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EELO AMERICAN UNIVERSITY BORAMA, AWDAL SOMALILAND

Md. Faysal Ahamed Khan Welcome to the class of Chemistry I Course No. CHEM 211 Credit hours 3. EELO AMERICAN UNIVERSITY BORAMA, AWDAL SOMALILAND. 1. To better understand the world: what it is made of and how it works.

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EELO AMERICAN UNIVERSITY BORAMA, AWDAL SOMALILAND

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  1. Md. Faysal Ahamed Khan Welcome to the class of Chemistry I Course No. CHEM 211 Credit hours 3 EELO AMERICAN UNIVERSITYBORAMA, AWDALSOMALILAND

  2. 1. To better understand the world: what it is made of and how it works. 2. Because it is the most practical and relevant of the sciences - chemistry is the study of EVERYTHING! 3. It is the “Central Science” - All other sciences intersect at and depend on chemistry. 4. It is essential to the national and local economies. Why Study Chemistry?

  3. 5. It is required for virtually every major involving science or engineering. 6. An awareness of the principles of chemistry is essential to being an informed and responsible citizen in a highly technical society. 7. It is incredibly fascinating and a lot of fun! Why Study Chemistry?

  4. What is chemistry? Chemistry is the study of the properties, composition, and structure of matter, the physical and chemical changes it undergoes, and the energyassociated (liberated or Absorbed) during those changes.

  5. Matter: Anything that has mass and occupies space Ex: oxygen, air, chair, water, rocks, gasoline

  6. Matter • Atoms are the building blocks of matter. • Each element is made of the same kind of atom. • A compound is made of two or more different kinds of elements.

  7. Properties of Matter • Physical: properties that can be measured without changing the chemical composition of the substance – E.g. melting point, density. • Chemical: properties that described a substance’s reactivity. E.g. rusting is a chemical property of Iron,

  8. EOS

  9. Physical Changes • A physical change is one that does not occurs any change in chemical composition Water freezing to form ice Iron melting in a blast furnace

  10. Chemical Changes • A chemical change involves a change in chemical composition Iron Rusting Natural gas burning

  11. Quick review Problem 1: What is a physical change? List the physical changes that occur when one makes cheese. Ans: Physical changes include:1. Dissolving of salt in water 2. Evaporation of water from solution 3. Stirring to mix Problem 2: What is a chemical change? List the chemical changes that occur when one makes cheese. Ans: changes include:1. bacteria convert the sugar in milk (lactose) to lactic acid 2. special bacteria ferment the remaining lactose and produce carbon dioxide bubbles in the cheese.

  12. Classification of Matter

  13. Air Gold Salad Salt sugar in water Water Different kinds of matter...

  14. Matter yes No Can it be separated by any physical process? Pure substances Mixtures Can it be decomposed chemically? Is the composition uniform? yes yes No No Heterogeneous mixture Homogeneous mixture (Solution) Compounds Elements

  15. Classification of Matter Matter Substances Mixtures Homogeneous (Solutions) Elements Compounds Heterogeneous

  16. Air Salad sugar in water Based on the previous classification scheme, can you classify the kinds of matter illustrated? • Which can be separated? • So, these are Mixtures! • But which type of mixtures? • Homogeneous or heterogeneous?

  17. Air Salad sugar in water Uniform Not uniform Homogenous Mixtures Heterogeneous Mixtures

  18. Gold Salt Water Now... Those that can’t be separated are Pure Substances Bur are they Compounds or Elements?

  19. Gold Salt Water Which can be decomposed by chemical means, like heating, electricity...and which cannot? Compounds Elements

  20. Summary... • Matter can be classified into: Mixtures and pure substances. • Mixtures can be homogenous or heterogeneous. • Homogeneous mixtures: Uniform • Heterogeneous mixtures: Not Uniform • Pure substances can be elements or compounds. • Elements can’t be decomposed. • Compounds can be decomposed by chemical means.

  21. States of matter Water as example LIQUID GAS SOLID

  22. State of matter • Commonly, a given kind of matter exists in different physical forms under different conditions. For example: water exists as ice (solid), as liquid water and as steam (gaseous water). • Solid: the form of matter characterized by rigidity; a solid is relatively incompressible and has fixed shape and volume. • Liquid: the form of matter that is a relatively incompressible fluid; a liquid has a fixed volume but no fixed shape. • Gas: the form of matter that is an easily compressible fluid; a given quantity of gas will fit into a container of any size and shape. The three form of matter-solid, liquid, and gar-are referred to as the state of matter.

  23. States of Matter

  24. Note that the first letter is always capitalized and the second is lowercase EOS Chemical Symbols A one- or two-lettered designation derived from the name of the element Most symbols are based on English names: Hydrogen = H Neon = Ne Chromium = Cr

  25. Chemical Symbols In some cases, symbols come from Latin names

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