Wednesday, 30 January 2019

Chemical reaction in our daily life

Hii everyone, I am sharing some idea about chemical reaction in our body and its very important know which type of reaction going inside  our body.

In daily Life there's is so many reaction takes place in day to day Life some examples
Some of the observable examples of chemical reactions in everyday life are respiration (aerobic and anaerobic), photosynthesis, rusting and burning.
Look at the things around you, nearly all of them are made up of some sort of substances, which are further classified into element, mixture, alloy, etc. And speaking in chemistry terms, the air we breathe is a mixture in gaseous state, while water is a compound existing in liquid state. Considering the abundance of substances in and around us, it is not unusual to observe examples of chemical reactions in everyday life. Before we discuss the chemical reactions that occur in everyday, let's try to understand what actually takes place a chemical reaction.
What are Chemical Reactions?
A chemical reaction is defined as the process, wherein a set of chemical substances react with each other, which leads to their conversion into other different forms. The initial substances used the reaction are collectively called reactants, while the final substances formed after the reaction are known a products. In general, the chemical properties of the reactants and products are different from each other. Based on whether the reaction is initiated with energy or without energy, it is classified into two types, spontaneous reaction (that occurs on its own) and non-spontaneous reaction (require energy for activation).
Some Chemical Reactions in Everyday Life
Science being a subject of common interest, it is very intriguing to analyze visual experiments happening in day-to-day life. There are a plethora of products that you use everyday, which are formulated with application of chemical reaction. Say for example; toothpaste, soap, shampoo, cleaning agent, etc. are all results of chemical reactions. Following are some of the most profound chemical reactions, which we encounter in everyday life :
Aerobic Respiration
Do you know indulging in physical movements is associated with a chemical reaction? The process requires energy, which is yielded by aerobic respiration. Over here, respiration helps breaks down glucose (an energy source) into water, carbon dioxide and energy in form of ATP (adenosine triphosphate). The balanced cellular respiration equation is represented as:
C6H12O6 + 6O2 → 6CO2+ 6H2O + Energy (36 ATPs)
Anaerobic Respiration
Due to overexercising, sometimes our body cells run out of oxygen and respire anaerobically. This cause synthesis of lactic acid and cause muscle cramps. Anaerobic respiration is observed in some bacteria, yeast and other organisms. In contrary to the aerobic type, it breaks down glucose in the absence of oxygen, resulting in production of ethanol, carbon dioxide and energy. Anaerobic respiration equation is:
C6H12O6→ 2C2H5OH + 2CO2 + Energy
Photosynthesis
Photosynthesis is the process by which green plants manufacture their own food. This occurs in presence of sunlight and other raw materials, namely carbon dioxide and water. The chlorophyll pigment harvests the light energy from sunlight, which is then converted into glucose by the phenomenon of photosynthesis. In short, it is the opposite of aerobic respiration. The equation for photosynthesis is:
6 CO2+ 6 H2O + Light energy → C6H12O6+ 6 O2
Rusting of Iron
Very often, you notice a coating of rust over unpainted iron surfaces, which gradually leads to disintegration of iron. This is nothing, but a chemical phenomenon called rusting. In this case, iron (a very reactive metal) combines with oxygen in presence of water (more precisely, atmospheric moisture), resulting in formation of iron oxides. The chemical reaction behind rusting can be simply represented as:
Fe + O2 + H2O → Fe2O3. XH2O
Propane Grill
Have you ever prepared meat in a propane grill? The meat placed over the burner is cooked with the help of heat energy released after burning of propane gas. Thus, propane is the reactant which when burnt with the help of oxygen gives heat energy and other byproducts. Check out the balanced equation for the combustion reaction that take place in a propane grill:
C3H8 + 5O2→ 4H2O + 3CO2+ energy
Whether you consider cooking, souring, fermenting or burning, there is a chemical reaction accompanying these everyday processes. Thus, it won't be wrong to say learning chemistry and chemical reactions start at home.

Adsorption Isotherm

Hello everyone today I am going to tell you something about adsorption Isotherm.

The process of Adsorption is usually studied through graphs know as adsorption isotherm. It is the graph between the amounts of adsorbate .

What is Adsorption Isotherm?


The process of Adsorption is usually studied through graphs know as adsorption isotherm. It is the graph between the amounts of adsorbate (x) adsorbed on the surface of adsorbent (m) and pressure at constant temperature. Different adsorption isotherms have been Freundlich, Langmuir and BET theory.

Basic Adsorption Isotherm


In the process of adsorption, adsorbate gets adsorbed on adsorbent.
Adsorption
According to Le-Chatelier principle, the direction of equilibrium would shift in that direction where the stress can be relieved. In case of application of excess of pressure to the equilibrium system, the equilibrium will shift in the direction where the number of molecules decreases. Since number of molecules decreases in forward direction, with the increases in pressure, forward direction of equilibrium will be favored.
Basic Adsorption Isotherm
Basic Adsorption Isotherm
From the graph, we can predict that after saturation pressure Ps, adsorption does not occur anymore. This can be explained by the fact that there are limited numbers of vacancies on the surface of the adsorbent. At high pressure a stage is reached when all the sites are occupied and further increase in pressure does not cause any difference in adsorption process. At high pressure, Adsorption is independent of pressure.

Freundlich Adsorption Isotherm


In 1909, Freundlich gave an empirical expression representing the isothermal variation of adsorption of a quantity of gas adsorbed by unit mass of solid adsorbent with pressure. This equation is known as Freundlich Adsorption Isotherm or Freundlich Adsorption equation or simply Freundlich Isotherm.
Freundlich Adsorption equation
Where x is the mass of the gas adsorbed on mass m of the adsorbent at pressure p and k, n are constants whose values depend upon adsorbent and gas at particular temperature. Though Freundlich Isotherm correctly established the relationship of adsorption with pressure at lower values, it failed to predict value of adsorption at higher pressure.

Langmuir Adsorption Isotherm


In 1916 Langmuir proposed another Adsorption Isotherm known as Langmuir Adsorption isotherm. This isotherm was based on different assumptions one of which is that dynamic equilibrium exists between adsorbed gaseous molecules and the free gaseous molecules.
Equation
Where A(g) is unadsorbed gaseous molecule, B(s) is unoccupied metal surface and AB is Adsorbed gaseous molecule.
Based on his theory, he derived Langmuir Equation which depicted a relationship between the number of active sites of the surface undergoing adsorption and pressure.
Langmuir Equation
Where θ the number of sites of the surface which are covered with gaseous molecule, P represents pressure and K is the equilibrium constant for distribution of adsorbate between the surface and the gas phase .The basic limitation of Langmuir adsorption equation is that it is valid at low pressure only.
At lower pressure, KP is so small, that factor (1+KP) in denominator can almost be ignored. So Langmuir equation reduces to
θ = KP
At high pressure KP is so large, that factor (1+KP) in denominator is nearly equal to KP. So Langmuir equation reduces to
Reduced Langmuir equation

BET adsorption Isotherm

BET Theory put forward by Brunauer, Emmett and Teller explained that multilayer formation is the true picture of physical Adsorption.
One of the basic assumptions of Langmuir Adsorption Isotherm was that adsorption is monolayer in nature. Langmuir adsorption equation is applicable under the conditions of low pressure. Under these conditions, gaseous molecules would possess high thermal energy and high escape velocity. As a result of this less number of gaseous molecules would be available near the surface of adsorbent.
Under the condition of high pressure and low temperature, thermal energy of gaseous molecules decreases and more and more gaseous molecules would be available per unit surface area. Due to this multilayer adsorption would occur. The multilayer formation was explained by BET Theory. The BET equation is given as
BET equation
The another form of BET equation is
Another form of BET equation
Where Vmono be the adsorbed volume of gas at high pressure conditions so as to cover the surface with a unilayer of gaseous molecules,
Ratio
the ratio is designated C. K1 is the equilibrium constant when single molecule adsorbed per vacant site and KL is the equilibrium constant to the saturated vapor liquid equilibrium.

Type of Adsorption Isotherm

Five different types of adsorption isotherm and their characteristics are explained below.

Type I Adsorption Isotherm

Type I Adsorption Isotherm
Type I Adsorption Isotherm
  • The above graph depicts Monolayer adsorption.
  • This graph can be easily explained using Langmuir Adsorption Isotherm.
  • If BET equation, when P/P0<<1 and c>>1, then it leads to monolayer formation and Type I Adsorption Isotherm is obtained.
  • Examples of Type-I adsorption are Adsorption of Nitrogen (N2) or Hydrogen (H) on charcoal at temperature near to -1800C.

Type II Adsorption Isotherm

Type II Adsorption Isotherm
Type II Adsorption Isotherm
  • Type II Adsorption Isotherm shows large deviation from Langmuir model of adsorption.
  • The intermediate flat region in the isotherm corresponds to monolayer formation.
  • In BET equation, value of C has to be very large in comparison to 1.
  • Type II
  • Examples of Type-II adsorption are Nitrogen (N2 (g)) adsorbed at -1950C on Iron (Fe) catalyst and Nitrogen (N2 (g)) adsorbed at -1950C on silica gel.

Type III Adsorption Isotherm

Type III Adsorption Isotherm
Type III Adsorption Isotherm
  • Type III Adsorption Isotherm also shows large deviation from Langmuir model.
  • In BET equation value if C <<< 1 Type III Adsorption Isotherm obtained.
  • This isotherm explains the formation of multilayer.
  • There is no flattish portion in the curve which indicates that monolayer formation is missing.
  • Examples of Type III Adsorption Isotherm are Bromine (Br2) at 790C on silica gel or Iodine (I2) at 790C on silica gel.

Type IV Adsorption Isotherm

Type IV Adsorption Isotherm
Type IV Adsorption Isotherm
  • At lower pressure region of graph is quite similar to Type II. This explains formation of monolayer followed by multilayer.
  • The saturation level reaches at a pressure below the saturation vapor pressure .This can be explained on the basis of a possibility of gases getting condensed in the tiny capillary pores of adsorbent at pressure below the saturation pressure (PS) of the gas.
  • Examples of Type IV Adsorption Isotherm are of adsorption of Benzene on Iron Oxide (Fe2O3) at 500C and adsorption of Benzene on silica gel at 500C.

Type V Adsorption Isotherm

Type V Adsorption Isotherm
Type V Adsorption Isotherm
  • Explanation of Type V graph is similar to Type IV.
  • Example of Type V Adsorption Isotherm is adsorption of Water (vapors) at 1000C on charcoal.
  • Type IV and V shows phenomenon of capillary condensation of gas.

Thursday, 24 January 2019

TYPES OF HYBRIDIZATION

Hi everyone today i am going to tell you some idea about hybridization in which i am going tell you types of hybridization.

Following are the types of hybridisation:

1) sp – Hybridisation
In such hybridisation one s- and one p-orbital are mixed to form two sp – hybrid orbitals, having a linear structure with bond angle 180 degrees. For example in the formation of BeCl2
, first be atom comes in excited state 2s1 2p1, then hybridized to form two sp – hybrid orbitals. These hybrid orbitals overlap with the two p-orbitals of two chlorine atoms to form BeCl2
2) sp2 – Hybridisation
In such hybridisation one s- and tow p-orbitals are mixed form three sp2– hybrid orbitals, having a planar triangular structure with bond angle 120 degrees.
3) sp3 – Hybridisation
In such hybridisation one s- and three p-orbitals are mixed to form four sp3– hybrid orbitals having a tetrahedral structure with bond angle 109 degrees 28′, that is, 109.5 degrees. 


Also if  you want some tricks how to find hybridization in very short time follow my youtYou channel CHEM SM and also you visit on following links


https://youtu.be/zIh2UPcCMzI

Thanks everyone's.




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