1. Properties of Solutions

2. A Solution is A homogeneous mixture
The substances in the mixture are in the same physical state (solid, liquid, or gas)

3. Gas solution… Air is a homogeneous solution of different gases:
Nitrogen, oxygen, water vapor, carbon dioxide….etc.

4. Solid Solution
Metals are often mixed together to form a solid solution called an ALLOY
Brass is a solid solution of zinc and copper

5. Liquid Solution
Most of the solutions in Chemistry are in the liquid phase
Most common solution is a solid substance dissolved in a liquid

6. Liquid Solution = solvent + solute
Solute is the solid (present in small amounts)
Solvent is the liquid (present in large amounts)
When the 2 are mixed, the final result is a solution

7. Liquid Solution = solvent + solute

8. Solvents
The most common solvent is water. It is often called the Universal Solvent. Many (but not all!) substances will dissolve in water
Can you think of a substance that does NOT dissolve in water?

9. Aqueous Solutions
A solution made with water as the solvent is called an aqueous solution (aq)
NaCl (s) Na+ (aq) + Cl- (aq)
A salt water solution

10. Solvents
There are solvents other than water. These are often used to dissolve substances that do not dissolve in water.
Can you think of a type of solvent besides water?

11. What do liquid solutions look like?
homogeneous mixtures
Clear, not cloudy
May have color
The solute does not settle to the bottom
Pass through filters

12. Are these solutions?

13. Are these solutions?

14. Solubility Substances that dissolve easily are called SOLUBLE
Salt is soluble in water

15. Solubility Substances that do not dissolve easily are called insoluble
Nickel is insoluble in water

16. Factors that influence solubility
Why are some substances soluble in water, but not in other liquids?
Why are some substances not soluble in water?
What can be done to make a substance dissolve more easily?
It helps to understand what controls solubility….

17. Factors that influence solubility
#1 TEMPERATURE
As temperature increases, most solids become more soluble in water.
Ex. Sugar in ice tea vs. hot tea

18. Factors that influence solubility
#1 TEMPERATURE
As temperature increases, most gases become less soluble in water.
Ex. The carbon dioxide (fizz) in cold soda vs. hot soda

19. Factors that influence solubility
#2 Pressure
As pressure increases, most gases become more soluble in water.
Ex. The carbon dioxide (fizz) in soda in a pressurized can vs. soda that has been left open (goes “flat” at low pressure)

20. Factors that influence solubility
#2 Pressure
PRESSURE HAS NO EFFECT ON LIQUID OR SOLID SOLUTES!!!

21. Factors that influence solubility
#3 The Nature of the solute and solvent
where “like” refers to the polarity of the molecule
Like dissolves Like

22. Factors that influence solubility
#3 The Nature of the solute and solvent
POLAR solvents dissolve POLAR solutes
(Polar includes ionic compounds)
“Like dissolves Like”

23. Factors that influence solubility
#3 The Nature of the solute and solvent
POLAR solvents dissolve POLAR solutes
So ionic NaCl will dissolve in polar water
Like dissolves Like”

24. What is going on at the molecular level when a polar substance dissolves?
Cl-
The polar water molecule
pulls apart the ionic
compound into anions and
cations
If you evaporate away the
water, the Na and Cl will
join together again to make
NaCl (s)

25. attraction between the positive end of the water
Na+
Cl-
For this to happen, the
attraction between the
positive end of the water
molecule and the negative
ion must be STRONGER
than the attraction between
the positive and negative
ion.

27. Factors that influence solubility
#3 The Nature of the solute and solvent
NON POLAR solvents dissolve
NON POLAR solutes
Non polar solvents and solutes simply mix together
“Like dissolves Like”

28. Factors that influence solubility
#3 The Nature of the solute and solvent
fats and oil are non polar
Oil (non polar) will not dissolve
in water (polar)
“Like dissolves Like”

29. Soaps
Soaps are long molecules that have a polar end and a non polar end
Grease (non polar) does not dissolve in water alone (polar), but if soap is added, the grease will dissolve in the non polar end of the soap. The polar end of the soap allows it to dissolve in the water, washing away the grease