1. Mixtures and Solutions
Solute and Solvent

2. Matter Homogeneous mixtures Pure substances Solution
Heterogeneous materials - can see two parts
Homogeneous materials can see only one thing - one set of properties
Mechanical Mixture
Homogeneous mixtures
They’re mixed together so well you only see one thing – it looks pure but it isn’t
Pure substances
You can only see one thing because there is only one kind of particle in it.
Solution

3. Review Solutions Are solutions homogeneous or heterogeneous?
Are solutions mixtures or pure substances?
Mixtures
What kind of states can a solution be?
Solid, liquid, or gas
What are the two “s” words that every solution must have?
A solute and a solvent

4. In a salt water solution…
Is salt the solute or the solvent?
Solute
Is water the solute or the solvent?
Solvent
What does the solute do?
Gets dissolved
What does the solvent do?
Does the dissolving

5. A Salt Water Solution
Solute (salt)
Animation
Solvent (water)

6. Dissolving

7. Solution Worksheet solute solute solute solute solute solute solute
solvent
solvent
solvent
solvent
solvent
solvent
solvent
solvent

8. Solution Worksheet SOLUTION solute solute solute solute solute solute
8. Minerals Water Hard Water
9. Water Sugar Maple Syrup
10. Acetic Acid Water Vinegar
11. Salt Water Ocean Water
12. Zinc Copper Brass
13. Water Air Humid Air
solute
solute
solute
solute
solute
solute
solute
solute
Solution Worksheet
solvent
solvent
solvent
solvent
solvent
solvent
solvent
solvent

9. Comparison of Solutions, Colloids, and Suspensions
< 1 nm
> 100 nm
solutions
colloids
suspensions
-single atoms
-small molecules
-ions
-polyatomic ions
-aggregates of atoms, molecules or ions
-macromolecules (proteins)
-clumps of particles,
-mineral grains such as sand

10. More Comparison… solutions colloids suspensions < 1 nm > 100 nm
transparent
(clear)
transparent with Tyndall effect
translucent
(cloudy)
Brownian motion- colloidal particles moved by solvent
molecular motion
movement by gravity
never settle
coagulation – can settle

11. Light passage… solutions colloids suspensions < 1 nm > 100 nm
Absorption of light
Scattering in
all directions
Passage of light
Scattering in beam

12. Using whole blood as an example…
< 1 nm
> 100 nm
solutions
colloids
suspensions
-dissolved in water
electrolytes (salts)
gases
glucose
-plasma proteins
albumins
globulins
fibrinogen
-cellular stuff
red blood cells
white blood cells
platelets

13. Solutions: homogeneous mixtures
Absence of settling
Two components (at the least)-
Solute – the substance being dissolved
Solvent – the dissolving medium
usually water – aqueous solution
can have multi-solute solutions - seawater

14. Types of solutes Strong Electrolyte - 100% dissociation,
high conductivity
Strong Electrolyte -
100% dissociation,
all ions in solution
Na+
Cl-

15. Types of solutes Weak Electrolyte - partial dissociation,
slight conductivity
Weak Electrolyte -
partial dissociation,
molecules and ions in solution
CH3COOH
CH3COO- H+

16. Types of solutes Non-electrolyte - No dissociation,
no conductivity
Non-electrolyte -
No dissociation,
all molecules in solution
sugar

17. Solubility of Solutes in Water
Most solids
(endothermic
hydration)
All gases
Solubility, g/100 mL water
Some solids
(exothermic
hydration)
Temperature

18. Dissolving process in water
2. Hydration of solute
Orientation of water molecules around solute
Na+
Cl-
1. Overcome attractive forces in solid
Click here for Chime structure

19. Types of attractive forces
For water: dipole-dipole
For hydrated ion:
ion-dipole
Na+
Cl-
For NaCl (s): ion-ion

20. How do I get sugar to dissolve faster in my iced tea?
Stir, and stir, and stir
Fresh solvent contact and interaction with solute
Add sugar to warm tea then add ice
Faster rate of dissolution at higher temperature
Grind the sugar to a powder
Greater surface area, more solute-solvent interaction

21. Units of Concentrations
amount of solute per amount of solvent or solution
g solute
g solution
x 100
g solute
g solute + g solvent
x 100 =
Percent (by mass) =
moles of solute
volume in liters of solution
Molarity (M) =
moles = M x VL

22. Examples What is the percent of KCl if 15 g KCl are
placed in 75 g water?
%KCl = 15g x 100/(15 g + 75 g) = 17%
What is the molarity of the KCl if 90 mL of
solution are formed?
mole KCl = 15 g x (1 mole/74.5 g) = 0.20 mole
molarity = 0.20 mole/0.090L = 2.2 M KCl

23. SOLUBILITY CURVES

24. WHAT DO THESE GRAPHS MEAN?
Each line shows how much stuff (CALLED SOLUTE) can be dissolved in 100 mL OF WATER (CALLED SOLVENT) at a bunch of different temperatures.
Why at a bunch of different temperatures?

25. WHAT DOES THE LINES REPRESENT?
They represents SATURATED SOLUTIONS at a given temperature:
SATURATED = cannot dissolve any more solute

26. WHAT DO THE LINES REPRESENT? continued
For example, let’s say I put a 10 grams of powdered lemonade mix into a 100 ml glass of water, and stir until dissolved
I then try to add 1 more gram, but it won’t dissolve – it just piles up on the bottom of the glass.
This shows me that at a water temperature of 20o celcius, 100 mL of water is saturated by 10 grams of lemonade mix – it cannot dissolve 11 grams (or more) of mix

27. I will plot this information on a graph – my point will be: x = 20o celcius, y = 10 grams of solute.

28. Next, I heated 100 mL of water up to 40o celcius, and I added 20 grams of powdered lemonade mix into the heated glass of water, and I stirred until it all dissolved I then try to add 1 more gram, but it won’t dissolve – it just piles up on the bottom of the glass.

29. This shows me that at a water temperature of 40o celcius, 100 mL of water is SATURATED by 20 grams of lemonade mix – it cannot dissolve 21 grams (or more) of mix

30. I will plot this information on a graph – my point will be: x = 40o celcius, y = 20 grams of solute.

31. This is a SATURATION curve – it’s a line that shows how much lemonade mix (the SOLUTE) saturates 100 mL of water at different temperatures (so far, I’ve tried 2 temperatures)

32. Next, I continued to heat 100 mL of water up by 10o celcius, and I kept adding grams of powdered lemonade mix into the heated glass of water, and I stirred until it all dissolved.

33. For each new temperature, I would then try to add 1 more gram, but it won’t dissolve – it just piles up on the bottom of the glass. At that point, I’d heat up the water again, and repeat the process…..

34. I then plotted all this information on my graph – with x points for every 10o celcius, and y points for the grams of solute that would completely dissolve at that water temperature:

35. I now have a SOLUBILITY CURVE for Lemonade mix :
The LINE ITSELF represents a SATURATED SOLUTION, which is the maximum mass of solute dissolved in 100 mL of water at a given temperature:

36. Remember, water becomes a better solvent as it is heated, so it can dissolve more solute at higher temperatures – that’s why the curve has a positive slope:

37. The LINE ITSELF also represents a “perfect” SOLUTION; that is, a solution with the EXACT amount of solute that will saturate 100 mL of water:

38. (points below the line )
At any temperature, any LESS solute than the value on the line would produce an UNSATURATED solution
(points below the line )
If 5 grams of mix were added to 40o water, the solution would not be saturated, as shown by the point BELOW the saturation line

39. (points above the line)
At any temperature, any MORE solute than the value on the line would produce an OVERSATURATED solution
(points above the line)
If 70 grams of mix were added to 100o water, the solution would be more than saturated, as shown by the point ABOVE the saturation line

40. Any mass of solute BELOW the curve
Any mass of solute ABOVE the saturation/solubility curve would
OVERSATURATE
the solution
Any mass of solute BELOW the curve
would UNDERSATURATE
the solution

41. More solute can be dissolved to make the solution saturated
UNDISSOLVED SOLUTE AT BOTTOM, or PRECIPITATE
forms as
the solution cools
More solute can be dissolved to make the solution saturated

42. Vocabulary Dissociating = to break apart ions
NaCl + H2O = Na+ separates from the Cl- and each are surrounded by water molecules
Dissolving = to break apart molecules
Sugar + H2O = molecules of sugar separate in water
Ionizing = another term for Dissociation

43. Non electrolytes do not conduct electricity when dissolved in water.
Polar covalent molecules such as methanol CH3OH don’t fall apart into ions when they dissolve.
Weak electrolytes don’t fall completely apart into ions.
Strong electrolytes do ionizes completely.

44. Solutions are composed of:
Solvent = does the dissolving; always in the greater concentration
Solute = is dissolved; always in lesser concentration
solvent concentration > solute concentration
Ex. 5g of NaCl + 1 Liter of water:
Solvent =
Solute =

45. Types of Solutions:
Saturated Solution: undissolved solute is in equilibrium with the dissolved solute
Unsaturated Solution: contains less than the saturated amt. of solute for that temperature
Supersaturated Solution: contains more solute than a saturated solution can normally hold.

46. Who will dissolve me?
“Like dissolves like” = polar solvent will dissolve polar solute or nonpolar solvent will dissolve nonpolar solute.
Ex. Salt will dissolve in water but not acetone.
Ex. Oil will not mix with water
Miscibility - the ability of two liquids to be mixed.
Oil is immiscible in water
Vinegar is miscible in water

47. Rate of Solution Affected By:
Surface area of solid exposed to solvent.
Increase SA, increase solution rate
Stirring of solution
Stirring the solution will prevent buildup of saturated solution around solute
Kinetic Energy (motion) of solute and solvent
Increase T = increase KE = Increase solution rate

48. Solubility
The maximum mass of a substance that will dissolve in 100g of water at a given temp.
Use solubility chart to determine.
EX: 40g of NaCl dissolves in 100g of water at 80oC.

49. Solubility Curve
A solubility curve shows the maximum mass of solute that will dissolve in 100g of water from 0oC-100oC.

50. Types of Solutions
Saturated Solution: undissolved solute is in equilibrium with the dissolved solute (on the line)
Unsaturated Solution: contains less than the saturated amt. of solute for that temperature (below the line)
Supersaturated Solution: contains more solvent than a saturated solution can normally hold. (above the line)

51. 5. Describe an unsaturated solution of potassium chlorate.
1. How many grams of potassium iodide can be dissolved in 100g of water at 700C?
2. 100g of sodium nitrate in 100g of water at 50oC is a(n) _______ solution.
g of sodium nitrate in 100g of water at 80oC is a(n) _______ solution.
4. How many grams of potassium nitrate make a saturated solution at 70oC?
5. Describe an unsaturated solution of potassium chlorate.