61
9/26/11
Counting Atoms
10/15/2013
Starter:
How many elements are
. in the following
compounds:
H2O, NaCl, Cl2
Practice:
Subscript
Coefficients
1.
1.
2.
2.
3.
3.
example
example
Counting Atoms
62
10/15/2013
Application
How many atoms
1.
2.
3.
4.
5.
Connection:
Counting Atoms Ws
Exit:
How does a chemical formula help
us know what atoms are in a
compound? Explain in 2-3 complete
sentences.
October 15, 2013
AGENDA
8.5 D.
I will be able to recognize
that chemical formulas
identify substances and
used to determine the
number of atoms of each
element in chemical
formulas by reading, and
writing while completing
notes and activity
1 Starter
2. Notes
3. Activity
4. Exit
NaCl
C2H4O2
Table of Contents
Date
9/25
9/26
9/27
9/30
10/1
10/2
10/3
10/8
10/9
10/10
10/15
Lecture/ Activity/ Lab
Metal, Nonmetals, and Metalloids
Where’s Al?
Element Wanted Poster
Bohr Model Challenge
Periodic Table Notes/Puzzles
Periodic Table Chart
Test Review
Test Corrections
Molecules, Compounds, and Elements
Build a Molecule Activity
Counting Atoms
Page
41-42
43-44
45-46
47-48
49-50
51-52
53-54
55-56
57-58
59-60
61-62
Coefficients and
Subscripts
6H2O + 6CO2
Water + Carbon Dioxide
C6H12O6+ 6O2
Sugar + Oxygen
Why Do We Use Chemical Formulas
and Equations?
Scientists use equations to show:
 how a chemical reaction took
place
what elements were involved
what was produced from the
reaction
Subscripts
• small numbers behind the element
symbol
• Show how atoms of an element
there are.
6H2O + 6CO2
2 hydrogen atoms
C6H12O6+ 6O2
6 carbon atoms
Subscripts
• Subscripts show the number
of atoms
H2
H4
H3
Coefficients
• are added to the front of a formula
• show how many molecules of the
compound there are
6 water molecules
6H2O + 6CO2
6 Oxygen molecules
C6H12O6+ 6O2
Coefficients
Coefficients show the
number of molecules.
4H2O
3H2O
2H2O
How Many Atoms?
• NaCl
1 sodium
• Fe2O3
2 Iron
1 chlorine
3 oxygen
2
5
How Many Atoms?
• H3 PO4
3 hydrogen
1 phosphorus
4 oxygen
• NaC2H3O3
1 sodium
2 carbon
3 hydrogen
3 oxygen
8
9
How Many Atoms?
• (CH3)2 CO
3 Carbon
6 Hydrogen
1 Oxygen
10
Add on back of sheet
H2SO4
Ca(PO4)2
HCl
CaCO3
C2H4O2
61
9/26/11
Counting Atoms
10/15/2013
Starter:
How many elements are
. in the following
compounds:
H2O, NaCl, Cl2
Practice:
Subscript
Coefficients
1.
1.
2.
2.
3.
3.
example
example
Counting Atoms
Application
How many atoms
1.
2.
3.
4.
5.
Connection:
62
10/15/2013
Counting Atoms Ws
Exit:
How does a chemical formula help
us know what atoms are in a
compound? Explain in 2-3 complete
sentences.