Atomic Theory of Matter

Anything that has mass and takes up space is a matter. For examples, stone, wood, and concrete are matter. Things, such as sound and wave are not matter. Atomic theory of matter had been announced that matter consists of fine discrete particles. These fine particles are discrete and existent separately among them. These fine particles can exist as atom, molecule or ion.

Atom is the smallest neutral particles in an element. Neutral particle is the particle that without any charge either positive or negative charge. Element is a pure substance that contains one type of atom only. It also can not be divided to simpler substances. For an example, 100% pure iron block contains only iron atoms.

Compound is formed by chemical reaction through association or combination of two or more elements. Chemical bond must have been formulated among the elements in the compound. If the elements do not form any bond, they are only a mixture. Molecule is a neutral particle that is formed through chemical association or combination of two or more atoms either similar or different type of atom.

Chlorine is a molecule, which has the same type of atom; whereas methane is a molecule, which has different type of atom. Two chlorine atoms form bond with each other; whereas, carbon atom in methane forms four bonds with four hydrogen atoms.
Ion is a particle contains either positive or negative charge. It forms after the electrons in an atom or molecule have been transferred to other destination or from other destination into the atom or molecule. Due to the transferring of electrons inside the atom and molecule, the atom and molecule may be in unbalanced charge situation. If the atom and molecule are in excess of electron, they become negatively charged. Contrary, if they in an electron deficiency situation, they become positively charge. Anion is the term for the atom or molecule that is negatively charged; whereas cation is the term for positive charge atom and molecule. Examples for the cation are Mg2 +, Ca2 +, Na +, Fe3 + and examples for anion are SO42-, NO3-, PO43-, Cl-

Matter consists of fine particles that always move randomly. Evidence that can support the matter kinetic theory is the diffusion process. Following is an experiment to estimate the olive oil particle size.

Part A: Determination of the volume of a drop of oil
Fifty drops of olive oil are dripped into the beaker from the burette. Volume for the fifty drops of oil can be obtained from the burette by deducting the final volume to initial volume of the burette. Volume for one drop of olive oil can be obtained by dividing the volume of the fifty drops of olive oil with fifty. Calculation of the volume for one drop of olive oil is as follow:

Initial volume before dripping 50 drops of oil = x cm3

Final volume after dripping 50 drops of oil = y cm3

Volume of 50 drops of oil = (yx) cm3

Volume for one drop of oil = (yx) / 50 cm3

Part B: Determination of the number of small drop of oil that can be separated from a drop of oil, which is stripped from the burette
A drop of oil, which is dripped from burette, is too big to drip on the surface of water with a thin layer of lycopodium powder covers on it. Therefore, drop of oil from burette has to be separated again to a smaller drop of oil. The number of small drop of oil that can be separated from the big drop of oil (from burette) can be determined by transfering the oil from the watch glass to the filter paper using sharp tip glass rod. A small drop of oil is adhered to the sharp tip and is transferred to the filter paper. The filter paper is a high oil absorption material. In such a way, it can absorb most of the oil, which adheres to the sharp tip glass rod. From the number of small drop oil that has been transferred to the filter paper, volume of small drop of oil can be calculated by dividing the volume of big drop of oil from burette to the number of transferring. The calculation is as follow:

Volume of the big drop of oil that is dripped from the burette has been determined as (yx) / 50 cm3 in the part A.

Volume of the small drop of oil that adheres on the sharp tip of the glass rod = volume of the big drop of oil on the watch glass divides by the number of transferring times. Equation for the calculation is as follow:

Volume of the small drop of oil that adheres to the sharp tip of the glass rod =

(yx) / 50n

Where n = number of transferring times for the small drop of oil from the watch glass to the filter paper.

Part C: Determination the area of ​​the oil spot on the surface of the water
When a small drop of oil that adheres to the sharp tip of the glass rod is dripped on the surface of the water with a thin layer of lycopodium powder covers on it, the oil will push the lycopodium powder to the edge of the tray. Diameter of the forming spot can be measured using ruler. This value can be used to calculate the surface area of ​​the oil spot. The calculation is as follow:

We represent oil spot diameter as d cm.
Surface area of ​​the oil spot on the water surface = surface area of ​​a circle = j2 =  (d / 2) 2 cm2

Part D: Estimating the size of an oil particle
Size of the olive oil particle can be calculated as follow:

Thickness of the oil layer is represented as t cm.
Volume of oil spot in the form of cylinder =  (d / 2) 2 t cm3
Due to the volume of the oil spot on the surface of water is equal to the volume of a small drop of oil, which is transferred from the watch glass. Therefore,

 (d / 2) 2 t cm3 = V

=>  (d2 / 4) t = V

=> t = (4V / d2) cm

By assuming oil spot on the surface of the water consists of only a layer of particles. So,
Size for an oil particle, t = (4V / d2) cm
Value that normally obtained is around 10-7 cm. This indicated that size for an oil particle is very small.

Beside, precaution steps that need to be taken in order that the obtained result is more accurate and accurate are as follow:
(i) Water in the tray must stable before the lycopodium powder is scattered on top of it.

(ii) Layer of the lycopodium powder on the water surface must as thin as possible and equilibrium.

(iii) Tray and the water in it must be free from any oil stain and dirt that will affect the equilibrium of the oil spot.



Source by Jame Chong

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