Feiron Pb

lead

AugoldC

carbon

Cocobalt

KpotassiumNe

neon

Nnitrogen

H2O

H is the symbol for Hydrogen

O is the symbol for Oxygen

The subscript means the molecule of water has two atoms of hydrogen

No subscript after oxygen means the molecule of water has only one atom of oxygen.

Chemical Formula

Coefficient

H2O3

Molecule of Water

The coefficient shows the number of molecules of the compound.

C+O2

CO2One atom of carbon

combines with two atoms of oxygen to produce one

molecule of carbon dioxide.

Chemical Equation

Parts of a Chemical Equation

C+O2 CO2

REACTANTS are the starting

materials on the left side of

the arrow.

PRODUCT is the new

substance or substances

produced and are on the right

side of the arrow.

yieldsor

produces

NaOH + HCl

NaCl + H2O

A plus sign separates products when there is more than one new substance produced.

A plus sign (which mean combines or reacts with) separates the reactants.

Law of Conservation of Mass

States that mass (atoms) cannot be created nor

destroyed in a chemical reaction.

There must be the same number of atoms on each side

of the equation.

In a chemical reaction, the total

mass of the materials formed is

the same as the total mass of the

starting materials.

10 atoms of O

P P4O10O2+4 5

4 atoms of P 4 atoms of P

10 atoms of O

=

balanced

H + O2 H2OH =1 atom

O =2 atoms

H =2 atoms

O =1 atom

=

H + O2 H2O2

O =2 atomsO =2 atoms

H =4 atoms

4H =4 atom =

Mg + O2 MgO

Mg = Mg =

O = O =

11

2 1

2

2

2

2

2

Ca + O2 CaO

Ca = Ca =

O = O =

11

2 1

2

2

2

2

2

N2 + H2 NH3

N = N =

H = H =

12

2 3

2

6

2

3

6

Cu2O + C Cu+ CO2

Cu = Cu =

O = O =

C = C =

12

1 2

4

2

4 4

2

1 1

H2O2 H2O + O2

H = H =

O = O =

22

2 3

2

4

4

2

4

4