1. Solutions
Solution Solvation
Solute + Solvent
Solutes:
Can be solid, liquid, or gas
Solvent:
Liquid

2. Temperature and
Solubility
Increased temperature usually increases the
solubility of a solute in a solvent
...But not always
Exceptions: NaCl and CsCl

3. Temperature and
Solubility of Gases
Inverse
relationship
Why do Brook
trout like cold
water?

4. What about pressure and
solubility?
Has no effect on solubility of
solid and liquid solutes
Gases are different
Henry’s Law: Solubility is
directly proportional to
pressure
SCUBA diving and “the
bends”

5. Solvents: “Like Dissolves
Like”
Properties of solvents- “Like dissolves like”
•
Solvents are either polar or non-polar
•
CH3-CH2-CH2-CH2-CH2-CH3 (Hexane, a non-polar solvent)
•
H2O (water, a polar solvent)
•
Hexane will dissolve oils, greases, Styrofoam
•
Water will dissolve ionic substances like NaCl or polar liquids like alcohol
•
Hexane and water are immiscible

6. How do soaps work?
Soaps were originally made
from animal fat and ashes
Hydrophobic end dissolves oils
Hydrophilic end is attracted to
water
The result: clean clothes

7. Micelles: collections of
soap molecules

8. Solutions and Dilutions
How do you make 1.0 liter of a 0.1M
NaOH solution?
NaOH weighs 40.0 grams/mole
A 0.1M solution contains 0.1 mole of
solute per 1.0 liter of solution
Take 4.0 grams of NaOH, put it in a 1.0
liter volumetric flask, fill with water to
the line
Volumetric Flasks

9. Dilutions: How do you make a
dilute solution from a stock
solution?
How do you make 50.0 ml of a 0.25M NaOH
solution from a 1.0M solution?
Mc x Vc = Md x Vd
1.0M x Vc = 0.25M x 50.0 ml
Vc= 12.5 ml of 1.0M NaOH;
take this and add it to 37.5 ml of water

10. Titrations: Using a solution of known
concentration to find the concentration of an
unknown solution
Usually done to find the
concentration of an
unknown acid or base
Neutralization reaction
Indicator dye is used to
show ‘endpoint’ Performing a titration
Ma x Va = Mb x Vb

11. A Sample Titration...
What is the concentration of 25.0 ml of HCl if it
takes 75 ml of 0.1M NaOH to reach a ‘pink’
endpoint?
Ma x 25.0 ml = 0.1M x 75 ml
Ma = 0.3M; this is the concentration of the HCl

12. Freezing Point
Depression
When solutes dissolve in solvents the freezing
point of the solvent is lowered
The boiling point is elevated
Are there biological applications to this?

13. Hibernation and Survival
in Cold Climates
Wood Frog
Tfp = (1.86)(#Particles)(Moles solute)
Kg Solvent