This document provides information about chemical equations, including: 1. Chemical equations are symbolic representations of chemical reactions that are balanced and show states of matter. 2. It is important to balance chemical equations because of the law of conservation of matter, which states that matter cannot be created or destroyed in ordinary chemical processes. 3. There are different types of chemical reactions including synthesis, decomposition, single displacement, and double displacement. Solubility rules can be used to predict if a reaction will form a precipitate.

1. Chemical Equations
That’s what it’s ALL about
Grooooovey baby…yeah!!

2. What is a chemical equation?
 It is a symbolic representation of a chemical
reaction, that is balanced and represents
the states of matter
That’s soooo exciting!…yeah ok, not really

3. And I want to know this
because……
 It is good to know whether a reaction will
take your face off BEFORE you actually
throw the chemicals together

4. Still not sure I get the
concept
Think of chemical equation in the
same way that you might think of
a recipe for chocolate chip cookies.
You have ingredients, then you
prepare them, then you get cookies
Can I get my
cookies with
some Frikin’
Chocolate “chunks?”

5. Yummy!!!
Ingredients -----------> Bake ----------->Cookies
2 1/2 (1 ounce) squares unsweetened chocolate
1/2 cup butter
2 cups all-purpose flour
1/2 teaspoon baking soda
1 teaspoon baking powder
1/4 teaspoon salt
1 1/4 cups white sugar
2 eggs
1 teaspoon vanilla extract
2/3 cup sour cream
2 cups semisweet chocolate chips
--------------------->

6. It isn’t different in Chemistry…
You just don’t eat the cookies
Ingredients -----------> Bake -----------> Cookies
Chemistry:
Reactants ------------------------------> Products
Example:
O2 + H2 ----------------> H2O (+ enough energy to melt your face)
What happened to the other Oxygen????
yields

7. Law of conservation of matter
Matter can not be created nor destroyed by
ordinary chemical processes
So we have to balance the previous equation
Using coefficients OONNLLYY!!!!!!!!!!!!
O2 + H2 ----------------> H2O

8. ONCE AGAIN….
COEFFICIENTS
ONLY!!!!!!!!!

9. Here is how this equation looks
balanced:
We Must balance equations because of the law of conservation of matter
which states that matter cannot be created nor destroyed
O2 + 2H2 ----------> 2H2O

10. How do I balance an equation?
The basic concept is to use coefficients ONLY to
be sure that there are the same number of
moles of stuff on the left side as there are on
the right.
This can be done by counting single elements on
both sides and look for lowest common factors

11. This could get a bit tedious…are
there some shortcuts?
Yes:
 Look for polyatomic ions common on both sides
and treat them as one element
 Look for lowest common factors to determine
the correct coefficients
 ALWAYS double check when you are done!!!!
Anything else I need to know about equations??

12. Oh YEEEES!
 States of matter of each reactant and
product
 Reaction types and other CRAPO(N)
 Metal activity
 Nonmetal activity
 Solubility
 Endo/Exothermic

13. STATES OF MATTER OF
REACTANTS AND PRODUCTS
Since some chemicals react differently (or are
more dangerous) when they are liquids,
solids, or gasses, it is useful to determine
this ahead of time Greenhouse solids would
be a lot better than
greenhouse gasses

14. HERE ARE THE MOST COMMON
WAYS TO EXPRESS STATES OF
MATTER
 SOLID (s)
 LIQUID (l)
 GAS (g)
 AQUEOUS (DISSOLVED IN WATER) (aq)
 CRYSTALLINE (cr)
There are one or two other obscure ones but these are the
real important ones

15. Here is how they are used
O2(g) + 2H2(g) ----------------> 2H2O(l)
That is sooo clever!!!

16. THIS IS A BUNCH OF….
CRAP!!!!

17. ACTUALLY…IT’S:
C R A P O (N)
O E C R R U
M D I E G C
P O D C A L
L X B I N E
E A P I A
X S I C R
I E T
O A
N T
E
All type of reactions fall into one of these types. Nuclear is not really chemical
but it sounds funny to say crapon

18. THAT’S RIGHT….
ALL CHEMICAL REACTIONS CAN ACTUALLY
BE CLASSIFIED AS
CRAPO
(NUCLEAR IS NOT CLASSIFIED AS CHEMICAL)
THIS IS NOT THE TRADITIONAL WAY TO CLASSIFY
EQUATION TYPES….
I KNEW
IT!!

19. EQUATION (REACTION) TYPES
SYNTHESIS
 To Put Together or Produce
A + B -------> AB
Example:
H2 + O2 -----------> H2O
Can you see that this is a “putting together”
process?

20. DECOMPOSITION
TO BREAK DOWN
AB -----------> A + B
EXAMPLE:
H2O2 -----------> H2O + O2
CAN YOU SEE THAT THIS IS BREAKING
DOWN?

21. SINGLE DISPLACEMENT
(REPLACEMENT)
TO REPLACE A SINGLE ION WITH
ANOTHER
AB + C ------------> AC + B (OR CB + A)
EXAMPLE:
HCl + Mg ----------> MgCl2 + H2
Can you see that C has replaced A in the equation?

22. DOUBLE DISPLACEMENT
(REPLACEMENT)
TO SWAP TWO CATIONS OR TWO
ANIONS
AB + CD ----------> AD + CB
EXAMPLE:
NaOH + H2SO4 -------> HOH + Na2SO4
Can you see that the two cations have
switched places?

23. (ORGANIC) COMBUSTION
TO COMBUST A CARBON-BASED COMPOUND
(USUALLY HYDROCARBON) WITH O2 TO FORM CO2
AND H2O
CXHX + O2 ---------> H2O + CO2
EXAMPLE:
C2H6 + O2 ---------> H2O + CO2
CAN YOU SEE THE HYDROCARBON
REACTING WITH OXYGEN AND MAKING
CARBON DIOXIDE AND WATER?

24. From now on…
 We will refer to CRAPO(N) as Classes of
reactions
 And Synthesis, Decomposition, Single
displacement, Double displacement, and
combustion as equation types

25. ACTIVITY SERIES!!!!!
Do reactions occur every time chemicals are
put together?
Of course not…if they did we would change
every time we came in contact with another
chemical Help me!!
I’m melting

26. When a single element is reacting
with a compound
The reaction can only occur if the single
element is more active than the anion or
cation in the compound that it is replacing
Bottom line: the most active elements will be
in the bond. Find the activity chart and see
what elements are more active

27. Example
NaOH + Pb -----------> ?
Na is more active than Pb
Will Pb replace Na?

28. NO!!!!!!!!
Remember the most active elements will be
in the bond

29. Example
K + Cu(OH)2 ----------->?
K is more active than Cu
Will THIS reaction occur?

30. You Bet!!!!
K + Cu(OH)2 -----------> KOH + Cu
Now we balance it and add the states of
matter:

31. VOILA!!!
2K(s)+ Cu(OH)2(aq) ---------> 2KOH(aq) + Cu(s)

32. Do I need to memorize the activity
series?
NO: Cation activities (mostly metals) are
determined experimentally, so you will
have a chart, and anion activity series is
mostly determined by electronegativity,
and this is mainly with the Halides
(Halogens) only.

33. Activity series for metals
Li
K
Ba
Sr
Ca
Na
Mg
Al
Mn
Zn
Fe
Cd
Co
Ni
Sn
Pb
H
Cu
Ag
Hg
Au
The metals on top
Are more active
Than the
ones
Below it

34. Activity series for nonmetals
Simple: Since halides are involved in most
replacement type reactions, just remember
that the halide higher up on the periodic
table will replace the one below it, or in
other words the higher, the more active

35. SOLUBILITY
Have you noticed, in some reactions, that
solids form when you mix 2 aqueous
chemicals? How is this possible?
Easy: Sometimes chemicals form in a
reaction that don’t dissolve in water…they
are insoluble-solid

36. Solubility Definitions
Soluble: Will or is dissolved in a solvent
(usually water)
Insoluble: Will not or isn’t dissolve in a solvent
Precipitate: A solid formed from the mixing of
two aqueous liquids

37. More Definitions
Solute: A substance which is dissolved in a
solvent
Solvent: A substance which dissolves another
substance
Saturation: The formation of more soluble
product than a solution can hold at a
particular temperature and pressure

38. How do I know what makes a
precipitate?
Compounds containing the following are generally
soluble in water
1) Alkali metal ions, and ammonium ions
2) Acetate ions
3) Nitrate ions
4) Halide ions except with: Ag+
, Hg2+
, and Pb2+
5) Sulfate ions, except with: Sr2+
, Ba2+
, Pb2+

39. More Solubility Rules
COMPOUNDS WITH THE FOLLOWING ARE GENERALLY INSOLUBLE IN WATER
6) Carbonate ions (Unless any are paired with those in rule one, which
makes these soluble)
7) CrO4
2-
Chromate ions (Unless any are paired with those in rule one,
which makes these soluble)
8) Phosphate ions (Unless any are paired with those in rule one,
which makes these soluble)
9) sulfide ion (Unless any are paired with those in rule one, which
makes these soluble, as does CaS, SrS, BaS)
10) Hydroxide ions (Unless any are paired with those in rule one,
which makes these soluble, as does Ca(OH)2, Sr(OH)2, and Ba(OH)2
here)
These are all in the solubility rules table

40. PRACTICE-Write the products
and predict the precipitate
AgNO3 + NaOH ----->
NH4OH + Na2CrO4------->

41. ANSWERS
AgNO3 + NaOH -----> AgOH + NaNO3
NH4OH + Na2CrO4-----> (NH4)2CrO4 + NaOH
Blue indicates the insoluble precipitate

42. CONGRATULATIONS
YOU ARE NOW EXPERTS IN CHEMICAL
EQUATIONS!!!

43. You can use this information for
Evil…
Release the “CO2” to start
the “global Warming”

44. Or For Good…. Green is Groovey
Baby…Yeah!!!!