Chemistry

All about chemistry related fields. Organic chemistry mechanism, chemistry masses, chemistry atoms, chemistry answers etc.

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Chemistry Formulas: Acid formulas.

Nitrous Acid -                  HNO₂
Hypochlorous Acid -        HClO
Chlorous Acid -               HClO₂
Chloric Acid -                 HClO₃
Sulfuric Acid -                 H₂SO₄
Sulfurous Acid -              H₂SO₃
Phosphoric Acid -           H₃PO₄
Phosphorous Acid -        H₃PO₃
Carbonic Acid -             H₂CO₃
Acetic Acid -               HC₂H₃O₂
Oxalic Acid -                H₂C₂O₄
Boric Acid -                 H₃BO₃
Silicic Acid -                H₂SiO₃
Nitric Acid -                HNO₃
Perchloric Acid -         HClO₄

Chemistry Answers: Mcq's of Acid, Basis and Salts:

Which of the following reacts with HCl to give Hydrogen?
A-ammonia
B-iron
C-potassium manganate(VII)
D-silver
E-sodium hydroxide

SOLUTION:
The correct answer is iron (B)

REASON:
Metals which are more active than hydrogen can displace it from acids.

Chemistry atoms: Basic Ideas.

1-All matter is made up of very small, discrete particles called atoms.
2-All atoms of an electron are alike in weight and different from the weight of any other kind of atom.
3-Atoms unite in chemical changes to form compounds.The atom loss its characteristic properties when this combination occurs.
4-The atom is not entirely altered in the formation of a compound, and its weight remains constant.

Chemistry Mass: Molar Mass and Moles:

When the formula weight of an ionic compound is determined by the addition of its component relative atomic masses and expressed in grams, it is called the gram formula weight or Molar Mass. For example CaCO3.


1Ca = 40
1C = 12
3O = 48 = (3*16)
_______________________

 CaCO3 = 100 formula weight
100g = Molar Mass

Organic Chemistry Mechanism: Elbs reaction:

In this method poly nuclear hydrocarbons are produced from a diaryl ketone containing a methyl group in the ortho position to the keto group. The reaction is usually carried out by heating the ketone under reflux at 400-450 0C until water is no longer evolved, e.g: o-methyl benzophenone forms anthracene.

MCQ'S: Acids, Bases and Salts:

The compound SO2Cl2 reacts with water according to the following reaction.


SO2Cl2 + 2H2O  ---------->  H2SO4 + 2HCl

How many moles of  NaOH will neutralise the solution produced by one mole of  SO2Cl2 and excess of water.
A-1
B-2
C-3
D-4
E-5
SOLUTION:

The correct answer is (D)


REASON:

Two moles of NaOH will neutralize one mole of H2SO4 and two moles of NaOH are required for two moles of HCl.

MCQ'S: Acids, Bases and Salts.

One mole of each of the following compound was dissolved in water to make 1dm3 of solution.which of the solution would have lowest PH?

A-ammonia
B-ethanoic acid
C-sodium hydroxide
D-sulphuric acid

SOLUTION:

The answer is E (suphuric acid)

REASON:

The solution with lowest PH must be of a strong acid(H2SO4)


Rooms

MCQS: Which statement about graphite is correct?

A- It conducts electricity because graphite has ions which are free to move.
B- It has an ionic lattice.
C- It has the same structure as diamond.
D- Its structure contains rings of carbon atoms.


SOLUTION:
D- is correct statement due to the reason, In graphite, each layer contains hexagonal ring of carbon atoms with each atom covalently bonded to 3 other atoms.

How to make standard solutions for Chemistry:

There are  two common types of "standard solutions".
1- Molar Solutions
 2-Normal Solutions
 Both of these solutions are concentrations (or “strengths”) of a particular component
(solute) that is dissolved in a solvent.
Making a Molar solution usually involves fewer mental steps than does making a Normal
solutions.

Acids in Laboratories:Hydrocloric acid (HCl)dilute and concentrated

HCl (conc.) 12M (12N)
HCl (dil.)     5M (5N) (Approximately) Dilute 330 mL of conc. acid to 1 litre of water.

Acids in Laboratories:Glacial acetic acid and Acetic acid

Glacial acetic acid 17 M (17N)

Acetic acid(dil.) 5M (5N) Approx. Dilute 220 mL of glacial acetic acid with water to 1 litre.

Geothite:

The second most common mineral of iron after Heamatite, geothite has the formula FeO(OH) and is the principal component of yellow ochre,although it can also be in red color.

Gluon:

Gluon are subatomic particles that bind the fundamental particles 'quarks' together in the nucleus and so are integral to the stronger nuclear force.

Gluons have integer values of the spin quantum number. Quarks interact with one another by emitting and absorbing gluons, just as electrical subatomic particles interact through the emission or absorption of photons.Their existance was proved in 1979 with the observation of gluons by quarks in studies of high energy particle collisions.

An equilibrium constant of Nitric acid:

HNO3(g) + H2O(l) -------> NO3-(aq) + H3O+(aq)

The equilibrium constant expression is
                           K= [NO3-] [H3O+]
                               ---------------------
                                [HNO3] [H2O]

Calomel:

It is known as mercury(I) chloride or mercurous chloride Hg2cl2.calemol is heavy, soft, white mineral which can be fashioned into electrodes for use in electrochemical cells.

Absolute Alcohol:

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The common name given to ethanol ( ethyl alcohol) of low water content is absolute alcohol.Its chemical formula is CH3CH2OH.
Absolute alcohol has no more than 1% impurity; methanol and benzene being common impurities. Ethanol can be produced by fermentation of  Carbohydrates such as wheat or corn, or by the hydration of Ethene, which is the most common large scale industrial production technique.The relevant equation is:
            
                             CH2=CH2(g) + H2O -------> CH3CH2OH(g)

How halogens are detected in an organic compound in the presence of nitrogen and sulphur.

Sodium extract is first boiled with conc.nitric acid before adding silver nitrate solution for detection of halogens. Boiling with nitric acid will destroy the CN and S which if present will give white and black ppt. respectively.

Difference between Organic and Inorganic substances:

Organic compounds are generally covalent in nature whereas the inorganic salts are ionic.On contrary, Organic compounds are restricted to few elements like C, H,O,X, N, S and sometimes metals like Mg, Zn etc.

Chemistry Blog:A Guide Towards Specific Terms Used in Chemistry:

1- Define ( the term )...is intended literally.Only a formal statement or equivalent phrase being required.
2- What do you understand by( What is meant by terms....) normally implies that a definition should be given, together with some relevnt comments on significance of term(s) concerend, especially where two or more terms are included in the question. The amount of supplementary comment intended should be interpreted in the light of the indicated mark value.
3- state implies a concise answer with little or no supporting arguments.
4- Explain may imply reasoning or some reference to theory.
5- Use diagrams where appropriate.
6- Describe requires to state in words the main points of topic.
7- Predict or Deduce implies that the candidate is not expected to produce the answer by recall but by making a logical connection between other pieces of information.
8- Comment is intended as an open ended instruction.
9- Suggest is used to imply that there is no unique answer or expected to apply general knowledge.
10- Find is general term that may be interpreted as calculate, measure, determine etc.
11- Determine means that quantity concerned cannot be measured directly but is obtained by calculation.
12-Estimate implies a reasoned order of magnitude statement or calculation.
13- Sketch, when applied graph work.
14- Construct is often used in relation to chemical equation where a candidate is expected to write balanced chemical equations not by recall but by analogy.

SI Base Units:

1- Mass, Kilogram, Kg
2- Time, Second, s
3- Length, meter, m
4- Electric Current, ampere, A
5- Temperature, Kelvin, K
6- Amount of substance, mole, mol
7-Luminous intensity, candela, cd

Chemistry around the Globe.

Alchemy is a attractive skill with a abundant and famous history. Since time old people have struggled to cause good sense of the creation around them and to harness the powers of nature to their reward.The past Greeks divided up their world into II segments.
The dozen close to chemical element acknowledged to the ancients constituted those that they found approachable them, or that they were capable to acquire on the technology available at the time.Iron, Zinc, Mercury, sulfur and precious metals Silver and Gold have been employed their pure form or as alloys for thousands of year.
In the 20th century the an burst of synthetic material occurred; the present plastics had come into being.Use of semi-conducting metalloids such as Silicon and Germanium has opened the way for the most spectacular revolution in human race handling of its surroundings.