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9 the particle theory-1


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9 the particle theory-1

  1. 1. The Particle Theory Chapter 2
  2. 2. The Particle TheoryMore than 2000 years ago, a Greek philosopher Democritus suggested that matter was made of tiny particles too small to be seen.He thought if you kept cutting a substance into smaller and smaller pieces, you would find the building blocks of matter.
  3. 3. 4 Principles of the Particle Theory1. All matter is made of tiny particles.2. All particles of one substance are the same. - Different substances are made of different particles.3. The particles are always moving. - The more energy the particles have, the faster they move.4. There are attractive forces between particles. - These forces are stronger when the particles are closer together.
  4. 4.  Theparticle theory helps to explain two categories of substances that are encountered in chemistry.
  5. 5. Two Categories of SubstancesCategory 1: Pure Substances - contains only one kind of particle - Types: elements and compoundsCategory 2: Mixtures - contains two or more different pure substances - Types: homogeneous and heterogeneous mixtures
  6. 6. Category 1: Pure SubstancesType 1: Elements – pure substances that cannot be broken down into simpler substances - Examples: think Periodic table (oxygen, hydrogen)Type 2: Compounds – pure substances that contain two or more elements - Examples: Water (H2O), sugar (C6H12O6)
  7. 7. Category 2: MixturesType 1: Homogeneous (also known as solutions) – may be made up of solids, liquids or gases - this mixture is uniform (the same) throughout - Examples: air, alloys, kool aid, white vinegar, orange juice without the pulpType 2: Heterogeneous – see each part easily, separated physically - this mixture is not uniform throughout - Examples: pizza, garbage, beach sand, vegetable soup
  8. 8. How to Classify Mixtures When two pure substances are mixed together, they may mix smoothly or unevenly. If the substances mix well with one another, the mixture is called a solution. If the particles don’t mix well together then we have a heterogeneous mixture.
  9. 9. Classify the Following Salt and water  solution Pizza  heterogeneous mixture Garbage  heterogeneous mixture Air  solution
  10. 10. Atoms and Molecules Atoms - each atom is made of one type of element - scientists now call the particles in the particle theory atoms - the periodic table of elements has 118 elements Molecules - contains two or more atoms joined together in combinations - Ex. C4H8 – contains 4 carbon atoms and 8 hydrogen atoms
  11. 11. Guess the Molecule I have 2 hydrogen atoms  I have 1 oxygen atom  I am water
  12. 12. Guess the Molecule  I have 10 hydrogen atoms  I have 2 oxygen atoms  I have 7 carbon atoms  I have 4 nitrogen atoms  I am desired in the morning but avoid me in the evening  Cola drinks have contain me  I am what makes coffee special  I am caffeine
  13. 13. Guess the Molecule  I have 6 hydrogen atoms  I have 6 oxygen atoms  I have 6 carbon atoms  Everybody needs me  I will help keep colds away  You can get me by eating oranges  I am vitamin C
  14. 14. Guess the Molecule  I have 8 hydrogen atoms  I have 4 oxygen atoms  I have 9 carbon atoms  I am used quite often by teachers, usually in pairs  I am white in color  You need water when you use me  I will make you feel better  I am aspirin