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Solutions
A solution is made up of a solute dissolved in another substance called a solvent.
Salt:
the solute
Water:
the solvent
Ex: Salt Water
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2. Concentration
Depending on how much solute we put in the solvent, the concentration of the solution will vary.
Concentration of a solution
the quantity of solute dissolved in a given quantity of solution

3. Concentration (molecules)
200mL 200mL 100mL

4. Concentration
200mL 200mL 100mL

5. Concentration C (g/L) Ratio of solute to solution
Ex: Concecntration of 7g
of solute in 1 L of solution
would be 7g / L
(mass of solute in g)
(g/L)
(volume of solution in L)
m (grams)
V (Litres)
C (g/L)

6. Concentration
What is the concentration of the solution prepared by adding 1g of salt to 500mL of water?
Mass (grams)
Concentration (g/L)
Volume (Litres)

7. Calculating concentrations…
Concentration can be calculated in several ways…
In grams/Litre: C= masssolute in g
volumesolution in L
In milliltres/litre: C = volumesolute in mL
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8. Calculating concentrations…
Concentration can also be expressed as a percentage:
Ex: Concentration of 5% = 5g/100mL
% mass/mass = mass solute x 100
mass solution
% mass/Volume= mass solute x 100
Volume solution (ml)
% Volume/Volume = Volume solute x 100
Volume solution(ml)
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Example:
Calculate the concentration of 350 mL solution with 28 mL of acetic acid dissolved in it.
Csolution = volumesolute = 28 mL = 80 mL/L
volumesolution L
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Example (cont’d)
Find the concentration of the same solution, but in mL/100 mL
1 L = 1000 mL
80 mL = ? mL
1000 mL mL
C= 80 mL x 100 ml = 8 mL
1000 mL
The concentration of this acetic acid solution is 80 mL/L or mL/100mL
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11. Saturated vs. unsaturated
A saturated solution is a solution that has the maximum amount of solute possible dissolved in a given volume of solvent (all extra solute falls to the bottom of the beaker)
An unsaturated solution is a solution in which we can still dissolve more solute in a given amount of solvent
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Solubility
Solubility is a physical characteristic property that defines the maximum amount of solute that can be dissolved in a given amount of solvent at a specific temperature and pressure
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Insolubility
There are some molecules which are not attracted by certain solvents. For example, you can’t dissolve oil in water because oil particles are more attracted to each other than to water molecules
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Factors that affect the rate if dissolution: How can we make something dissolve faster??
Crushing the solute: increases surface area of contact with solvent
Aggitation (shaking/stirring) makes molecules move faster, leaving more space between molecules and allowing solute and solvent molecules to come into contact more quickly
Heating: particles have more energy and collide more (dissolve more)
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15. Concentrated or Dilute?
Concentrated solutions have a lot of solute dissolved in a given amount of solvent
Dilute solutions have a little solute dissolved in a given amount of solvent
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16. Dilution
Dilution is the procedure of making a final solution that is weaker (less concentrated) than the initial solution by adding more solvent to it. When dilution happens, the solute is more spread out in the solvent.
Ex:. Concentrated soups need to be mixed with one can of water.

17. Two ways to dilute a solution
1: Add solvent to a solution (adding water to frozen juice)
2: Add a concentrated solvent to a solution to obtain desired quantity (chocolate syrup in milk)
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18. Formula for dilutions C1 V1 = C2 V2
C1 = initial concentration of original solution
V1 = initial volume
C2 = final concentration of solution
V2 = final volume

19. Helpful Hints C1 is always greater than C2
V2 is always greater than V1
C units are g/L, g/mL or %
V units are mL or L (LOOK AT C units )

20. Helpful Hints
Remember the units of measure must remain the same : g=g, L=L, mL=mL
The units for both C’s must be the same
The units for both V’s must be the same
L to mL (x 1000)
mL to L (/1000)
1L = 1000 mL

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EXAMPLE
We have a solution with an initial concentration of 20 g/L. we dilute it so that its new concentration is 10 g/L and its new volume is 1000 ml. what was its initial volume?
C1V1 = C2V2
(20 g/L)(x) = (10 g/L)(1L)
x = (10 g/L)(1L)
20 g/L
x = 0.5 L or 500 mL
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22. Examples
Calculate the new concentration if enough water is added to 100mL of 25g/L sodium chloride to make up 1.5L.