Water

1
Water

• The Common Solvent

2
Water

• What is water?
• Water is all this and more- life, industry, and
  temp control

3
Water

• Can dissolve many substances
• bent or V-shaped
• H-O-H angle of 105o

4
Water

• O-H bonds are covalent
• oxygen has greater attraction for e- than hydrogen

5
Water

• Oxygen slightly negative
• Hydrogen slightly positive
• Polar molecule-unequal charge distribution

6
Water

• Hydration- positive ends of water attracted to
  anions and negative ends attracted to cations

7
(No Transcript)
8
Water

• Hydration causes salts to fall apart
• The bonds in the solid are replaced by water-ion
  bonds

9
Water

• When ionic substances dissolve- they break up
  into individual cations and anions

10
Water

• Solubility-the amount a substance dissolves
• varies greatly in water- depends on relative
  attractions of ions

11
The Solubility Rule

• Like Dissolves Like!!
• Nonpolar substances dissolve in nonpolar
  substances and polar/ionics dissolve in polar
  substances

12
(No Transcript)
13
Solution

• Homogeneous mixture
• same throughout but composition can change

14
Solution Parts

• Solute-dissolved in a solution
• Solvent- does the dissolving

15
Electrical Conductivity

• Ability to conduct an electric current
• Strong electrolytes- can conduct electricity very
  efficiently

16
(No Transcript)
17
Electrical Conductivity

• Weak electrolyte-conduct only small current
• Nonelectrolytes-no current flow

18
(No Transcript)
19
Electrical Conductivity

• Conductivity due to presence of ions in solution-
  idea of Arrhenius!

20
Strong Electrolytes

• Completely ionize when dissolved in water
• 1. Soluable salts
• NaCl, KNO3, BaCl2

21
Strong Electrolytes

• 2. Strong Acids
• Learn these! HCl, HBr, HI, H2SO4, HClO4, HNO3
• Acid- substance that produces H ions

22
(No Transcript)
23
Strong Electrolytes

• 3. Strong Bases
• Contain OH- group
• Bitter taste and slippery feel

24
(No Transcript)
25
Weak Electrolytes

• Small ionization in water
• produce few ions when dissolved in water

26
Weak Electrolytes

• Most common are weak acids (acetic acid) and weak
  bases (ammonia)

27
Nonelectrolytes

• Substances that dissolve in water but do not
  produce any ions
• the entire molecule dissolves w/o breaking

28
(No Transcript)
29
Chemical Rxn in Soln

• Need to know
• 1. Nature of the rxn
• 2. Amounts of chemicals

30
Concentration of Soln

• Molarity (M) moles of solute per liter of
  solution

31
Molarity

• What is the molarity of a solution made by
  dissolving 10.4 g of solid NaOH to make 1.75 L of
  solution?

32
Concentration of Ions

• Give the concentration of each type of ion in the
  solns.
• 1 M NaCl
• .5 M Co(NO3)2

33
Conc of Ions 2

• Calculate the number of moles of Cl- ions in 1.5
  L of 1.5 x 10-2 M ZnCl2

34
Conc and Volume

• What volume of .15 molar AgNO3 contains 1.0 mole
  of silver?