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Author Topic: [Chemistry] Introduction To Chemistry And Possible Questions  (Read 231 times)

Offline Mr. Babatunde

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1.0 INTRODUCTION TO CHEMISTY

   Chemistry is one of the three main branches of pure science, the other two being Biology and Physics.
Chemistry deals with the composition, properties and usues of matter. It probes into the principles of govering the changes that matter undergo.

2.0 SUMMARY (NATURE OF MATTER)

    * Matter is anything that has mass and ocupy space.
    * The mass of an object is the quantity of matter that the object contains.
    * Matter is built up of one or more of the three elementary particles (Atoms, Molecules & Ions).
    * Matter exist in three states (I) SOLID (II) LIQUID (III) GAS.
 
 2.1 MATTER UNDERGOES CHANGES

    (I) A physical changes is one which is easily reversibe and in which no new substances are formed.
    (II) A chemical changes is one which is not easily reversible and in which new substance are formed.

 2.2 MATTER CLASSIFIED INTO

    * ELEMENT: a substance which cannot be split into simpler unit by ordinary chemical processes.
    * COMPOUND: a substance which contain two or more element chemically combined together.
    * MIXTURE: contains two or more constituent which can easily be seperated by physical methods.

 2.3 METHOD OF SEPERATING MIXTURE
 
  [a.] Sieving: To seperate solid particles of different sizes.
  [b.] Magnetic seperation: To seperate magnetic solids from non-magnetic ones.
  [c.] Sublimation: To seperate solid which sublime from other solid.
  [d.] Decantation: To seperate insoluble solid from a liquid.
  [e.] Filtration: To seperate insoluble solid from a liquid too.
  [f.] Centrifugation: To seperate insoluble solid from a liquid.
  [g.] Evaporation: To seperate soluble solid from a solution.
  [h.] Crystallization: To seperate soluble solid from a solution.
  [i.] Precipitation: To seperate soluble solid from a solution.
  [j.] Distillation: To seperate solvent from its solution.
  [k.] Fractional Distillation: To seperate miscible liquids.
  [l.] Seperating funnel: To seperate immiscible liquids.
  [m.] Chromatography: To seperate solutes from solutions.

 2.4 APPLICATION METHODS OF SEPERATING MIXTURES

    [ Sieving - in mining indusrties ]
    [ Filtration - in water purification plants ]
    [ Evaporation - in salt-making industries ]
    [ Distillation - in making gin and distilled water ]
    [ Fractional distillation - in petroleum industry ]
    [ Crystallizaion - in sugar & drug manufacture ]
    [ Chromatography - as a tools in the indentification & analsis of substance ]


 Seperation tecniques can be used to obtain sample of pure substances. The purity can be easily checked by determining their melting point (for solid) or their boiling points for liquids.


2.5 DIFFERENT BTW PHYSICAL & CHEMICAL
   
   [A.] Phsyical Changes

   * It is easily reversible.
   * No new substances are formed.
   * There is no changes in the mass of a substance.
   * It does not involve any great heat changes.

   [B.] Chemical Changes

   * It is not easily reversible.
   * Entirely new substances are always produced.
   * There is a changes in the mass of a substance that undergos such a changes.
   * A considerable amount of heat changes is usually involved.

2.6 COMPARISON OF MIXTURE & COMPOUNDS

   [A.] MIXTURE

   * It maybe homogeneous and heterogenous.
   * The constituents are not chemically bond together and can be seperated by physical means.
   * The constituent can be added together in any ratio by mass.
   * The properties of a mixture are the sum of those of its individual constituents.

   [B.] COMPOUNDS

   * It is always homogeneous.
   * The component elements are chemically bond together and cannot be seperated by physical means.
   * The components are presents in a fixed ratio by mass.
   * The properties of a compound differ entirly from those of its component elements.


2.7 COMPOUND AND THEIR COMPONENTS

   Water = Hydrogen, Oxygen (H2O)
   Sand = Silicon, Oxygen (SiO2)
   Limestone = Calcium, Carbon, Oxygen (CaCO3)
   Common Salt = Sodium, Chloride (NaCl)
   Sugar = Carbon, Hydrogen, Oxygen (C12H22O11)
   Ethanol = Carbon, Hydrogen, Oxygen (C2H5OH)
   Washing soda = Sodium, Carbon, Oxygen, Hydrogen (Na2CO3.10H2O)
   Hard soap = Sodium, Hydrogen, Carbon, Oxygen (C17H35COONa)
   Caustic soda = Sodium, Oxygen, Hydrogen (NaOH)

POSSIBLE QUESTIONS


[1] What is chemistry ?
[2] what is matter ?
[3] Matter is built up of how many particles & list them ?
[4] What is the states matter exist ?
[5] What is an element ?
[6] Give 7 element you know ?
[7] Matter undergos how many changes & List them ?
[8] Diffreciate btw Compound and Mixture
[9] What is a compound ?
[10] What is physicial & chemical changes ?
[11] What is a mixture ?
[12] Differenciate btw Physical & Chemical changes
[13] What is seperation techniques ?
[14] List and Explain all seperation techniques you know
[15] What is the Component for this compound (I) Hard soap (II) Ethanol
[16] What application of the method of seperating mixtures is (I) Seiving (II) Evaporation ?
[17] What compound is H20 and NaCl
[18] Give uses of the two compound in QUE 17
[19] Solid which sublime from other solid is what ?
[20] Give examples of SOLID , LIQUID AND GAS

[Chemistry] Introduction To Chemistry And Possible Questions (PDF)












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