1. Chemistry of Life Chemical formulas show how atoms combine
Elements and Compounds
Element- a substance with only one type of atom. (gold, silver, oxygen)
Compound- a substance with more than one type of atom. A molecule is the smallest part of a compound. (water, glucose)
Empirical Formula- expresses the composition of atoms in a molecule in the lowest terms.
H2O
NaCl
CH2O

2. Chemistry of Life
Molecular Formulas- shows the composition of atoms in a molecule in exact terms.
C6H12O6
C3H6O C8H16O8
H2O
CH pair of shared electrons
Structural Formulas- shows
the actual structure of a
molecule, each line in the
model representing a pair
of shared electrons.

3. Chemistry of Life The Atom and its Arrangement. 0- neutron + proton
- electron

4. Chemistry of Life
Radioisotopes- An isotope is an atom of the same element that has a different number of neutron. A radioisotope is a radioactive isotope that can be used as a tracer in medicine or to find the route of atoms in a biochemical pathway. After taking a radioisotope

5. Chemistry of Life Types of Bonds
Ionic Bonds- transfer of electrons to a recipient from a donor. Bond is due to the attraction of oppositely charged atoms.
Covalent Bonds- electrons are shared by 2 atoms making the bond very strong.

7. Chemistry of Life Acids, Bases and Salts! Acids- Characteristics-
Contain hydrogen covalently bonded to another group or single atom
When compounds dissolve H+ is dissociated. The rest forms a negative ion.
Sour taste
Ex. HCl, H2SO4
HCl H Cl-

8. Chemistry of Life Bases-Characteristics-
Contain hydroxyl ions (OH-) in an ionic state
When compounds dissolve in water, the OH- is dissociated, the rest forms a positive ion.
Slippery in touch
Ex. NaOH, NH3
NaOH Na+ + OH-
NH3 + H2O NH4 + + OH-

9. Chemistry of Life Salts- Characteristics- Acid + Base Salt + Water
Ex. CaOH + HCl CaCl + H2O
Ex. NaOH + HCl NaCl + H2O
Dissociation of Water
Water is neutral even though:
H2O H+ + OH in small proportions
Why???????

10. Chemistry of Life pH Scale (percent Hydrogen)
In acids- there is more H+
than in H2O
In bases there is less H+
Each number on the scale
means a change of 10x.
pH of 3 is 100x more acidic
than a pH of 5

11. Chemistry of Life
pH Indicators show a color change when pH goes above or below a certain level. pH must be just right for a chemical reaction to occur
Phenolphthalein- colorless to red in pH above 10
Litmus paper turns red when pH is below 5
and blue when pH is above 8.
Methyl orange- yellow to red in pH below 3.
pH paper- more specific Paper changes color- compare to color chart on container

12. Chemistry of Life Organic Compounds versus Inorganic Compounds
Organic compounds are carbon compounds that almost always contain hydrogen.
Found naturally occurring in living things.
Ex. Carbohydrates, Lipids, Proteins, Nucleic Acids
Inorganic Compounds- do not contain carbon (there are exceptions)
Ex. Water, acids, bases and salts