A2 + 3B A2B3

Balancing Equations can be fun yet tough!

This presentation will provide you some helpful tricks.

Chemical ReactionsChemical Reaction (rxn): Atom arrangement

is changed. (Bonds are formed or broken)

Chemical Equation: Shorthand notation describing what has taken place in a rxn.

Chemical ReactionsReactants: Beginning substances

Products: Ending substances

Reactants ProductsYields

Chemical ReactionsPhases of Matter:

Solid (s)

Liquid (l)

Gas (g)

Aqueous Solution (aq)

-solids dissolved in water solution

Chemical ReactionsCatalyst: Speed up a reaction, but are not used

up in the reaction & are shown above the arrow

Reactants ProductsA + B AB

Chemical ReactionsLaw of the Conservation of Matter:

Matter is not created nor destroyed, but conserved in any chemical reaction

Must have same # of elements on both sides of the reaction.

Chemical ReactionsCoefficients: Numbers placed in

front of a formula, used to balance

HgO Hg + O2

Reactants Products

2 2

Chemical Reactions

H2O(l) H2 + O2

Notice that as it stands, we have one oxygen on the reactants side and two oxygen atoms on the product

side of the equation.

2Adding a coefficient “2” in front of H2O corrects our oxygen problem, but now

causes Hydrogen to be unbalanced...

2Adding a coefficient “2” in

front of H2 corrects our unbalanced hydrogen problem.

We now have the same number of hydrogen and

oxygen atoms…It’s balanced!

Chemical Reactions

Cu + AgNO3 Cu(NO3)2 + Ag

It is helpful to list the atoms involved and find out what is balanced and what is unbalanced

(Hint = Polyatomic ions stay together!)

Reactants

Cu = 1

Ag = 1

NO3 = 1 .

Products

Cu = 1

Ag = 1

NO3 = 2 .

Unbalanced

2

2

2 Unbalanced

2

2

Chemical Reactions

F2 + H2O HF + O2

Reactants

F = 2

H = 2

O = 1 .

Products

F = 1

H = 1

O = 2 .

Try this one on your own!

Unbalanced

2

2

4 Unbalanced

4

4

4Unbalanced

2

4

Balanced!

Try this on your own and then learn a great trick

NH3 + O2 N2O4+ H2OReactants

N = 1

H = 3

O = 2 .

Products

N = 2

H = 2

O = 5 .

2

2

6 6

3

7

The only way to make 2 oxygen atoms into 7 oxygen atoms is to have a coefficient of 3.5. This is not acceptable.

3.5

Hint: Double all coefficients except the “problem”.

4

4

12

2

4

11

6

12

14Now there are an even # of product

oxygen atoms

7

14

N a m e : _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ D a t e : _ _ _ _ _ _ _ _ _ _ _ _ P e r i o d : _ _ _ _ _ _ _ _ _ _ _

B a l a n c e t h e f o l l o w i n g e q u a t i o n s a n d n a m e e a c h c o m p o u n d !

1 . H 2 + O 2 H 2 O

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

2 . Z n + H C l H 2 + Z n C l 2

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

3 . P b ( N O 3 ) 2 + K 2 S P b S + K N O 3

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

4 . C O 2 + H 2 O H 2 C O 3

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

5 . A l 2 ( S O 4 ) 3 + C a ( O H ) 2 A l ( O H ) 3 + C a S O 4

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

6 . C u + C l 2 C u C l 2

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

7 . M g + H C l M g C l 2 + H 2

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

8 . B a C O 3 + C + H 2 O C O + B a ( O H ) 2

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

9 . R b B r + A g N O 3 A g B r + R b N O 3

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

1 0 . N a 2 C O 3 + C a C l 2 C a C O 3 + N a C l

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

a. Al + O2 Al2O3

b. Al + Fe2O3 Al2O3 + Fe

c. KClO4 KCl + O2

d. Ca(OH)2 + HNO3 Ca(NO3)2 + H2O

e. Cr2(SO4)3 + NaOH Cr(OH)3 + Na2SO4

f. Cu + AgNO3 Cu(NO3)2 + Ag

g. CH4 + O2 CO2 + H2O

h. C2H6 + O2 CO2 + H2O

i. SiO2 + HF SiF4 H2O

j. MgO + H3PO4 Mg3(PO4)2 + H2O

k. PbO2 PbO + O2

l. NaBr + Cl2 Br2 + NaCl

m. Sb2S3 + HCl H3SbCl6 + H2S

n. Ag + HNO3 AgNO3 + NO + H2O (extra credit!)

o. C3H8 + O2 CO2 + H2O

p. FeS2 + O2 Fe2O3 + SO2

Name: __________________

Date: __________ Period:____

Side #1 Side #2

Checking both sides for a grade!Checking both sides for a grade!Checking both sides for a grade!Checking both sides for a grade!Checking both sides for a grade!Checking both sides for a grade!Checking both sides for a grade!Checking both sides for a grade!