Notes, abstracts, papers, exams and problems of Chemistry

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Laws ponderal

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pure substance: is a phase of uniform composition and unchanging can not be decomposed into other substances of different classes by physical methods.

elements: they are pure substances that can not be decomposed into simpler ones through normal chemical processes.

compounds: they are pure substances made up of two or more elements, which can be decomposed by chemical methods on the elements of which are constituted. A compound always has the same elements and the same proportions regardless of the process followed.



Blended is an aggregation of different substances without causing any chemical reaction between them and therefore may be separated by physical methods.

ponderal laws: they refer to the quantity of matter of different substances... Continue reading "Laws ponderal" »

Farmaco

Classified in Chemistry

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Digestive system drugs
Mucosal protective:
· Sulcralfato: not absorbed form film on the surface of the stomach, protects against erosion of the wall, prevents ulcers, and promotes healing.
· Carbenoxolone: active principle of liquorice. It stimulates the secretion of stomach wall mucus, the mucus is thicker and adheres well to the wall protecting it. It is absorbed in the digestive tract fluid retention and edema. It is contraindicated in hypertensive patients.
Secretion inhibitors:
· H2 antihistamines: HCL inhibits secretion. Used cimetidine. Ranitidine and famotidine, are indicated in gastric or duodenal ulcer, oesophagitis. They can give diarrhea or constipation, dizziness.
· Inhibitors hydrogen bomb: Omeprazole. H inhibits the... Continue reading "Farmaco" »

Coh3 chemical name

Classified in Chemistry

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CHEMISTRY 

 Atom 
An atom is the smallest  stable unit of matter 

Element 
An element is a pure substance made of only one type of atom.
There are about 120 elements , so 120 different atoms exist.

In the periodic table the elements are organized in rows.
The vertical columns are called groups
The horizontal rows are called periods. 
Li, Na and k are in the same group 
N , O , F are in the same period. 
If the elements are in the same group they have the same number of electrons in the outer shell.
This elements in their same groups can have similar chemical and physical  properties. 

Some groups have specific names :

Group 1 elements : are named ALKALI 
Group 2 elements : ALKALI EARTH METALS
Group 7 elements : HALOGEN 
Group 0 elements : NOBLE
... Continue reading "Coh3 chemical name" »

Coh3 chemical name

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mixture is made up of more than one component.

Element is made up of one type of atom (element).
Colloids are mixtures in which the particles of the solute cannot be seen by the naked eye but can be using a microscope. 
heterogeneous system is a mixture of substances whose components are not distributed uniformly and can be distinguished by the naked eye.
Compoundis a composed of two or more different atoms chemically bonded to one another. 
homogeneous system has a uniform distribution and the same physical and chemical properties at all points
A pure substance is made up of a single component with constant physical and chemical properties.

chem final

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Chem Cheat Sheet

Mol = M*L

m = mol/Kg

Strong Acids

HCL hydrochloric

H2SO4 sulfuric

HNO3 nitric

HBR hydrobromic

HI hydroiodic

HCLO4 perchloric

Cp H2O (l) = 4.184

Cp H2O (s) = 2.03

Cp H2O (g) = 1.998

ΔHfusion of H20 = 6.02

ΔHvap of H20 = 40.7



Boiling/melt pt

volatility

Solubility in water

conductivity

examples

Network Cov

Very high

Very low

insoluble

non-conduct

diamond

Ionic

Very high

Very low

Very soluble

Conducts if L or G

salt

metallic

Mostly high

Very low

insoluble

Good conduc

gold

H-bonding

Relativly high

Relativly low

Very soluble

Non conduct

water

Dipole dipole

moderate

moderate

Mostly sol

Non conduct


LDF

Very low

Very high

insoluble

Non conduct



Coh3 chemical name

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Ductility: Able to undergo change of form without breaking

·Malleability: capable of being shaped, as by Hammering or pressing:

·Density (give an Example): a measurement of how Tightly matter is crammed together. Example: Oil floats on vinegar because Its density is less.


  • Chemical properties of matter (give an Example): Are any of the properties Of matter that may only be observed and measured by performing a chemical change or chemical Reaction. Example: oxidation states

·What is a physical Change (give an example): A usually reversible change in the physical 

properties of a substance,as size or shape. Example: When melting an ice cube.

·Difference between Chemical properties and physical properties (give an example)

... Continue reading "Coh3 chemical name" »

Find ut 6 primary 3 rd cycle

Posted by Gorethog and classified in Chemistry

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N = the number of particles

NA = 6.02*10^23 particles/mol

n = moles

N = n * NA

mass / molar mass = mol

n = N /NA

percent composion of s = mass of s / mass of compund *100

Identifying limiting reactant :

1) masses to moles

2)use mole ration

3) limiting reactant is the one that is with the smallest num

Percent yield:

1)Divide given yeild by the limiting reactant

2) multiply by 100

Finding the Formula of a Hydrate:

 1. Find the # of g of MN and # of g of H 2 O.

 2. Convert g to mol.

3. Divide each “# of mol” by the smallest “# of mol.”

4. Use the ratio to find the hydrate’s formula.

Mass percent of water in Ba(OH)2 . XH2O

= (Total mass of sample) - (Mass of Ba(OH)2 in sample) / (Total mass of sample)  * 100

Ba(OH)2

molar mass molecular mass /molar

... Continue reading "Find ut 6 primary 3 rd cycle" »

11 experiment

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Procedure - 
1) Observe the slides showing binary fission in amoeba under a compund microscoope.
2) first,adjust the slides under low power objective lens.If needed shift to high power objective lens.
3) Note down the observations.
Observation -
binary fission in amoeba.
1) binary fission starts with the division of nucleus.
2) The cytoplasm shows the formation of a transverse furrow after the division of nucleus.
3) This furrow deepens and divides the amoeba into tow daughter amoeba.
Inference - Both binary fission are sexual modes of reproduction.


Cuso4 : Aluminium 
Blue colur of CuSo4 disappears.The brown coloured copper at the bottom of the beaker.
copper is displaced.
Cuso4 : zinc
blue colour of copper sulphate disappears and red -brown copper particles
... Continue reading "11 experiment" »

Behaviouralism disregards political culture

Classified in Chemistry

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intro: thompson was a historian with marxist background whose interest in radical political works sets him appart from others authors we studied. He, as hoggart, followed culturalism, a perspective that stresses human agency, or the active pruduction of culture and not its passive consumption. His book The making of the english working class really embodies the term, since in it he traces the development on the english working class between 1780 and 1832, more or less the time encompassed by the industrial revolution. The book can be seen as a rescue operation of the members (especially radicals) of the working class lost in a history lead by the deaths of monarchs, statesman, military leadersand politicians. These "other historiess" with the
... Continue reading "Behaviouralism disregards political culture" »

Polarized covalent bond

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- Hydrogen bonding will be much stronger with H2O because H2O forms a ring like structure due to high ability of hydrogen bonding. In the other hand, ammonia's hydrogen bonding is limited due to having 3 hydrogen atoms. Nitrogen has only one lone pair that cant satisfy all 3 hydrogens. Therefore, H20 has a stronger bonded structure.

- a) magnesium, b) chlorine, c) Vanadium, d) Rubidium

- Ionization energy is the energy required to remove an electron from a neutral atom in its gaseous phase. Conceptually, ionization energy is the opposite of electronegativity. The lower this energy is, the more readily the atom becomes a cation. Therefore, the higher this energy is, the more unlikely it is the atom becomes a cation. When moving to the right

... Continue reading "Polarized covalent bond" »