Chapter 13.2
Standards:
• GLE 0807.9.4
– Distinguish among elements, compounds, and
mixtures.
• GLE 0807.9.8
– Interpret the events represented by a chemical
equation
Key concepts:
• Interpret and write simple chemical formulas
• Identify the reactants and products of a
chemical reaction.
Key Vocabulary:
•
•
•
•
Chemical formula
Chemical equation
Reactant
Product
What do you already know?
Imagine having
to write out
ten million,
one hundred
thousand, two
hundred and
three plus
two!
Now imagine
having to write
out names!
• Why do you write with numbers
(1,2,3, 10,100,203) than writing
out their names?
• In chemistry we use short-hand as
well.
• A chemical formula is a way of
writing out what happens in an
experiment
• What is H20? Or CH4
Let’s talk compound vs. element:
• Is it a compound or element?
He
Let’s talk compound vs. element:
• Is it a compound or element?
• How many atoms?
CO2
Let’s talk compound vs. element:
• Is it a compound or element?
• How many atoms?
NaClO
Let’s talk compound vs. element:
• Is it a compound or element?
• How many atoms?
Na
Let’s talk compound vs. element:
• Is it a compound or element?
• How many atoms?
(CH3)2CHOH
So remember this!
Bonding
Ionic
Metal and nonmetal
Covalent
Charges have to
cancel out when
making the
compound!
Non-metal bond
to non-metal
Sharing until the
outer ring is full!
Chemical Formula:
What does
shorthand
mean?
How many
atoms?
-H20
-C6H1206
-CH4
• A chemical formula is a shorthand
way to use chemical symbols and
numbers to represent a substance.
– Also shows how many atoms are in
each kind of molecule
• Important parts:
– Elements symbol
– Subscripts
– Coefficients
Chemical Formula continued:
What does
shorthand
mean?
How many
atoms?
-H20
-C6H1206
-CH4
Read page 339
• Important parts:
– Elements symbol—you know this
already!
– Subscripts
• Number written below and to the right
of the symbol
• Stands for the number of atoms of that
type of element
– O2
– CO2
– N2O
Chemical Reaction:
Think of this a
piece of sheet
music...
Cheat sheet
time!
Reactants
point to
products
RP
• Chemical equation uses symbols
and formulas to describe a
chemical reaction.
• Parts:
– Reactants—starting materials
– Products—what you make
– Yield—this is the arrow sign
• This usually means that energy is going
in or out
Identify the part:
• Is it a reactant or product?
• How did you know?
H2O(l) + SO2(g)  H2SO3(g)
Identify the part:
• Is it a reactant or product?
• How did you know?
2NO2+ H2O  HNO3+
How many oxygens on this
side?
Identify the part:
• Is it a reactant or product?
• How did you know?
NaHCO3 + CH3COOH CH3COO-Na+ + H2O + CO2
Identify the part:
• Is it a reactant or product?
• How did you know?
C3H8 + 5 O2  3 CO2 + 4 H2O
Pearls of Wisdom:
• On your small sheet of paper, please list what
you learned today.
• Do you think you can tell me what I wanted
you to learn?
Homework:
• Have a great weekend!
Pancakes!