Compounds and Chemical Bonds
Part 1
G8 Science
Chapter 8.1
Compounds and Mixtures
• Compounds – contain
two or more different
elements chemically
bonded together
• Mixtures – contain two
or more elements or
compounds not
chemically bonded
together
C8H10N4O2
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.
Most matter is a mixture of
compounds
• Almost everything is a
compound, rather than
just an element.
• Almost everything is a
mixture of compounds
Oxygen molecule
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?
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.
Chemical Formulas
• 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.
H2 O
Water
C6H12O6
Glucose
C 2 H6 O
Alcohol
NaCl
Salt
Ca3(PO4)2 Calcium phosphate
(CH3) 3COH
tertiary butyl alcohol
Carbonic Acid - H2CO3
Acetic Acid - HC2H3O2
Sodium Hydroxide - NaOH
Potassium Hydroxide - KOH
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
Molecular properties depend on
• Exact formula
– CHNOPS
– How many of each?
• Molecular structure
– What shape does it
take?
Glucose
Carbonic acid
Ethanol
Isomerism
• Same formula
• Different structure
• It is not just the
formula that matters.
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.
Activity
• Practice reading and writing chemical
formulas.
• Handout.
• Due at end of class.
• If you get done early, work on homework – do
not socialize.