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Tuesday, February 24, 2015

Isomerism of coordination compounds - Structural Isomerism

       1.     Structural Isomerism:
         a)    Ionization Isomerism: It occurs when the ligands in the complex can be exchanged with the anions present outside the coordination sphere.

          b)    Hydrated isomerism: it occurs when different number of water molecules are present inside and outside the coordination sphere.

         c)     Linkage Isomerism: Occurs in ambidentate ligands.

         d)    Coordination Isomerism: It occurs when both cations and anions are complexes in such cases the ligand or the central metal atom or both can be exchanged.

Monday, February 23, 2015

What to focus to get a better score and rank...??

From the previous post on electricity,  you came to know the important concepts on capacitors and electrostatics. Now, it’s time to know more about the remaining concepts left behind. Electromagnetism forms a very huge portion of IIT-JEE physics. If practiced carefully , it definitely helps you score well despite it is a time consuming chapter.  You may find it boring in the beginning,  but it is in fact an easy chapter…!!

Current Electricity :

This is one of the easiest chapters and takes very less time to finish off. The basic concepts involved in this chapter are Ohm’s law and Kirchoff’s law. As it has equalently good weightage in IIT-JEE exam, solving many problems from this helps  a lot. While solving problems from this chapter, it is more useful when the mechanical analogy is kept in mind especially in RC circuits. In some cases, the RC circuits can be solved quickly, less than a minute if you are able to know the mechanical analogy suited. “Heating effect in electric current” is also an important concept.  When this concept is combined with thermodynamics, some good questions can be formed.

Magnetism :

Magnetism involves many applications from ‘Mechanics’ which is learnt in 11th standard. Many good questions can be formed on the concepts involving electric as well as magnetic  field.  The basic concepts in mechanics like kinematics, work energy theorem, law of conservation of linear momentum etc should be well versed. In most of the cases questions are asked from calculation of magnetic field in various cases.  Another important concept is the magnetic moment, on which many questions can be asked.  It is advised to practice many questions which involve the calculation of magnetic moment , basic idea of magnetic materials, explanation using magnetic moment etc. One more important topic is a loop in a uniform magnetic field which has many questions from this. From moving coil galvanometer also many good questions can be formed.

So guys..!! Focus on which helps you to score more and practice a lot on these areas to avoid mistakes and to get a better rank.

Wednesday, February 18, 2015

Nomenclature of Coordination Compounds

      Unable to write the nomenclature of coordination compounds? Here is an easy format to go through and learn how to name the coordination compounds correctly in a very less time..  
 1.      The ligand part is named first then the positive central metal atom is  named.
       2.      In the coordination sphere the name of the ligands is written alphabetically regardless of their charge followed by the metal.  
        Eg:- if the attached ligands are  (amine) and (aqua)  then first preference must be given to  as alphabetically amine comes before aqua.
            a)The name of the negative ligands ends with “-O”

    b)Neutral Ligands:

     c)Positive Ligands ends with - ium:

    4. The oxidation state of the central metal atom is shown by a roman numeral enclosed in brackets immediately following its name.
    5. Complex cations and neutral molecules have no special ending, but complex anions ends with “-ate”.

   6.In case of ambidenate ligands after the name of the ligand-Name of the atom through which it is attached to the central metal atom is written.


   7.In case of bridged ligand the bridged ligand is shown by the symbol  "" attached to metal atom.

        8.     While writing the name of complex don’t give spaces and write it in a single line without spaces .

Monday, February 16, 2015

What to focus in ELECTROMAGNETISM...?

Any guesses which topic in physics, forms a highly weighted section and major part for IIT-JEE..??
Its “ELECTROMAGNETISM” , which requires a lot of practice, understanding and skills to apply and solve the problems. To conquer this topic, the applications learnt in mechanics is going to help especially in the solving process.
The chapter wise analysis of the Electromagnetism can be made simpler by following the below analysis.

This topic has very fundamental things like coulombs law, principle of superposition, concept of electric field, electrostatic potential and many other basic topics of electromagnetism.  These basic topics should be understood thoroughly and practiced well. Simple questions asked from these topics in IIT-JEE can be answered easily with these concepts. “Conductors in Electrostatics” is one of the important topics in Electrostatics. The focus should be on the properties of conductors under electrostatic condition, as most of the questions in electrostatics are based on this concept. Practice of numerous questions from this topic is highly advised. Electrostatic flux and gauss law holds an equivalent importance in this chapter. These concepts can easily be correlated with other topics and are useful to solve many problems which are unrelated. In JEE, there is a question always asked involving the calculation of flux of a charge through some or the other surface. Thorough understanding of the concept and practice in this chapter surely helps to score well.

It is another simple but important topic chapters for IIT-JEE.  ‘Capacitors’ is the part of the application of electrostatics. This chapter can be found easy for those who have completed electrostatics thoroughly. There are some new concepts which are interesting and easily understood in this chapter . Capacitors is an important topic for Olympiads as well.  The next important concept in this chapter is the idea of dielectrics, on which a number of questions can be asked which involves the calculation of energy stored in capacitor/ electric field by capacitor etc which includes all the concepts of dielectrics. There are many questions asked on a capacitor with a dielectric where the dielectric constant varies as a function of position.

Thursday, February 12, 2015

How your habits affect you........

A wealthy man requested an old scholar to wean his son away from his bad habits.  The scholar took the youth for a stroll through a garden. Stopping suddenly he asked the boy to pull out a tiny plant growing there.
The youth held the plant between his thumb and forefinger and pulled it out. The old man then asked him to pull out a slightly bigger plant. The youth pulled hard and the plant came out, roots and all. “Now pull out that one,” said the old man pointing to a bush. The boy had to use all his strength to pull it out.
“Now take this one out,” said the old man, indicating a guava tree. The youth grasped the trunk and tried to pull it out. But it would not budge. “It’s impossible,” said the boy, panting with the effort.
“So it is with bad habits,” said the sage. “When they are young it is easy to pull them out but when they take hold they cannot be uprooted.”
The session with the old man changed the boy’s life.
Don’t wait for Bad Habits to grow in you, drop them while you have control over it else they will get control you.

Tuesday, February 10, 2015

Bernoulli's Theorem....

Ever thought of How can a plane fly?
 In a storm how does a house lose its roof?
Why do rabbits not suffocate in the burrows?
Why does a cricket ball swing or a baseball curve?
Here the answer is given by the bernoulli’s principle !

Bernoulli’s Equation:
Let us focus our attention on the motion of the shaded region. This its our “system”. The lower cylindrical element of fluid of length, A1 is at height y1 which moves with speed v1After some time, the leading section of our system fills the upper cylinder of fluid of length  and area  A2 at height y2, and is then moving with speed v2.

A pressure force F1 acts on the lower part of the cylindrical tube towards right and pressure force F2 acts on the upper part of the cylindrical tube towards left. The net work done on the system F1 and F2 is
Where we have used the relations   and. The net effect of the motion of the system is to raise the height of the lower cylinder of mass  and to change its speed. The changes in the potential and kinetic energies are
Since the density is, we have  .
Since the points 1 and 2 can be chosen arbitrarily, we can express this result as Bernoulli’s Equation   = constant               
It is applied to all points along a streamline in a nonviscous, incompressible and irrotational fluid.

In a storm how does a house lose its roof?
 Air flow is disturbed by the house. The "streamlines" crowd around the top of the roof.
faster flow above house
reduced pressure above roof to that inside the house
roof lifted off because of pressure difference.

Why do rabbits not suffocate in the burrows?
Air must circulate. The burrows must have two entrances. Air flows across the two holes is usually slightly different
slight pressure difference
forces flow of air through burrow.

One hole is usually higher than the other and the a small mound is built around the holes to increase the pressure difference.