Tuesday, December 25, 2012

List of Chemical Compounds

A pure chemical substance consisting of two or more different chemical elements which can be separated into simpler substances by chemical reactions is called chemical compound. They exhibit a unique and defined chemical structure. Chemical compounds may be molecular compounds which are held together by covalent bonds, salts by ionic bonds, intermetallic compounds by metallic bonds, or complexes by coordinate covalent bonds. Pure chemical elements are not referred as chemical compounds if they contain molecules which have multiple atoms of a single element like H2, S8.


Introduction:

Elements turn into compounds and become more stable. When compounds have the maximum number of possible electrons in their outermost energy level, which is normally two or eight valence electrons, they become stable. For this reason only noble gases do not react very fast as they have eight valence electrons.

List of Compounds

Compounds are classified into the following three lists:

1) List of inorganic compounds: These compounds are without a C-H bond

2) List of organic compounds: These compounds are with a C-H bond

3) List of biomolecules.

List for Chemical Compounds

Acetic acid

Acetylcholine

Agar

Amylase

Ascorbic acid (vitamin C)

Asparagines

Aspartic acid

Auxin

Bilirubin 

Biotin (Vitamin H)

Caffeine

Calciferol (Vitamin D)

calcitonin

Cannabinol

Casein

Cellulose

Chlorophyll

Cholecystokinin (CCK)

Cholesterol

Choline

Citric acid

Citrulline

Cobalamin (vitamin B12)

Coenzyme

Colchicine

Collagen

Cysteine

Cystine

Cytidine

Cytochalasin

Deoxyribose

Deoxyribose nucleic acid (DNA)

Dopamine

Enzyme

Ephedrine

Epinephrine – C9H13NO3

Fatty acid

Fibrin

Folic acid (Vitamin M)

Follicle stimulating hormone (FSH)

Formaldehyde

Formic acid

Fructose

Galactose

Gastrin

Gelatin

Globulin

Glucagon 

Glucose – C6H12O6

Glucose oxidase

Glycine

Glycogen

Glycolic acid

Glycoprotein

Gonadotropin-releasing hormone (GnRH)

Growth hormone

GTPase

Guanine

Guanosine

Guanosine triphosphate (+GTP)

Hemocyanin

Hemoglobin

Histamine

Histidine

Histone

Histone methyltransferase

Hormone

Human growth hormone

Inositol

Insulin

Integral membrane protein

Integrase

Interferon

Isoleucine

Keratin

Kinase

Lactase

Lactic acid

Lactose

Leucine

Linoleic acid

Linolenic acid

Lipase

Lipid

Luteinizing hormone (LH)

Lysine

Lysozyme

Malic acid

Maltose

Melatonin

Membrane protein

Metalloprotein

Myoglobin

Myosin

Nucleic Acid

Oestrogens

Ornithine

Oxalic acid

Oxidase

Paclitaxel

Palmitic acid

Pantothenic acid (vitamin B5)

parathyroid hormone (PTH)

Penicillin

Pepsin

Peripheral membrane protein

phosphatase

Phospholipid

Phenylalanine

Polysaccharide

Porphyrin

Progesterone

Prolactin (PRL)

Proline

Propionic acid

Protamine

Protease

Protein

Proteinoid

Pyruvic acid

Quinone

Raffinose

RNA - Ribonucleic acid

RuBisCO

Sucrose (sugar)

Sugars (in general)

Tartaric acid 

Topoisomerase

Tyrosine

Uracil

Urea

Urease

Uric acid – C5H4N4O3

Uridine

Valine

Vasopressin

Vitamins (in general)

Water

Xylose
Check my best blog Oxidaton.

Oxidaton

Oxidation is a process in which Oxygen is added to a element or when hydrogen is removed from the molecule or electrons are removed from the atom.

Introduction:

For example:

2H2(g)  + O2(g)  ------> 2H2O(g)
2Mg(s)  + O2(g)  -----> 2MgO(s)

Here hydrogen is oxidized because oxygen is added to Hydrogen. Magnesium is also oxidized by oxygen.
2H2S(g)   + O2(g)    ----> 2S(s)  + 2H2O(l)

In the above reaction H2S is oxidized since Hydrogen is removed from H2S
Zn (s)--------> Zn2+ (aq) + 2e-

In the above example the Zinc is oxidized into Zn2+. Zinc looses two electron to form the ion. Since it looses electron it is oxidation. Oxidation is a part of redox reaction. In this type of reaction reduction and oxidation takes place simultaneously.

Addition of other electronegative elements are also considered as oxidation.For example
Mg(s) +  F2(g)  -----> MgF2(s)
2K(s)  + Cl2(g)  ----> 2KCl(s)

In the above example Magnesium is oxidized to Mg2+ by flourine and  potassium is oxidized to K+ by the chlorine. 

Examples of Oxidaton Reaction

Combustion of methane is an example of oxidation reaction.  For example methane is oxidized to carbon dioxide and water when ignited
CH4  +2 O2  ----->  CO2  + 2H2O
Iron article is oxidized to Fe3O4 when exposed to air and water. Oxidation is unwanted in the case of iron and to prevent it normally painting is done on the Iron.  Galvanization of Iron is another method to prevent the oxidation of Iron which is called as corrosion.   Chrome plating of Iron is another method in which Iron is coated with Chromium so that the iron is not oxidized.
Oxidation process finds many application.  Redox reaction which involves oxidation and reduction is used for volumetric determination of unknown amount of substance from the known amount of the compound.

Wednesday, December 19, 2012

Molecular Orbital Energy

Introduction

A molecular orbital energy level diagram is a qualitative descriptive tool explaining chemical bonding in molecules in terms of molecular orbital theory in general and the Linear combination of atomic orbitals molecular orbital method in particular.

Molecular Orbital Energy

Molecular orbital energy depends upon the two factors:

(i) The energies of the atomic orbitals gets combine to form molecular orbitals.

(ii) The overlapping between the atomic orbitals.

Greater the overlapping, more the bonding orbital is lowered and the antibonding orbital is raised in energy relative to atomic orbitals. For e.g; the extent of overlapping in case of s - orbital is greater than that in p - orbital. Consequently, the energy of a s2pz is lesser than the energy of bonding p2px or p2py MOs.

Now, 1s atomic orbitals of two atoms form two molecular orbitals named as s1s and s*1s. The 2s and 2p orbitals form four bonding molecular orbitals and four antibonding molecular orbitals as:

Bonding molecular orbitals:


s2s, s2pz , p2px , p2py

Antibonding molecular orbitals:


s*2s, s *2pz, p*2px, p*2py

The energy levels of these molecular orbitals have been examined experimentally by spectroscopic methods. The order of increasing molecular orbital’s energy is obtained by the combination of 1s, 2s and 2p orbitals of two atoms is:

s1s, s*1s, s2s, s*2s, s2pz, p2Px = p2py, p*2px = p*2py, s*2pz

Here the energy of molecular orbitals increases from s1s to s*2pz.

However, experimental proofs for some diatomic molecules have shown that above sequence of energy levels of MOs is not correct for all molecules. For e.g., for homonuclear diatomic molecules of second row elements in periodic table such as B2, C2, N2, the s*2pz molecular orbital is higher in energy than p2px andp 2py MOs. The order of MOs for such type of molecules is:

s1s, s *1s, s 2s, s 2s, p2Px = p 2py, s *2pz, p *2px = p *2py,

 s *2pz.

Here the energy of molecular orbitals increases from s1s to s*2pz.

But for molecules O2 onwards (O2, F2), the first order of energies of molecular orbital is correct. Thus, for diatomic molecules of second period, there are two types of energy level diagram of Mos.

Conclusion for Molecular Orbital Energy

The main difference between the two types of sequences is that for molecules O2, F2 and Ne2 the s2pz, molecular orbital has lower energy than p2px and p2py MOs while in the case of molecules Li2, Be2, B2, C2 and N2, s2pz, molecular orbital is higher in energy than p2px and p2py MOs.

Tuesday, December 18, 2012

Electrochemical Impulses

Introduction:


Electrochemical impulses also called nerve impulses or action potential are conducted by specialized cells called neurons. All neurons conduct impulses along hair like cytoplasmic extensions, the nerve fibers or axons outside the central nervous system. A short-lasting event, in which the electrical membrane potential of a cell rises rapidly and falls, is known as an action potential.
In several types of animal cells, action potential occurs. These cells are called excitable cells which include neurons, muscle cells, and endocrine cells.

Function of Electrochemical Impulses:

In neurons, cell-to-cell communication is the major role of action potential. In other types of cells, activation of intracellular processes is their major function.

Mechanism of Electrochemical Impulses:

An action potential is the first step in the chain of events leading to contraction in muscle cells. They provoke release of insulin in beta cells of the pancreas. Special types of voltage gated ion-channels embedded in a cell's plasma membrane are responsible for generation of Action potential. When the membrane potential is near the resting potential of the cell, these channels are shut but they rapidly begin to open if the membrane potential increases to a precisely defined threshold value.

When the channels open, an inward flow of sodium ions is allowed, which changes the electrochemical gradient, which in turn produces a further rise in the membrane potential. This causes more channels to open, producing a greater electrical current. Until the entire ion channels are open, the process proceeds explosively leading to a large upswing in the membrane potential. The polarity of the plasma membrane gets reversed and the ion channels then rapidly inactivate because of the rapid influx of sodium ions.

As the sodium channels closes, it does not allow entry of sodium ions and they are actively transported out the plasma membrane. There is an outward current of potassium ions as potassium channels channels are activated, which returns the electrochemical gradient to the resting state.

Tuesday, December 11, 2012

Potassium Chloride Crystals

Introduction :
Potassium chloride crystals are the inorganic chemical compound, which is represented by the molecular formula KCl and the molar mass is 74.55g. Potassium chloride crystals is the salt of metal halide. Potassium chloride crystals are odorless and it is white in color and it is a crystalline solid.  The boiling and melting point of potassium chloride crystals are 1420°C and 770°C respectively. Potassium chloride crystals are soluble in water. Potassium chloride crystals have face centered cubic structure. Rarely potassium chloride crystals are known as muriate of potash.   It is toxic in excess if we intake orally.  It is hygroscopic in nature.  Potassium chloride crystal was discovered by Sir Humphrey Davy in 1807.

The appearance potassium chloride crystals is shown below,

              

Preparation and Structure of Potassium Chloride Crystals:

Preparation of Potassium chloride:
Potassium chloride crystals naturally occurs as sylvite, so potassium chloride is easily extracted from sylvinite.  It is obtained as a by-product in the preparation of nitric acid from hydrochloric acid and potassium nitrate. i.e.
KNO3 + HCl ===> HNO3 + KCl

Chemical properties of Potassium chloride crystals:

Potassium chloride crystals can react with silver nitrate to give silver chloride.
KCl + AgNO3 ==> AgCl + KNo3
Since potassium is more electropositive than sodium, so it is reduced to potassium metal
KCl (l) + Na (l) ⇌ NaCl (l) + K (g).

Structure of Potassium chloride crystal:
The structure o potassium chloride is face centered cubic.  The lattice constants are equal at 630 picometers .The potassium and the chloride ions are bonded through ionic bond.


Applications of Potassium Chloride Crystals:

Potassium chloride crystals have many applications; few of them are as below,
  • Solution of potassium chloride crystals are used as strong electrolytes.
  • They are used as good conductors of heat and electricity.
  • In infrared and FTIR spectrophotometers, potassium chloride is commonly used as infrared transmission crystal windows in liquid and gaseous sample.
  • It is used in preparation of fertilizers.
  • It is also used in the manufacture of potassium metal and potassium hydroxide and also used as medicine.
  • It is used as fire extinguishing agent.
  • Like sodium chloride, it is used as flux for the gas welding of aluminium

Tuesday, December 4, 2012

Boyle’s law

Ideal gases are composed of rigid sphere molecules which are in random motion.  They can colloid with other molecules and wall of container. The collisions between molecules are completely elastic and due to this there is no loss of energy during collision. The average kinetic energy of molecules is directly proportional to temperature. All properties of ideal gas can be described by ideal gas equation given by;
PV = nRT

I like to share this Potential and Kinetic Energy with you all through my blog.

Ideal gas law is a combination of ideal gas laws which give relation between variables of gases like pressure, number of moles of gas, temperature and volume. Let’s discuss one of the laws known as Boyle’s law.

In 1626, Robert Boyle purposed a relationship between the pressure (p) and the volume (V) of a confined gas held at a constant temperature and for a constant amount.

Let’s first define Boyle’s law. According to Boyle’s law, the product of the pressure and volume is nearly constant at constant temperature and number of moles of an ideal gas. See what is Boyle’s

Law Formula from the given definition, it would be;
P x V = constant (at constant T and n)
Or P  ? 1/V

Boyle’s law can be written for two different volume and pressure;
P1V1= k = P2V2
Or P1V1= P2V2

Boyle’s law graph can be shown in two ways; P v/s V (hyperbola) and P v/s 1/V (linear). The
graphical representation of Boyle’s law is follow;




This law can only apply on an ideal gas not on real gases. The pressure and volume do not show same relationship on the compression of real gas. However this law is good enough to calculate the pressure and volume of internal-combustion engines and steam engines.

Boyle’s Law can explain by using Boyle’s law demonstration.  Let’s take a gas cylinder and put a piston on that for applying pressure on gas.  Keep this cylinder in water bath to maintain constant temperature throughout the experiment.  At initial stage; pressure of gas is 1 atm and volume is 8 ml. As we doubled the pressure that is 1 x 2 atm=2 atm, volume of gas becomes half; 8/2=4 ml.  Again the same thing observed as we double pressure, volume of gas becomes half.





It proves that at constant temperature and constant amount of gas, the pressure of gas is inversely proportional to the volume of gas.  This is because, as pressure on gas increases, the intermolecular space between molecules decreases and they come closer to each other.

For example; in a balloon as the pressure around a balloon are increases, volume of balloon decrease and vice-versa.

Check my best blog Balance equations.

Balance equations

A chemical reaction can represent by using a balance chemical equation.  A balance chemical equation shows reactant and product involve in given reaction with their chemical formulas. A chemical equation also represents, the phases of the participants (solid, liquid, gas) as well as the amount of each substance involve in reaction.

How to Balance a Chemical Equation: Chemical Equation Balancing is a step wise process. Let’s learn how to balance a chemical equation step by step.

1) First write the unbalanced equation by using chemical formulas of reactants and product.

2) Remember, of reactants are listed on the left hand side of the equation and Products on the right hand side.

3) One arrow is used to separated reactant and product to show the direction of reaction.

4) Balancing a chemical equation is based on the Law of Conservation of Mass which states that there are same numbers of atoms of every element on each side of the equation.

5) Balance all elements one by one on both sides by placing coefficients in front of them.

6) Indicate the phase of the reactants and products by using symbols like for use (g) for gaseous state, (s) for solids, (l) for liquids and (aq) for aqueous solution.

Balancing Chemical Equation Problems: For balancing a chemical equation practice, let’s do some problems;

Balance the given chemical equation; __KOH + __ H3PO4  __ K3PO4 + __ H2O

Let’s start from first element ‘K’. Since there is one carbon on left side but three on right side, therefore for balancing ‘K’ put coefficient three on left side before KOH.


3KOH + __ H3PO4  __ K3PO4 + __ H2O


Looking at the next atom (oxygen), the right hand side has seven atoms (three in KOH and four in H3PO4 , while the left hand side has five. To balance the oxygen, coefficient three goes in front of the H2O;


3KOH + __ H3PO4  __ K3PO4 + 3H2O


Now inspect next atom that is hydrogen, on right side there are six atoms and same number is on left side, therefore hydrogen atom is balanced on both side.
Inspection of the last atom to be balanced (phosphorus) shows that the right hand side has atom, similarly on the left hand side has one. Hence the balanced chemical equation can be written as

3KOH + H3PO4  K3PO4 + 3H2O


Balancing Chemical Equation Practice

Some other examples of balanced chemical equation are as follow;

  1. 2 Fe + 3H2SO4 Fe2(SO4)3 + 3H2
  2. 2 C2H6 + 7O2 6 H2O + 4CO2
  3. 4 NH3 + 5 O2 4 NO + 6 H2O
  4. 1 B2Br6 + 6 HNO3  2 B(NO3)3 + 6 HBr
Check my best blog Nitrogen Family of Elements.