Notes, abstracts, papers, exams and problems of Chemistry

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Laws ponderal

Classified in Chemistry

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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

Written at on English with a size of 16.71 KB.

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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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

Classified in Chemistry

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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



Find ut 6 primary 3 rd cycle

Posted by Gorethog and classified in Chemistry

Written at on English with a size of 2.1 KB.

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

Classified in Chemistry

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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" »

Consider an atom that has an atomic number of 8 and a mass number of 17 If it has a -2 charge it contains electrons.

Classified in Chemistry

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ATOMS

the nucleus which is at the middle of the atom- contains protons and neutrons, has positive charge due to protons, almost the whole mass of the atom concentrated here but it´s tiny compared to the rest pf the atom.

The electrons move around the nucleus in enery levels called shells- they are negatively charged, they´re tiny but they cover a lot of space, the size of their orbit determines how big the atom is and they have virtually no mass.
      PROTONS ARE HEAVY AND POSITIVELY CHARGED 
                  NEUTRONS ARE HEAVY AND NEUTRAL
ELECTRONS ARE TINY AND NEGATIVELY CHARGED 

atomic number tells you how many protons there are (bottom number)

Atoms of the same element all have the same number of protons- so atoms of different
... Continue reading "Consider an atom that has an atomic number of 8 and a mass number of 17 If it has a -2 charge it contains electrons." »

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" »

Coh3 chemical name

Classified in Chemistry

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Rutherford and his assistants dealt with the following material: - A radioactive source of α particles (radium). These particles have positive electric charge. - A very thin gold foil (about 10-7 m thick). - A fluorescent detecting screen (zinc sulfide).  nobody expected that 1 or 2 out of 10,000 particles rebounded against the gold foil.

Isotopes are atoms of the same element with different number of neutrons in their nuclei, so they have different mass numbers and different atomic masses.

ión es una partícula cargada eléctricamente constituida por un átomo o molécula que no es eléctricamente neutro.

Matter is made up of atoms.  Atoms cannot be subdivided, destroyed or created.  Atoms of a given element are identical in size, mass... Continue reading "Coh3 chemical name" »