DIFFERENCE BETWEEN TEMPERATURE AND HEAT

 DIFFERENCE BETWEEN TEMPERATURE AND HEAT:

•TEMPERATURE:

The measure of average kinetic energy of all the particles of a system is called temperature.

It represents the kinetic energy of the molecules of the system.

It is independent of the quantity of the substance.

It is measured without the help of heat.

It is a state function.

•HEAT:

The property which flows from the hotter part of the body to the cooler part is called heat.

It is the measure of total energy in a given amount of substance.

It depends upon the quantity of the substance.

It is measured with the help of temperature.

It is not a state function because it is not the property of system.

HAIR DYE

 HAIR DYE:

•RAW MATERIAL:

In general,hair dyes include:

1. Dyes e.g 4-amino-2-hydroxytoluene

2. Modifiers e.g.resorcinol

3. Antioxidants e.g. sodium sulfite

4. Alkalizers e.g. ammonium hydroxide

Beyond these chemicals, many different chemical are used to impart special qualities. They may be shampoos, fragrances, chemicals that make the formula creamy,foamy,or thick, or contribute to the overall action of the formula.

•DIFFERENT TYPES OF HAIR DYE:

There are three types of hair dyes.

•Permanent: Causes some lightening of hair, contains 3-6% hydrogen peroxide, contains oxidative dyes that form during application, does not wash out significantly but may fade.

•Semi-permanent: causes mild lightening of hair, contains 1-2% hydrogen peroxide, contains oxidative dyes that form during application, last around 6 weeks.

•Temporary  dye(direct dye): no lightening of hair, does not contain peroxide, contains dye that are already formed before application, washes out in a few washes.

DIFFERENCE BETWEEN VALENCE BOND THEORY AND MOLECULAR ORBITAL THEORY

 DIFFERENCE BETWEEN VALENCE BOND THEORY AND MOLECULAR ORBITAL THEORY:

•VALENCE BOND THEORY:

(1)Only Valence shell electrons are involved in bond formation.

(2) The two concerned atoms don't lose their individual identity.

(3) It doesn't explain the Para magnetic behaviour of molecules.

(4) It doesn't give idea about bond order.

(5) It doesn't explain the non existence of He2 molecule.

•MOLECULAR ORBITAL THEORY:

(1) All the electrons of interacting atoms are involved in bond formation.

(2) The two atoms lose their individual identity.

(3) It explain the Para magnetic behaviour.

(4) It give idea about bond order by which we can determine that whether the bond is single, double or triple.

(5) It explain the non existence of He2 molecule.

Adsorption chromatography*and Column chromatography

 *Adsorption chromatography*

The chromatographic separation of the components in a mixture by absorption from a mobile liquid stream onto the surface of a powdered solid as a stationary phase is called adorption chromatography

*Column chromatography*

It is a type of adsoprtion chromatography.

Basic principle:

The principle behind column chromatography is adsorption, in which a mixture of components dissolved in the mobile phase is introduced in to the column and the components move depending on their relative affinities.

Factors:

The experiment factor of column chromatography are (I) the nature of adsorbent ..( ii ) the nature of solvent  ( iii ) the operating parameters 

1.. nature of adsorbent 

An adsorbent is usually a finely divided solid possessing an extremely large surface area . The characteristics of a solid that must b considered when selecting an adsorbent to effect the chromatographic seprations are ..

1  surface area ___ preferably 50m^2/g 

 2.  Particle size 100 -200 mesh (150-75) provide a minimum resistance to flow

3.  Surface activity --- higher surface activity of adsorbent will lower the separation efficiency..

2.. Nature of solvent 

The solvent in which a sample is dissolved will complete with the components of the sample for surface sites upon which to b absorbed . A solvent which is strongly adsorbed in the surface will act as a strong eluent and will displace solutes easily and thus results in shorter retention time of solutes

3.. Nature of solute

The most important feature of an adsorbent chromatography separation is the extent of separation of the components of the solute sample for a given solvent adsorbent system 

4.. Operating parameters.

The effect of general experimental conditions such as method of packing , flow rate and temperature are important for the effiency of a column adsorption 

(a) packing

Technique if column packing is important . One common method is to pour dry powered solid slowly onto the top of the glass column . The column is gently tapped or vibrated till the solid settles

(b) Flow rate

The rate of flow rate of solvent through the column is very important in achieving successful chromatographic seprations . If the flow rate is too rapid , there will b issuffient time for the adsorption..

(c) Temperature

Increasing the temperature of the column will cause a slight decrease in the adsorption of all the components into sample  . This decrease is on the order of 1-2% per degree centigrade

Differences between Fission and Fusion reaction

*Nuclear fission* 

1- Heavy nuclei split into lighter nuclei of comparable atomic masses

2- nuclei of heavy elements undergo fission

3- The reaction initiates at normal temperature

4- The fission process liberates about 200 MeV energy

5- Fast neutrons are also released

6- Fuel is either solid or liquid 

*Nuclear fusion..*

1- lighter nuclei fuse to form heavy nuclei

2- nuclei of light elements are in involved in the process of fusion

3- Fusion initiates at 10^8 K

4- the energy released in 24 MeV

5- nature of the ejected particles depends uopn the type of thermonuclear reaction

6- Fuel is in plasma state

DEFFECTS OF BOHR'S ATOMIC MODEL

 DEFFECTS OF BOHR'S ATOMIC MODEL:

◉MONO-ELECTRONIC SYSTEM:

Bohr's theory can not explain the origin of the spectrum of multi electrons or poly electronic system like He, Li,Be. 

◉HIGH RESOLVING SPECTROMETER:

When a spectrum of hydrogen gas is seen through a powerful spectrometer, the original spectral lines are replaced by several very fine lines i.e, original lines are divided into other fine lines. These lines cannot be explained by Bohr's theory. 

◉THREE DIMENSIONAL MOTION OF ELECTRONS: 

Bohr suggested circular orbits of electrons around the nucleus of H-atom. But it is proved that the motion of electrons is not in a single plane but takes place in three dimensional space. 

◉ZEEMAN EFFECT:

When the excited atoms of hydrogen giving atomic emission spectrum is placed in a magnetic field, it's spectral lines further split up into closely spaced lines. This type of splitting up of spectral lines is called "Zeeman effect".Bohr's theory doesn't explain zeeman effect. 

◉STARK EFFECT:

When the excited hydrogen atom giving atomic emission spectrum is placed in a strong electric field, its spectral lines further split up into closely spaced lines. This type of splitting up of spectral lines is called " stark effect". Bohr's theory doesn't explain stark effect

Le Chatelier's principle

                Le-chatlier Principle

Defination: If you imppose a change on a system that is at equilibrium system behave in a way as to oppose that change.

Change in concentration :If concentration of reactant is increased reaction will move in farward direction towards product to nuteralize the effect of that change. 

If concentration of product is increased reaction will move in backward direction. For example consider a reversable reaction 

H2 + I2  <=====> 2HI 

In this reaction if concentration of Hydrogen and Iodine is increased reaction will move in farward direction.

Change in pressure :

If pressure is increased reaction will move towards less volume side (less no of mole side).If pressure is decreased reaction will move towards greater volume side(more no of mole side).

N204    <=====>  2NO2 H= +57.2

In this reaction prooduct have 2 moles and reactant have 1 mole since volume is directly proprtional to no of moles and inversly proportional to pressure .hence increase in pressure will move reaction towards backward direction.

If no of moles of both ractant and product are same pressure change will not effect eqilibrium .

H2 + I2  <=====> 2HI

Change in Temperature:

Reaction is of two types exothermic (Heat is released -ve sign)  or endothermic (heat is absorbed+ve sign).

If reaction is exothermic increase in temperature will move reaction in backward direction and vice versa

If reaction is endothermic Increase in temperature will favour farward reaction . 

For example consider the following reaction 

N204 <=====> 2NO2 H= +57.2

+ve sign show it is an endothermic reaction.If we increaese temperature reaction will move in farward direction.

This vedio will be helpfull in understanding the most important topic buffer solution.

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