1. Chemistry
Water, Acids and Bases

2. Inorganic Chemistry
The study of inorganic compounds
water
acids
bases

3. Water Chemical formula H2O Properties cohesive, form H bonds
adhesive, clings to surfaces
Polar

4. Cohesion and Adhesion among water molecules plays a key role in the
transport of water against
gravity in plants
clinging of one substance to
another, contributes too, as
water adheres to the wall of
the vessels.
sequoias
wood cut

5. Surface Tension
a measure of the force necessary to stretch or break the surface of a liquid, is related to cohesion.
Water has a greater surface tension than most other liquids
Water behaves as if covered by an invisible film.
Some animals can stand, walk, or run on water without breaking the surface.

6. Polarity of Water The molecule has opposite charges on opposite sides
polar molecules form H bonds with other polar molecules

7. Water is the Solvent of Life
solution = solvent + solute(s)
ex: cup of coffee
(hot water, sugar, coffee grounds)
Aqueous solution
solvent is water
ramsey.k12.nj.us

8. Water Forms Hydrogen Bonds With Ions
the Na+ cations form hydrogen bonds with partial negative oxygen regions of water molecules.
the Cl- anions form hydrogen bonds with the partial positive hydrogen regions of water molecules.
hydration shell - each
dissolved ion is surrounded
by a sphere of water
molecules

9. Polar molecules are also soluble in water Even large molecules, like proteins, can dissolve in water if they have ionic and polar regions

10. Hydrophilic any substance that has an affinity for water
Some are water-soluble
water molecules are attracted to molecules with an electrical charge (ionic or polar bonds)
H-bond formation may form

11. Hydrophobic Substances that have no affinity for water water-insoluble
Non-ionic & nonpolar compounds are repelled by water
water-insoluble
Hydrophobic molecules are major ingredients of cell membranes
Some vegetables and fruits with nonpolar pesticides

12. Mole concept
Counting individual or even collections of molecules is not practical.
Instead, we can use the concept of a mole to convert weight of a substance to the number of molecules in that substance and vice versa

13. Mole (mol)
is equal in number to the molecular weight of a substance, but upscaled from daltons to grams
Ex. a mole of sucrose (C12H22O11)
C = 12 daltons x 12
H = 1 dalton x 22
O = 16 daltons x 11
Sucrose molecular weight = 342 daltons
one mole of sucrose = 342 g

14. Avogradro’s number The actual number of molecules in a mole,
6.023 x 1023
A mole of sucrose
contains x 1023 molecules
weighs 342g

15. Molarity the concentration of a material in solution
one molar solution
has one mole of a substance dissolved in one liter of solvent, typically water.
to make a 1 molar (1 M) solution of sucrose
add water to 342 g of sucrose until the total volume was 1 liter and all the sugar was dissolved

16. Ionization of Water 2 H2O H3O+ + OH- by convention: H2O H+ + OH-
pH of pure water is 7 (10-7 M) + - +
hydronium hydroxide

17. pH Scale 0-14 logarithmic scale pH = - log10 [H+] pure water at RT:
acid pH< 7
base pH>7
neutral pH = 7
pure water at RT:
pH = -log 10-7M
= -(-7)
= 7

18. Neutral Solution
In a neutral solution [H+] = [OH-] = 10-7 M, and the pH = 7.
Values for pH decline as [H+] increase.
While the pH scale is based on [H+], values for [OH-] can be easily calculated from the product relationship
[H+] + [OH-] = 14

19. Acids substances that increase [H+] in solution pH below 7
ex: HCl H+ + Cl -
acid precipitation, with pH < 5.6
acid indigestion use antacids

20. Bases substances that reduce [H+] in solution pH above 7
NH H NH4 +
NaOH Na+ + OH-
ammonia
ammonium ion
sodium hydroxide
sodium hydroxyde
ion ion

21. Buffer prevent sudden pH changes in biological fluids
accept hydrogen ions from the solution when they are in excess and donate hydrogen ions when they have been depleted
H2CO3 HCO H+
carbonic acid bicarbonate ion hydrogen
(donor of H+) (receptor of H+) (ion)
The End