Balancing Equations

Potassium Iodide and Lead Nitrate are mixed to form a precipitate (solid). After the

reaction the mass of the flask will

1 2 3

33% 33%33%1. Increase2. Decrease3. Stay the same

Chemical Reactions

Shown by chemical equations

4 Cu (s) + 1 O2 (g) 2 Cu2O (s)

coefficients

Symbols

slgaq

yields, reacts to formreversible reactionheat is addedsolidliquidgasaqueous (dissolved in

water)

Sides?

2Fe + O2 2FeO

Reactant(s) Product(s)

“Rust”

Why Balance?

To show that the law of conservation of mass is satisfied

To know the proportions the elements and compounds react in

Balancing Equations usingAtom Inventory

Zn + HBr ZnBr2 + H2

Zn

H

Br

1

1

1

1

2

2

Is everthing balanced?

2

2

2Balanced!!

Leave Polyatomic ions together

AgNO3 + Na2S Ag2S + NaNO3

Ag

S

Na

NO3

1

1

2

1

2

1

1

1

2

2

2

Is everthing balanced?

2

2

2Balanced!!

Never change subscripts

Al2(SO4)3 + HCl H2SO4 + AlCl3

Al

SO4

H

Cl

2

3

1

1

1

1

2

3

Is everthing balanced?

2

6

26

6

6

3

6

3Balanced!!

Websites

www.funbasedlearning.com (open with Internet Explorer)

http://education.jlab.org/elementbalancing/index.html

http://science.widener.edu/svb/tutorial/rxnbalancingcsn7.html