1. Chapter 17 Water and Aqueous Systems
Liquid Water and Its Properties
Water Vapor and Ice
Aqueous Solutions
Heterogeneous Systems

2. Water
Make a list of everything you know about water:

3. Why is this going to hurt?

5. Ch 17.1 Liquid Water and Its Properties
The Water Molecule
Surface Properties
Specific Heat Capacity

6. The Water Molecule H2O Triatomic O-H Polar Covalent Bond
Oxygen highly electronegative, therefore acquires the slightly negative charge
Bond Angle of 105o
Dipole forces of attraction

7. Properties due to Hydrogen Bonding
High Surface Tension
Low Vapor Pressure
High Specific Heat Capacity
High Heat of Vaporization
High Boiling Point

12. Surface Tension
Molecules in a liquid are pulled in all directions due to intermolecular forces
The molecules at the top are only pulled down and to the sides, they are not pulled up.
These molecules tend to tighten up the top

13. Surfactant
A wetting agent that decreases surface tension of water, soap

16. Low Vapor Pressure
Hydrogen Bonds hold water molecules together preventing them from entering the vapor phase

18. Specific Heat Capacity
4.18J (1 cal) to raise 1g of water 1oC
High due to hydrogen bonding

19. Water in Space

20. Chapter 17.2 Water Vapor and Ice
Evaporation and Condensation
Ice

21. Evaporation
Heat of Vaporization kJ of energy is needed to convert 1g of water at 100oC to 1g of steam at 100oC (on your reference table)
How much energy in kJ is required to change 52.3g of water at 100oC to steam at 100oC?

22. Condensation
2.26kJ is given off when 1g of steam at 100oC is converted to 1g of water at 100oC
How much energy in kJ is given off to change 12.4g of steam at 100oC to water at 100oC?

23. Ice
As water cools it behave like most liquids and its density increases.
Once it cools to 4oC, it decreases in density.
Ice has about a 10% greater volume than water.
Ice has a lower density than water, therefore it floats.

24. Why does ice float?

25. Heat of Fusion
334J of energy is needed to convert 1g of ice at 0oC to 1g of water at 0oC (on your reference table)
How much energy in kJ is required to change 21.8g of ice at 0oC to water at 0oC?

26. Ch 17.3 Aqueous Solutions Solvents and Solutes The Solution Process
Electrolytes and Nonelectrolytes
Water of Hydration

27. Aqueous Solutions
Water with dissolved samples in it

28. Solvents
The dissolving medium

29. Solutes
The dissolved particles

30. Name the Solvent and Solute
Kool Aid

31. Name the Solvent and Solute
Hot Chocolate

32. Name the Solvent and Solute
Salt Water

33. Name the Solvent and Solute
Tea

34. Solution Process in Three Steps
Step 1 – Separation of solvent molecules, requires energy to break intermolecular forces (ΔH1)
Step 2 – Separation of solute molecules, requires energy to break intermolecular forces (ΔH2)
Step 3 – Solvent and Solute Molecules Mix, may be exothermic or endothermic (ΔH3)

35. Heat of Solution ΔHsoln
ΔHsoln = ΔH1 + ΔH2 + ΔH3
ΔHsoln < 0 , exothermic, solution process is favorable
ΔHsoln > 0 , endothermic, solution process is not favorable

36. Electrolytes
Compounds that conduct an electrical current in an aqueous solution or molten state
All ionic compounds are electrolytes
Barium sulfate conducts electricity in the molten state but not in the aqueous state, WHY?
Insoluble in water

37. Nonelectrolytes
Compounds that do not conduct an electrical current in an aqueous solution of molten state

38. Weak Electrolytes
When in solution, only a fraction of the solute exists as ions

39. Strong Electrolytes
When in solution, most of the solute exists as ions

40. Most Organic Compounds Glucose Glycerol
Strong Electrolytes
Weak Electrolytes
Non-Electrolytes
ACIDS(Inorganic)
HCl
HBr HI
HNO3
H2SO4
HClO4
BASES(Inorganic)
NaOH
KOH
Soluble Salts
KCl
MgSO4
KClO3
Heavy Metal Halides
HgCl2
PbCl2
Bases(Inorganic)
NH3
Acids (Organic)
Acetic Acid
Bases (Organic)
aniline
H2O
Most Organic Compounds
Glucose
Glycerol

41. Water of Hydration (Crystallization)
The water molecules that make up part of a crystal
A compound that contains water of hydration is called a hydrate

42. Copper(II) Sulfate Pentahydrate – Deep Blue Crystals

43. Ch 17.4 Heterogeneous Aqueous Systems
Suspensions
Colloids

44. Suspensions Mixtures from which particles settle out upon standing
The particles are much larger than that of a solution
Heterogeneous
Particles larger than 100nm
Can be filtered

46. Colloid
Heterogeneous mixtures containing particles that are intermediate in size between suspensions and solutions
Size between 1nm and 100nm
Glue, Jell-O, paint, smoke
Cloudy or milky in appearance when concentrated
Clear or almost clear when they are dilute

48. Tyndall Effect Scattering of visible light in all directions
Suspensions can exhibit the Tyndall Effect, solutions never do

51. Brownian Motion Chaotic movement of colloidal particles
Caused by collisions between water particles and small dispersed colloidal particles
These collisions prevent the particles from settling

52. Emulsions Colloidal dispersions of liquids in liquids
Example: Oil and water mixed together with soap