Mass CANNOT be created nor destroyed.

In chemical reaction: the mass of the reactants

equals the mass of the products.

Reactants: starting materials

Products: new materials

Arrow: “goes to form” or “yields”

Coefficients: # in front of formula

Example:

Iron + oxygen iron (III) oxide

4 Fe(s) + 3 O2(g) 2 Fe2O3(s)

1. Count up the number of atoms on the

reactants side and products side.

2. Insert coefficients in front of the chemical

formulae until you have equal numbers of

atoms on each side.

3. Remember:

start with atom that appears in only 1

formula on each side first.

lowest common multiple rule for coefficients

keep polyatomic ions together.

To balance combustion reactions

ie: CxHy + O2 CO2 + H2O

Balance H’s first, then C’s, then O’s last.

If oxygen has an ODD number on product side, add a “fraction /2” coefficient to the oxygen, THEN DOUBLE all compounds and elements on both sides of the equation!!

OR – put the odd coefficient number in front of oxygen on the reactant side and double all other coefficients.

Example: Predict the products:

a) ____CH4 + ____O2 ____CO2 + ____ H2O

b) ____ C2H6 + ____O2 ____CO2 + ____ H2O

c) ____ C5H12 + ____O2 ____CO2 + ____ H2O

A. Formation (Synthesis)

element + element compound

B. Simple Decomposition

compound element + element

C. Single Replacement

element + compound element + compound

D. Double Replacement

compound + compound compound + compound

E. Neutralization (Acid/Base)

acid + base salt + water

F. Combustion

CXHY + O2 CO2 + H2O

Element + Element Compound

Examples: 2Co(s) + 3F2(g) 2CoF3(s)

2Mg(s) + Cl2(g) Mg2Cl(s)

Compound Element + Element

Examples: Si2 (s) 2Si(s) + 2Br2(l)

2H2O(l) 2H2(g)+O2(g)

Element + Compound Element + Compound

Examples: Zn(s) + CuSO4(aq) Cu(s) + ZnSO4(aq)

Cl2(g) + 2NaBr(aq) 2NaCl(aq) + Br2(l)

NEW! NEW!

Compound + Compound Compound + Compound

Example: AgNO3(aq) + NaCl(aq) AgCl(s) + NaNO3(aq)

NEW! NEW!

When a acid and base mix together they

neutralize each other.

acid + base salt + water

Example: H3PO4 + 3NaOH Na3PO4 + 3H2O

Common uses:

1. Lemon juice to neutralize fish odor

2. Antacids - TUMS

3. pH test in swimming pool

4. Baking soda in refrigerator

Acids

1. taste sour

2. turn blue litmus red

3. react with metals

4. conduct electricity

5. neutralize bases

6. pH is less than 7

7. Most soluble in water

Bases

1. taste bitter2. turns red litmus blue3. feel slippery4. conduct electricity5. neutralize acids6. pH is more than 77. does not react with metals8. Variable solubility in water

CxHy + O2 CO2 + H2O

Example: C3H8(g) + 5O2(g) CO2(g) + 4H2O(g)

Combustion equations

What are some chemical processes that

surround our everyday lives?

Pharmaceuticals

Photography

Biochemistry

Medicine

Pharmacology

Environmental

science

What are some

chemistry-related careers?

Case Study: P. 278

Read as a class – discuss Question a-e, # 2,3,4

Chemistry Laboratory Activities

Testing properties of Substances

Additional activity add – color change and precipitate