Paktruk.. nazish


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Paktruk.. nazish

  1. 1. What Is Chemistry  The branch of science deals with the composition structure , properties and the reactions of the matter
  2. 2. Different branch of chemistry  Physical chemistry  Organic chemistry  Inorganic Chemistry  Biochemistry  Industrial Chemistry  Environmental Chemistry
  3. 3. Basic Definitions Matter: Any thing that have mass and occupies space
  4. 4. Substance : A piece of matter in pure form Mixture: Impure matter is called mixture. Element: It is substance made up of same type of atoms, having same atomic number and it can not be decomposed in to simple substance by ordinary chemical means. Examples O2 , H2 etc
  5. 5.  Substance made up of two or more elements chemically combine together in a fix ratio by mass. e.g. NaCl, H2O etc.
  6. 6. Mixture When two or more elements or compounds mix up physically without any fixed ratio. Types of Mixture •Homogeneous :same composition Examples ice cream, air, gasoline
  7. 7. •Heterogeneous: different element mix together : Examples: Rock, soil and wood etc
  8. 8. Atomic number and atomic mass Atomic number of an element is equal to the proton present in the nucleus of its atom. It is represented by Z. Mass number Mass number is a sum of number of protons and neutrons present in the nuclease of an atom. It is represented by A. A= Z+n n is the number of neutrons
  9. 9. Empirical formula Simplest whole number ratio of atoms present in a compound.e.g CH is the empirical formula of benzene and its chemical formula is C6H6. Molecular formula Actual number of atoms of each elements present in a molecule of a compound. Molecular formula derived from empirical formula e.g. C6H12O6 and its empirical formula is CH2O
  10. 10. Chemical Species: Ions: is a atom or group of atom having charge on it. The charge may be positive or may be negative Cation :any atom or group of atom having positive charge on it e.g.
  11. 11. Anion: Any atom or group of atom having negative charge on it.
  12. 12. Molecular Ions: when a molecule loses or gain an electron it form a molecular ion. e.g. hydroinum ion