Transcript Day Two Ppt
Unit: Chemical
Reactions
Balancing chemical equations
After today you will be able to…
• Explain the Law of Conservation of
Atoms
• Balance equations using the “tally
method”
Law of Conservation of Atoms:
There must be the same
number of each type of atom
before the reaction as after
the reaction.
Coefficients: Are numbers
that go in front of each
substance to indicate the
number of atoms or molecules
that are reacting or being
produced.
Let’s try some
examples!
We will be using the “tally
method” to balance equations
in this class.
Examples: Balance the following equation:
2 Al + ___S
3
___
___Al2S3
2 1 Al 2
3 1 S 3
If the numbers match on
either side… You’re balanced!
Examples: Balance the following equation:
42 Li + ___O ___Li
2
___
2
2O
4 2 1 Li 2 4
2 O 1 2
Examples: Balance the following equation:
3
2
2
___Fe2(SO4)3 + ___Na
3(PO4) ___Fe(PO4) + ___Na2(SO4)
2 Fe 1 2
3 (SO4) 1 3
6 3 Na 2 6
2 1 (PO4) 1 2
Helpful tip:
Do not separate
Are
we
balanced?
YES!!!!
polyatomic ions!
Do now: Complete
“Exit Ticket”
Then: Begin WS 2
(Homework)