ionic Solids Dissolve
Animation H O H O

17. Aqueous Solutions
How do we know ions are present in aqueous solutions?
The solutions can conduct electricity
They are called ELECTROLYTES
HCl, MgCl2, and NaCl are strong electrolytes. They dissociate completely (or nearly so) into ions.

19. Electrolyte vs. Non-Electrolyte
Salt
(Ionic Solids)
Sugar
(Molecular Solids)
Both
Broke apart into ions
Broke apart into whole molecules
Water is
the solvent.
Was able to light the light bulb
Did not light the light bulb
Forms a
solution
an electrolyte
a non-electrolyte
Can Conduct an Electric Current
Can’t Conduct an Electric Current
An electrolyte is a substance when dissolved in water can conduct an electric current.
A non-electrolyte is a substance when dissolved in water can’t conduct an electric current.

20. Rate of Solution = How Fast
Exploration
To an empty 250mL beaker, add approximately 100mL of warm-hot water from a hot plate.
To an empty 250mL beaker, add approximately 100mL of ice water. Be sure to leave the ice behind! 
Add a sugar cube to each of the 250mL beakers. Observe what happens.
Record your observations on your notes.
List other ways that you believe that you could make a solute dissolve more quickly.

21. Electrolytes in the Body
Carry messages to and from the brain as electrical signals
Maintain cellular function with the correct concentrations electrolytes
Make your own
50-70 g sugar
One liter of warm water
Pinch of salt
200ml of sugar free fruit squash
Mix, cool and drink

22. What are ways that you make a solute dissolve faster?
Rate of Solution
What are ways that you make a solute dissolve faster?
Increase the temperature.
Crush or use smaller size solute particles.
Stir the solutions.

23. Solubility = How Much Type of Solute Temperature Pressure Solid Solute
Gaseous Solute
Solubility generally increases as temperature increases.
Pressure has no effect on the solubility of a solid.
Solubility generally decreases as temperature increases.
Solubility generally increases as pressure increases.
For gases, it may be helpful to have students think of soda. You keep soda in the refrigerator (low temps) and closed (keep pressure up).

24. Types of Solutions There are three ways to classify a solution.
Unsaturated Solutions
Saturated Solutions
Supersaturated Solutions

25. Relation to Solubility Curve
Types of Solutions
Type of Solution
Description
Picture
Relation to Solubility Curve
Unsaturated
Saturated
Supersaturated
A solution in which more solute can dissolve
Below the
Line
A solution in which contains the maximum amount of solute
On the
Line
See PDF for pictures
A solution in which contains more than the maximum amount of solute
Above the
Line

26. Supersaturated
The solution is holding more solute than it should be able to. This is achieved by heating the solution and then cooling it slowly.
Examples: rock candy, southern style sweet tea, chemical heat packs
Supersaturated solutions are unstable. The supersaturation is only temporary

27. SUPERSATURATED SOLUTION
Solubility
UNSATURATED SOLUTION
more solute dissolves
SATURATED SOLUTION
no more solute dissolves
SUPERSATURATED SOLUTION
becomes unstable, crystals form
increasing concentration

28. Supersaturated

29. Solubility Curves
Solubility indicates the amount of solute that will dissolve in a given amount of solvent at a specific temperature.
For this curve,
X-Axis
Temperature
Y-Axis
How Much Solute Dissolves in 100g of Water
Various Lines
Each line represents a different solute.

30. Solubility Curves
Supersaturated
CO2
Saturated
Unsaturated

31. Using an available solubility curve, classify as
unsaturated, saturated,
or supersaturated.
per 100 g H2O
80 g 30oC
unsaturated
45 g 60oC
saturated
30 g 30oC
supersaturated
70 g 60oC
unsaturated

32. Describe each situation below.
(A) Per 100 g H2O,
100 g 50oC.
unsaturated;
all solute dissolves;
clear solution.
(B) Cool solution (A) very
slowly to 10oC.
supersaturated;
extra solute remains
in solution; still clear
(C) Quench solution (A) in
an ice bath to 10oC.
saturated; extra solute (20 g)
can’t remain in solution and becomes visible

33. How to use a solubility graph?
A. IDENTIFYING A SUBSTANCE ( given the solubility in g/100 cm3 of water and the temperature)
Look for the intersection of the solubility and temperature.

34. Using Solubility Curves
How much KNO3 would dissolve in 100g of water at 50oC?
How much NH4Cl would dissolve in 200g of water at 70oC?
At what temperature would 22g of KCl be able to dissolve in 50g of water?
Which is more soluble (has a higher solubility) at 40oC?
NH3
KClO3
84g
120g
68oC

35. Learning Check : What substance has a solubility of 90 g/100 cm3 in water at a temperature of 25ºC ?

37. Learning Check :
What substance has a solubility of 200 g/100 cm3 of water at a temperature of 90ºC ?

39. Look for the temperature or solubility
Locate the solubility curve needed and see for a given temperature, which solubility it lines up with and visa versa.

40. Learning Check: What is the solubility of potassium nitrate at 80ºC ?

41. What is the solubility of potassium nitrate at 80ºC ?

42. Learning Check : At what temperature will sodium nitrate have a solubility of 95 g/100 cm3 ?

43. Learning Check: At what temperature will sodium nitrate have a solubility of 95 g/100 cm3 ?

44. Learning Check: At what temperature will potassium iodide have a solubility of 230 g/100 cm3 ?

45. Learning Check: At what temperature will potassium iodide have a solubility of 130 g/100 cm3 ?

46. Using Solubility Curves: What is the solubility of sodium chloride at 25ºC in 100 cm3 of water ?
From the solubility graph we see that sodium chlorides solubility is 36 g.

47. SOLUBLE OR INSOLUBLE? Soluble: able to be dissolved Insoluble:
does not dissolve in solution (or water)
Precipitate:
an insoluble solid formed when two solutions are mixed

48. Soluble compounds contain…
Insoluble compounds contain…
For these compounds, common exceptions are INSOLUBLE.
For these compounds, common exceptions are
SOLUBLE.

49. Double Replacement reactions
AB + CD  AD + CB
NaCl + AgNO3  NaNO3 + AgCl

50. Concentration of Solute
The amount of solute in a solution is given by its concentration.
Molarity ( M ) =
moles solute
liters of solution

51. Step 1: Calculate moles of NiCl2•6H2O
PROBLEM: Dissolve 5.00 g of NiCl2•6 H2O in enough water to make 250 mL of solution. Calculate the Molarity.
Known
Mass=5 g
Volume = L
Unknown
Molarity of
NiCl2•6 H2O ?
Analysis
molar mass = g
M= n/ V;
Step 1: Calculate moles of NiCl2•6H2O
Step 2: Calculate Molarity
[NiCl2•6 H2O ] = M

52. MOLARITY PROBLEM
What mass of oxalic acid, H2C2O4, is required to make 250. mL of a M solution?
Known
Volume = L
M = moles/L
Unknown
g of H2C2O4,?
Analysis
molar mass = g
M= mol/ V;
Step 1: Calculate moles of H2C2O4
( mol/L) x (0.250 L) = moles
Step 2: Convert moles to grams
mol H2C2O4 x (90.00 g/mol) = g H2C2O4
1 mol H2C2O4

53. Learning Check
How many grams of NaOH are required to prepare 400. mL of 3.0 M NaOH solution?
1) 12 g
2) 48 g
3) 300 g

54. Making Molar Solutions
…from liquids
(More accurately, from stock solutions)

55. Dilution is the procedure for preparing a less concentrated solution from a more concentrated solution.
Dilution
Add Solvent
Moles of solute
before dilution (i)
after dilution (f) =
MiVi
MfVf =
4.5

56. Making a Dilute Solution
remove
sample
moles of
solute
initial solution
same number of
moles of solute
in a larger volume
mix
Making a Dilute Solution
diluted solution
Timberlake, Chemistry 7th Edition, page 344

57. Dilution
Preparation of a desired solution by adding water to a concentrate.
Moles of solute remain the same.

58. Dilution Practice Problem
What volume of 15.8M HNO3 is required to make 250 mL of a 6.0M solution?
Known
Molarity1 = 15.8 mol/L of HNO3
Volume2 = 250 mL
Molarity2 = 6.0 mol/L of HNO3
Unknown
Volume of HNO3?
Equation
M1V1 = M2V2
Solution :
V1 = (6.0 mol/L x L) / 15.8 M = L

59. Dilution Practice Problem
If we have 1 L of 3 M HCl, what is M if we dilute acid to 6 L?
Known
Molarity1 = 3 mol/L
Volume1 = 1 L of HCl
Volume2 = 6L of HCl
Unknown
Molarity of HCl?
Equation
M1V1 = M2V2;
Solution :
M2 = (3 mol/L x 1 L) / (6 L) = 0.5 M

60. Dilution Practice Problem
What volume of 0.5 M HCl can be prepared from 1 L of
12 M HCl?
Solution :
V2 = (12 mol/L x 1 L) / (0.5 L) = 24 L
Known
Volume1 = 1 L of HCl
Molarity1 = 12 mol/L of HCl
Molarity2 = 0.5 mol/L of HCl
Unknown
Volume of HCl?
Equation
M1V1 = M2V2