1. Compounds and Chemical Bonds Part 1
G8 Science
Chapter 8.1

2. Compounds and Mixtures
Caffeine
Compounds – contain two or more different elements chemically bonded together
Mixtures – contain two or more elements or compounds not chemically bonded together
C8H10N4O2

3. Your Turn List 2 compounds. List 2 mixtures.
Discuss with your partner(s) why you think these are compounds or mixtures.
Share with the class.

4. Most matter is a mixture of compounds
Oxygen molecule
Almost everything is a compound, rather than just an element.
Almost everything is a mixture of compounds

5. Chemical Bonds
Chemical bonds form when atoms transfer or share electrons.
May transfer or share one or more electrons.
The atoms are chemically bonded and moves together.
What element is this?

6. Covalent Bonds Covalent bonds are formed when atoms share electrons.
Single Bond
Double Bond
Triple Bond
Atoms held together with covalent bonds are called molecules.
Covalent bonds are formed between nonmetals and nonmetals.
They both have to share!
The shared electrons belong to both of them.

7. Chemical Formulas
H2O
Water
C6H12O6
Glucose
C2H6O
Alcohol
 NaCl
Salt
Chemical formulas tell many of what kind of atoms are in the molecule.
Atomic symbol.
Subscript is count of that element.
Parenthesis breaks up repeating units.
Hint of the structure.
Ca3(PO4)2 Calcium phosphate
(CH3) 3COH tertiary butyl alcohol
Carbonic Acid - H2CO Acetic Acid - HC2H3O2
Sodium Hydroxide - NaOH Potassium Hydroxide - KOH

8. Chemical Structure Chemical structure is important to function.
Shows shape and arrangement of atoms.
Shows single, double, and triple bonds.
Sometimes 3D structures are used.
Benzene
Acetic acid

9. Molecular properties depend on
Exact formula
CHNOPS
How many of each?
Molecular structure
What shape does it take?
Glucose
Carbonic acid
Ethanol

10. Isomerism Same formula Different structure
It is not just the formula that matters.

11. Your Turn
Write down an analogy – two thinks that are made of the same substance but are shaped differently and, therefore, have different uses.
Discuss your analogy with your partner(s).
Share your analogy with the class.

12. Activity Practice reading and writing chemical formulas. Handout.
Due at end of class.
If you get done early, work on homework – do not socialize.