States of matter

1. Unit 1
Concepts of Chemistry

2. Why do we need
chemistry?

3. IMPORTANCE
 Principles of chemistry are applicable in diverse areas, such as
production in chemical industries, manufacturing fertilizers,
alkalis, acids, salts, dyes, polymers, drugs, soaps, detergents,
metals, alloys, etc.
 It also plays an important role in meeting human needs for food,
healthcare products and other material aimed at improving the
quality of life.

4. Forensic chemistry
 Sub-discipline of forensic science.
 Applies the principles of chemistry in the analysis of the evidences, in order to provide justice
in a legal setting.
 Some of the common applications:
 Drug analysis using Spectroscopy, chromatography.
 Arson cases
 Examination of petroleum products.
 Examination of inks, paints, dyes and other colouring agents.
 Analysis of firearm, explosive and arson residues.
 Examination and identification of trace metal elements.
 Examination and identification of volatile and flammable materials especially found in
suspected cases of arson cases.
 Identification of adulteration in concrete, bricks and other building materials.

5. Let’s start from
the scratch!!

6. Matter: Anything that has mass and occupies space is called a matter

7. PROPERTIES OF MATTER
 Physical properties
 Chemical properties

8. Measurement of Physical Properties
Quantitative measurement: Many properties of matter, such as length, area,
volume, etc., are quantitative in nature. Any quantitative observation or
measurement is represented by a number followed by units in which it is measured.
 Mass
SI unit -Kg
analytical balance is used
 Weight
 Volume
SI unit of volume is the cubic meter (m3)
the volume of liquids or solutions can be measured by graduated cylinder,
burette, pipette, etc.
A volumetric flask is used to prepare a known volume of a solution.

9. Density
Density Meters
SI unit kg/m3
 Temperature
Thermometer
SI unit is K
Other 2 scales- °C (degree celsius), °F (degree Fahrenheit)
Conversions

10. States of matter
 Exist in three physical states- solid, liquid and gas.
 Arrangement of particles in solid , liquid and gas.
 Based on the arrangement of particles, different states of matter exhibit
the following characteristics:
 Solids have definite volume and definite shape.
Liquids have definite volume but do not have definite shape. They
take the shape of the container in which they are placed.
Gases have neither definite volume nor definite shape. They
completely occupy the space in the container in which they are
placed.

11. Intermolecular forces
 Forces of attraction and repulsion between interacting particles (atoms and
molecules).
 Attractive intermolecular forces are known as van der Waals forces, in honour
of Dutch scientist Johannes van der Waals
 Attractive forces between an ion and a dipole are known as ion-dipole forces
and these are not van der Waals forces
1. Dispersion forces
 Force of attraction between two temporary dipoles is known as London force.
Another name for this force is dispersion force
 Atoms and nonpolar molecules are electrically symmetrical and have no dipole
moment
 These forces are always attractive and interaction energy is inversely
proportional to the sixth power of the distance between two interacting particles

12. 2.Dipole - Dipole Forces
 act between the molecules possessing permanent dipole
 This interaction is stronger than the London forces but is weaker than
ion-ion interaction because only partial charges are involved
 The attractive force decreases with the increase of distance between
the dipoles.

13. 3.Dipole–Induced Dipole Forces
 Attractive forces operating between the polar molecules having
permanent dipole and the molecules lacking permanent dipole.
 Permanent dipole of the polar molecule induces dipole on the
electrically neutral molecule by deforming its electronic cloud .Thus
an induced dipole is developed in the other molecule.
 Interaction energy is proportional to 1/r 6 where r is the distance
between two molecules

14. 4.Hydrogen bond
 This is special case of dipole-dipole interaction.
 Only a few elements can participate in hydrogen bond formation,
therefore it is treated as a separate category
 found in the molecules in which highly polar N–H, O–H or H–F bonds
are present.
 hydrogen bonds are powerful force in determining the structure and
properties of many compounds, for example proteins and nucleic acids.
 Strength of the hydrogen bond is determined by the coulombic
interaction between the lone-pair electrons of the electronegative atom
of one molecule and the hydrogen atom of other molecule.

15. Why are solids and liquids hard to
compress?
 When two molecules are brought into close contact with each other,
the repulsion between the electron clouds and that between the
nuclei of two molecules comes into play. Magnitude of the
repulsion rises very rapidly as the distance separating the molecules
decreases
 In these states, molecules are already in close contact; therefore
they resist further compression; as that would result in the increase
of repulsive interactions.

16. THERMAL ENERGY
Directly proportional to the temperature of the
substance
Energy of a body arising from motion of its atoms or
molecules
Thermal motion.