stoichiometry

In chemistry, stoichiometry (sometimes called stoichiometry of reaction to distinguish it from compositional stoichiometry) is a science that uses and quantifies quantitative relationships of reactants and products in chemical reactions. This word comes from the Greek stoikheion (element) and metriā (size).

I. BASIC LAW OF CHEMICAL SCIENCE

A. The Law of Conservation of Mass (Lavoisier Law)

"Mass always and same reaction".

Example:

S + O 2 → SO 2

2 gr 32 gr 64 gr

B. Law of Refine (Proust Law)

"Thank you very much."

Example:

H 2 O → mass H: mass O = 2: 16 = 1: 8

C. Double Law (Dalton's Law)

"If two elements can be formed two or more, and the mass of one element is equal, the mass of the second element is added to a simple and integer".

Example:

- Element N and O can form NO and NO 2 compounds

- In the case of NO, mass N = mass O = 14: 16

- In the case of NO 2, mass N = mass O = 14: 32

- Thank you very much N on NO and NO 2 equals then

Comparison of mass O = 16: 32 = 1: 2

D. Ideal Gas Law

For an ideal gas or a gas that is considered to be valid applies the formula:

PV = n RT

Information:

P = pressure (atmosphere)

V = volume (liters)

N = mol = gram / Tn

R = gas constant (lt.atm / mol.K)

T = temperature (Kelvin)

From the formula can be obtained:

II. MASS OF RELATIVE ATOM AND RELATIVE MOLECULOUS MASS

III. CONCEPT MOL

A. In chemistry the unit of quantity used is mol

B. One mole is the amount of the substance containing 6.02 x 10 ^ 23 particles

The relationship of Moles to the number of particles

Number of Particles = mol x 6.02 x 10 ^ 23

Mol = Number of particles / 6.02 x 10 ^ 23

Relation of Moles to Mass

For element:

• mol = gram / Ar

• gram = mol x Ar

For things:

• mol = gram / Mr

• gram = mole x Mr.

Relation of Mole to Gas Volume

Every one mole of gas of any standard state (0oC, 1 atm) has volume: 22, 4 liters.

• Volume of gas = mol x 22.4

• mol = Volume / 22,4

The mole relationship, the number of particles and the gas relation can be

Diagram as follows