1.0 CONCEPT OF MATTER

1.1 INTRODUCTION

   Every object on the surface of the earth is made of minute particles called atoms which date back to ancient Greeks. According to the Greek Philosopher, Democritus, a given piece of substance, such as a piece of apple can be cut into smaller and smaller bit, until eventually the smallest piece of substance would be obtained which could not further divided.

1.2 MATTER

   Matter is defined as anything that has weight and occupies space. Matter exist in three state namely: Solid, Liquid , Gaseous state. Example of solid is "ice", Liquid is "water", Gaseous is "steam". Other example of solid are "Brick, Metal, Wood" Other example of liquid are "Milk, Oil", Other example of Gaseous are "Oxygen, Nitrogen, Carbon dioxide".

1.3 EVIDENCE OF THE PARTICLE NATURE OF MATTER

   Brownian Motion (Movement): Is the evidence that molecules exist in matter and that the molecules are continually in motion. This makes us look considerably at smoke. When a burning fire is kindled or lighted, smoke is seen move upward into the sky.
   Brownian's conclusion, therefore was that (i) Molecules are continually in motion (ii) Molecules exist.

1.4 SIMPLE ATOMIC STRUCTURE

   Atom is made up of particles, namely (Proton, Electron, Neutron). Proton and Neutron are found in a closely-packed nueleus. Proton is +ve charge, Electron is -ve charge, Neutron is neutral.
   Electron revolves round the nucleus, while proton and neutron from the main nucleus of the atom. The electron outside the nucleus is at a relatively far distance from it.The charges proton carried by (+ve) and mass is 1 and the charge carried by electron is (-ve) and mass is 1/1840, Neutron has no charge and the mass is 1.

   MOLECULE

   Molecule are very tiny particles which, when they come together, make up matter.Molecule themselves are made up of atoms. The energy possessed by molecules is of two kinds (i)Kinetic Energy (ii) Potential Energy.

   KINETIC THEORY OF MATTER

   According to the Kinetic theory of matter, every substance consist of very large number of very small particles called molecules. These molecules, which are made up of atoms are the smallest particles of a substance that can exist in a free state. The kinetic theory is based on the following;

   (i) Matter is made up of molecule
   (ii) Molecule are in rapid motion
   (iii) Molecules experience forces of attraction i.e they are attracted, one another.

   SIZE OF MOLECULE

   To determine the size of a molecule, oil is spread in drops over a surface of clean water in a container. Lycopodium or talcum powder can be used to dust the surface of the water, so as to show clearly where exactly the oil is, i.e the powdery surface will be drawn back as the oil spread.

   Taking the volume of oil as A1 cm3 and the area of the surface covered by the oil as A2 cm3, The volume of oil drop = Volume of oil form. i.e 4πr3/3 = πr2h

1.5 GENERAL PROPERTIES OF MATTER

   The properties of matter which are common to all substances are as follow;

   (1) matter is made up of tiny particles, molecules or atoms
   (2) matter occupies space
   (3) matter possess inertia, mass or weight.
   (4) matter expert pressure.

   SOLID STATE
   >> Has Definite shape
   >> Has definite volume
   >> It is tightly packed

   LIQUID STATE
   >> Has no definite shape
   >> Has definite volume

   GASEOUS STATE
   >> Has no shape
   >> Has no volume

1.6 MOLECULAR THEORY OF MATTER

   1. SOLID: The intermolecular distances are small and the forces of intermolecular attraction are large. Hence; a solid has definite shape and size. Heating a solid means giving more energy to the molecules. This enable the molecules to liberate themselves more violently from their mean positions. The molecule further move apart, resulting in the expansion of the solid.

   2. LIQUID: Molecules are further apart than solid. The molecule are not confined to any fixed position. They are free to move about within the given volume of the container. Hence; Liquid ha it own size but no shape. The molecule are always in state of random motion. They collide with one another and they may or may not change their respective kinetic energy when the liquid is heated.

   3. GASEOUS: The intermolcular distances are much longer and larger than that of solid or liquid and the molecules of gases are free to move about the entire space which is available to them. Hence; a gas has no definite shape and size. Molecules possess rapid random motion and the forces of intermolecular attraction are negligible.

1.7 MOLECULAR FORCES

   A. Adhesive forces: are forces which make molecules of different substance to attract. and it occurs on water in a glass cup.

   B. Cohesive forces: are forces which makes molecules of the same substance to attract. and it occurs in the case of mercury put in a glass.

1.8 DIFFUSION

   This is the process by which different forms of matter (fluid) mix intimately with one another owing to the kinetic nature of their particles or molecules.

   Factors affecting Diffusion

   >> Density
   >> Temperature
   >> Pressure
   >> Concentration
   >> Mass

   GRAHAM'S LAW OF DIFUSION

   Graham observed the speed at which molecules move about inside a gas this formed the basis of a law called the Graham's law of diffusion Thus, Graham's Law Of Diffusion states that at constant temperature, gases diffuse at rate which are inversely proportional to the square root of their vapour densities.

   r ∝ 1/(M)½

or

r(M)½ = constant

In these equations, r = rate of diffusion or effusion and M = molar mass.

Generally, this law is used to compare the difference in diffusion and effusion rates between gases, often denoted as Gas A and Gas B. It assumes that temperature and pressure are constant and equivalent between the two gases. When Graham's law is used for such a comparison, the formula is written as follows:

rGas A/rGas B = (MGas B)½/(MGas A)½

1.9 OSMOSIS

   Osmosis is the movement of water molecules from a region of higher concentration to a region of lower concentration through a semi-permeable membrane.

 

 [1] Proton, Neutron and Electron are the main composition of an atom. Discuss
 [2] Explain Brownian motion
 [3] What is matter
 [4] Explain the 3 states of matter
 [5] Describe the relationship that exist among the 3 state of matter
 [6] Explain Kinetic theory of matter
 [7] What is Adhesive force
 [8] What is Cohesive force
 [9] What is difussion
 [1o] What is Osmosis
 [11] State the similarities among the 3 state of matter
 [12] State the factors affecting the rate of diffusion
 [13] State the properties of matter common to all substances
 [14] Differentiate btw Solid and Liquid
 [15] Give 2 examples of Solid , Liquid and Gas

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[Physics I] Introduction And Concepts Of Matter (PDF)