Rabu, 07 November 2012

CHEMICAL

Mol Concepts

a) Definition of Mol
o A mole is the amount of a substance that contains the number of particles = number of atoms contained in 12 grams of C-12.
o mole is a unit number (eg dozen, gross), but its size is much larger.
o Mol linking mass by the number of particles of matter.
o The number of particles in one mole (in 12 grams of C-12) are determined through a variety of experimental methods and now we receive is 6.02 x 10 23 (called the Avogadro constant, denoted by L).
Example:
1 mole of water that is to say: so grams of water containing 6.02 x 10 23 molecules of water.
1 mole of iron means: iron-containing gram so 6.02 x 10 23 atoms of iron.
1 mole of sulfuric acid means: so grams of sulfuric acid containing 6.02 x 10 23 molecules of H 2 SO 4.
1 mole = 6.02 x 10 23 particles
L = 6.02 x 10 23
b) Relationship with the Number of Particles Mol
Description:
n = number of moles
 = Number of particles
c) Molar Mass (m m)
o Mass Molar mass of one mole of a substance expressed.
o units are g mol -1.
o Molar mass of substances associated with Ar or Mr substance that, because of Ar or Mr substance is the ratio between the mass of the particles of matter with atom C-12.
Example:
Zar Fe = 56, mean: 1 atom Fe mass: the mass of 1 atom C-12 = 56: 12
Mr H 2 O = 18, mean: mass of 1 molecule of water: the mass of 1 atom C-12 = 18: 12


Because:
1 mole of C-12 = 12 grams (standard mol), then:
Conclusion:
The mass of one mole of a substance = Ar or Mr substance (expressed in grams).
For elements in the form of atomic particles: mm = Ar g mol -1
For other substances: m m = Mr g mol -1
d) Relationship Amount Mol (n) with Substance Mass (m)
Formulated:

with:
m = mass
n = number of moles
m m = mass molar
e) Gas Molar Volume (V m)
o Is the volume of 1 mol of gas.
o According to Avogadro, at the same temperature and pressure, gases bervolum together will contain the number of molecules of the same.
o That is, at the same temperature and pressure, gases with the same number of molecules will have the same volume as well.
o Because 1 mole of any gas has the same number of molecules is 6.02 x 10 23 molecules, then at the same temperature and pressure, one mole of any gas has the same volume.
o So: at the same temperature and pressure, the volume of gas depends only on the number of molnya.
Formulated:


with:
V = volume of gas
n = number of moles
Vm = molar volume
Some of the conditions / circumstances commonly used as a reference:
1) State Standards
Is a state with a temperature of 0 ° C and a pressure of 1 atm.
Expressed in terms of STP (Standard Temperature and Pressure).
In the state of STP, gas molar volume (V m) = 22.4 liters / mol
2) Situation Room
Is a state with a temperature of 25 o C and a pressure of 1 atm.
Expressed in terms of RTP (Room Temperature and Pressure).
In the state of RTP, gas molar volume (V m) = 24 liters / mol
3) Certain state with temperature and pressure are known
Used formula Ideal Gas Equation:
P = gas pressure (atm), 1 atm = 76 cmHg = 760 mmHg
V = volume of gas (L)
n = number of moles of gas
R = the gas constant (0.082 L atm / mol K)
T = the absolute temperature of the gas (in Kelvin = 273 + Celsius temperatures)
4) Referring to the situation Circumstances Other Gas
For example:
By the number of moles of gas A = n = 1 and volume V 1
Gas B with the number of moles = n = 2 and volume V 2
So at the same temperature and pressure:

f) Kemolaran Solution (M)
Kemolaran is a way to express the concentration (density) solution.
Stating the number of moles of solute in each liter of solution, or the number of mmol of solute in each mL of solution.
Formulated:
with:
M = kemolaran solution
n = number of moles of solute
V = volume of solution
For example: 0.2 M NaCl solution means that, in each liter of solution contained 0.2 mol (= 11.7 grams) of NaCl or in each mL of solution contained 0.2 mmol (= 11.7 mg) NaCl.




Tidak ada komentar:

Posting Komentar