1800-212-7858 (Toll Free)
9:00am - 8:00pm IST all days

or

Thanks, You will receive a call shortly.
Customer Support

You are very important to us

For any content/service related issues please contact on this toll free number

022-62211530

Mon to Sat - 11 AM to 8 PM

States Of Matter

Share this:

States of Matter PDF Notes, Important Questions and Formulas

States of Matter

Introduction to Gaseous State

A given substance may occur in solid, liquid or gaseous phase depending upon the relative value of two tendencies namely Mutual Attraction (MA) and Escaping Tendency (ET)

  1. If MA is greater than ET then substance will occur in solid state
  2. If MA is slightly greater than ET then substance will occur in liquid state
  3. If MA is very much less than ET then substance will occur in gaseous state

Out of the three states of matter, the simplest one is the gaseous state.

The state is characterized by sensitivity of volume change with change of pressure and temperature. It is due to large distance between molecules as compared to their own dimensions. There exist weak Vander Waal's forces, molecules move independent of each other with speed about 400 ms–1.

Gases show maximum equality in their behaviour irrespective of their nature.

2. Measurable properties of gases

1. Mass

Def.  The gases do possess mass. The mass of gas is generally used in the form of number of moles which is related as

(i) no. of moles

begin mathsize 12px style equals fraction numerator wt. text  in gm end text over denominator molecular text  mass of gases end text end fraction left parenthesis straight n equals straight w over straight M right parenthesis end style

Two other useful formulae to calculate number of moles of gas are-

(ii) number of moles

begin mathsize 12px style equals fraction numerator no. text   end text of text  molecules of given gas end text over denominator Avogadro apostrophe straight s text  number of molecules end text end fraction left parenthesis straight n equals straight N over straight N subscript straight A right parenthesis end style

(iii) no. of moles



<!DOCTYPE html>
<html>
<head><meta charset="UTF-8"><title>Error 500</title></head>
<body>
<h1>Error 500</h1>

<!--

-->



</body>
</html>

When container contain more than one gas then molecular mass of mixture is termed as effective molecular mass (EMM) which is intermediate between molecular mass (EMM) which is intermediate between molecular masses of all the gases present in the container.

Effective molecular mass

begin mathsize 12px style equals fraction numerator total text  number of all the gases present in the container  end text over denominator Total text  no.of moles of all gases present in the container end text end fraction end style

2. Volume

Def. Volume of gas is nothing but volume of the container in which it is present.

Relation between different units of volume

begin mathsize 12px style 1 text  m end text cubed text  = 10 end text cubed text  dm end text cubed equals text  10 end text cubed text  litre =10 end text to the power of 6 text  cm end text cubed text  = 10 end text to the power of 6 text  ml =10 end text to the power of 9 text   end text end exponent mm cubed end style

3. Temperature

Def. Degree of hotness or coldness of a body is measured by temperature

begin mathsize 12px style straight C over 100 equals fraction numerator straight K minus 273 over denominator 100 end fraction equals fraction numerator straight F minus 32 over denominator 180 end fraction end style

C – Celcius scale

K – Kelvin scale

F – Fahrenheit scale

Note: In all the problems of gaseous state (i.e in all gas law equations), temperature must be expressed in kelvin scale. i.e. ,

t℃+273=TK

4. Pressure

Def. Force acting per unit area

begin mathsize 12px style straight P equals straight F over straight A end style

Units:

          CGS           :          dyne/cm2

           MKS          :          Newton/m2

           Relation     :          1 N/m2=10 dyne/cm2

Units of pressure:

            1 atm = 76 cm of Hg

                        =760mm of Hg

                        = 760torr

                         =1.01325×105 N/m2

                          =101.325kPa

                         =1.01325 bar

                         =14.7 Ib/In2(Psi)

                          =10.33 meters of  H2o

5. Density

Def. Mass per unit volume

begin mathsize 12px style text d= end text straight m over straight v end stylebegin mathsize 12px style text d= end text straight m over straight v end style

Units:

  CGS: g/cm3

  MKS: kg/m3

  Relation: 1 kg/m3=10-3 g/cm3

Density of gases

Absolute density                                        Relative density

(Mass per unit volume)                          (Relative to hydrogen turned as vapour density)

  1. begin mathsize 12px style straight d equals straight m over straight v end style                                   (i) begin mathsize 12px style VD equals fraction numerator molecular text  mass end text over denominator 2 end fraction end style
  2. unit :  g/l                                 (ii) No unit
  3. Function of temp                      (iii)independent of Pressure, temperature

          Pressure, no. of moles

Note: Mass, volume and no. of moles are extensive

            Properties that depend on mass hence then all

             directly additive in nature.

Note: Density, pressure and temperature are intensive properties they does not depend on mass hence they are non-additive in nature.

3. The Gas Laws

(i) Boyle’s Law:

It relates the volume and the pressure of a given mass of a gas at constant temperature. Boyle’s law states that, “at constant temperature, the volume of a sample of a gas varies inversely with the pressure”.

begin mathsize 12px style therefore text   P end text proportional to 1 over straight v end style(When temperature and number of moles are kept constant)

The proportionality can be changed into an equality by introducing a constant k, i.e. ,

begin mathsize 12px style straight P equals straight k over straight V text  Or PV=k end text end style

Boyle’s law can be verified by any one of the following three ways graphically.

Alternatively, Boyle’s law can be stated as follows:

“Temperature remaining constant, the product of pressure and volume of a given mass of a given mass of a gas is constant”.

The value of the constant depends upon the amount of a gas and the temperature.

Mathematically, it can be written as.

begin mathsize 12px style straight P subscript 1 straight V subscript 1 minus straight P subscript 2 straight V subscript 2 minus straight P subscript 3 straight V subscript 3 minus. ....... end style

(ii) Charles’ Law:

It relates the volume and temperature of a given mass of a gas at constant pressure.

For each degree change of temperature, the volume of a sample of a gas changes by the fraction begin mathsize 12px style 1 over 273 end styleof its volume 0℃.

Let the volume of a given amount of gas be at 0℃ . The temperature is increased by t℃ and the new volume becomes Thus,

 begin mathsize 12px style straight V subscript straight t equals straight V subscript 0 plus straight V subscript 0 over 273 cross times straight t equals straight V subscript 0 left parenthesis 1 plus straight t over 273 right parenthesis end style

Orbegin mathsize 12px style straight V subscript straight t equals straight V subscript 0 left parenthesis fraction numerator 273 plus straight t over denominator 273 end fraction right parenthesis end style


Solid State

Solid

Liquid

Gas

  1. Have definite volume

Have definite volume

Have indefinite volume

  1. Their shape is fixed

Their shape is indefinite volume

Their shape is indefinite

  1. They have strongest

Intermolecular attraction. Hence their shape as well as volume is fixed

Their force of attraction is intermediate between solids and gases. So shape is variable but volume is fixed.

They have very weak force of attraction. Hence molecules are very-very loosely connected with other and hence have neither shape nor volume

The outstanding macroscopic properties of gases are compressibility and fluidity. In contrast, the most noticeable macroscopic features of crystalline solids are rigidity, incompressibility and characteristic geometry. We shall find that the explanation of these macroscopic properties in terms of the atomic theory involves the idea of lattice: a permanent ordered arrangement of atoms held together by forces of considerable magnitude.

Thus the extremes of molecular behaviour occur in gases and solids. In the former we have molecular chaos and vanishing intermolecular forces, and in the latter we have an ordered arrangement in which the interatomic forces are large.

Types of Solids

(a) Crystalline solids: In a single crystal the regularity of arrangement of the pattern extends throughout the solid and all points are completely equivalent.    

(b) Amorphous solids: An amorphous solid differs from a crystalline substance in being without any shape of its own and has a completely random particle arrangements, i.e. no regular arrangement. Example: Glass, Plastic

Classification of crystalline

Molecular solids: Those solids which consists of small molecules are called molecular solids.

(1)Non - polar molecular solids: (electronegativity sequence (F > O > N . Cl > Br > S > C . H)

The solids which have zero dipole moment are called non-polar molecular solids. The molecules are held together by weak Vander waal’s forces. Hence they are either gas or liquids at room temperature.

They are poor conductor of electricity due to their non-polar nature.

(2)Polar molecular solids:

Those solids which have non-zero dipole moments are called polar molecular solids. Polar molecular solids have dipole - dipole interaction, which is slightly stronger than vander waal’s force and hence they have larger melting and boiling points than the non - polar molecular solids.

Example: Solid CO2, Solid NH3

They are generally liquids or gases at room temperature.

(3) Hydrogen bonded molecular solids:

Those molecular solids which are bonded with each other by hydrogen bonds are called hydrogen bonded molecular solids.

Example: Ice

They are non-conductor of electricity

Generally they are liquid at room temperature or soft solids.

IONIC SOLIDS: All those solids whose constituent particles are ions are called ionic solids,

Example: NaCl, CsBr, AgBr, CsCl

METALLIC SOLIDS:

All those solids which are bonded by metallic bonds are called metallic solids. Inner core electrons are immobile Metallic solids show a great electrical conductivity due to availability of large number of free electrons whose movements constitute electric current. Metallic solids are malleable and ductile. Metallic solids have lustre. Metallic solids have good thermal conductivity.

COVALENT SOLIDS OR NETWORKED SOLIDS:

Whenever electric field is applied, electrons move between the layers. Graphite is a good conductor of electricity due to availability of free electrons. Networked solids are hard and brittle. Carbon - carbon bond has got partial double bond character in graphite. Two layers in graphite are attached with each other by weak vander waal force. Graphite can be used as a lubricant at high temperatures.

What is a crystal?

A crystalline solid consist of a large number of small units, called crystals, each of which possesses a definite geometric shape bounded by plane faces. The crystals of a given substance produced under a definite set of conditions are always of the same shape.

Unit Cells

In this topic we would be studying certain properties of a solid which depend only on the constituents of the solid and the pattern of arrangement of these constituents. To study these properties, it would be convenient to take up as small amount of the solid as possible because this would ensure that we deal with only the minimum number of atoms or ions. This smallest amount of the solid whose properties resemble the properties of the entire solid irrespective of the amount taken is called a unit cell. It is the smallest repeating unit of the solid. Any amount of the solid can be constructed by simply putting as many unit cells as required.

Bravais Lattices

Bravais (1848) showed from geometrical considerations that there are only seven shapes in which unit cells can exist. These are:

  1. Cubic
  2. Orthorhombic
  3. Rhombohedra
  4. Hexagonal
  5. Tetragonal
  6. Monoclinic
  7. Triclinic.

Moreover he also showed that there are basically four types of unit cells depending on the manner in which they are arranged in a given shape. These are: Primitive, Body Centered, Face Centered and End Centered. He also went on to postulate that out of the possible twenty eight unit cells (i.e. seven shapes * four types in each shape = 28 possible unit cells), only fourteen actually would exist. These he postulated based only on symmetry considerations. These fourteen unit cells that actually exist are called Bravais Lattices.

Show more

IIT-JEE Tests & Papers Solutions

Chemistry syllabus

Purchase Our Experts Course Packages

Enroll now to crack IIT-JEE

Testimonials

Ask Experts for IIT-JEE

Queries asked on Sunday and after 7 pm from Monday to Saturday will be answered after 12 pm the next working day.

Chat with us on WhatsApp