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Basic Laws of Chemistry
Stoichiometry is the branch of chemistry that studies the quantitative relationship of the composition of chemical substances and reactions.
1.LAW OF CONSERVATION OF MASS = Lavoisier LAW
"The mass of substances before and after the reaction is fixed".

Example:
hydrogen + oxygen ® hydrogen oxide
   (4g) (32g) (36g)

2.COMPARATIVE LAW = LEGAL PERMANENT Proust
"Comparison of the mass of the elements in each compound is fixed"

Example:
a. In the compound NH3: N mass: mass of H
Ar = 1. N: 3 Ar. H
= 1 (14): 3 (1) = 14: 3
b. On the compound SO3: S mass: mass 0
Ar = 1. S: 3 Ar. O
= 1 (32): 3 (16) = 32: 48 = 2: 3

Advantages of the law Proust:
if known mass of a compound or a mass of one of the elements that make up the compound make-masses of other elements can be determined.

Example:
How many levels of C in 50 grams of CaCO3? (Ar: C = 12; 0 = 16; Ca = 40)
Mass C = (Ar C / Mr CaCO3) x mass of CaCO3
= 12/100 x 50 grams = 6 grams
mass C
Levels of C = mass C / mass x 100% CaCO3
= 6/50 x 100% = 12%

3.COMPARATIVE LAW LAW MULTIPLE = DALTON
"When the two elements can form two or more compounds to the mass of one element as much the second element of the mass ratio in value as integers and simple".

Example:

If the element nitrogen fertilized den oxygen can be formed,
NO where mass N: 0 = 14: 16 = 7: 8
NO2 which the mass N: 0 = 14: 32 = 7: 16

For the same amount of nitrogen mass ratio of the mass of oxygen in the compound NO: NO2 = 8: 16 = 1: 2

4.GAS LAWS
To apply the ideal gas equation: PV = nRT

where:
P = gas pressure (atmospheric)
V = gas volume (liters)
n = moles of gas
R = universal gas constant = 0082 lt.atm / mol Kelvin
T = absolute temperature (Kelvin)

The changes of P, V and T from state 1 to state 2 with certain conditions reflected by the following laws:

A.BOYLE LAW
This law is derived from the ideal gas equation of state with
n1 = n2 and T1 = T2; thus obtained: P1 V1 = P2 V2

Example:
What is the pressure of 0 5 mol O2 with a volume of 10 liters when the temperature is 0.5 mol NH3 has a volume of 5 liters den 2 atmospheric pressure?

Answer:
P1 V1 = P2 V2
2.5 = P2. 10 ® P2 = 1 atmosphere

B.LEGAL Gay-Lussac
"The volume of gases that react den gas volume bile reaction products were measured at the same temperature and pressure, will be compared as integers modest den".

So for: P1 = P2 and T1 = T2 holds: V1 / V2 = n1 / n2

Example:
Calculate the mass of 10 liters of nitrogen gas (N2) if the condition is 1 liter of hydrogen gas (H2) mass of 0.1 g.
Given: Ar for H = 1 and N = 14

Answer:

V1/V2 = n1/n2 ® 10/1 = (x/28) / (0.1 / 2) ® x = 14 grams

So mass = 14 grams of nitrogen gas.

C.BOYLE LAW-Gay Lussac
This law is an extension of the previous law is spoken with the state price den n = n2 to obtain the equation:

P1. V1 / T1 = P2. V2 / T2

D. Avogadro's law
"At the same temperature and pressure, gases equal volume containing the same number of moles. From this statement it is determined that the state of STP (0o C 1 atm) 1 mole of any gas volume of 22.4 liters of volume is referred to as the molar volume of gas.

Example:
What volume of 8.5 grams of ammonia (NH3) at a temperature of 27o C and a pressure of 1 atm?
(Ar: H = 1, N = 14)

Answer:
85 g of ammonia = 17 mol = 0.5 mol

The volume of ammonia (STP) = 0.5 x 4.22 = 2.11 liters

According to Boyle-Gay Lussac equation:

P1. V1 / T1 = P2. V2 / T2
1 x 112.1 / 273 = 1 x V2 / (273 + 27) ® V2 = 12:31 liters