Lecture 1&2
Download as PPT, PDF0 likes299 views
1. Chemistry is the study of matter and its properties, composition, structure and the changes it undergoes. 2. Matter exists in three physical forms - solid, liquid and gas - depending on conditions like temperature and pressure. 3. Elements and compounds are the two main categories of pure substances, while mixtures can be either homogeneous or heterogeneous.
Lecture 1&2
- 1. Md. Faysal Ahamed Khan Welcome to the class of Chemistry I Course No. CHEM 211 Credit hours 3
- 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.
- 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!
- 4. Chemistry is the study of the properties, composition , and structure of matter , the physical and chemical changes it undergoes, and the energy associated (liberated or Absorbed) during those changes.
- 5. Anything that has mass and occupies space Ex: oxygen, air, chair, water, rocks, gasoline
- 6. 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. 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. 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. A chemical change involves a change in chemical composition Iron Rusting Natural gas burning
- 11. 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.
- 13. Air sugar in water Water Salt Gold Salad
- 14. Can it be separated by any physical process? Is the composition uniform? Can it be decomposed chemically? Matter Mixtures Pure substances yes No yes No yes No Homogeneous mixture (Solution) Heterogeneous mixture Compounds Elements
- 15. Matter Substances Mixtures Elements Compounds Homogeneous (Solutions) Heterogeneous
- 16. 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 ? Air sugar in water Salad
- 17. Uniform Not uniform Homogenous Mixtures Heterogeneous Mixtures Air sugar in water Salad
- 18. Now... Those that can’t be separated are Pure Substances Bur are they Compounds or Elements ? Water Salt Gold
- 19. Which can be decomposed by chemical means, like heating, electricity...and which cannot? Compounds Elements Water Salt Gold
- 20. 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. GAS LIQUID SOLID Water as example
- 22. 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 Shape Volume Gas indefinite indefinite Liquid indefinite definite Solid definite definite
- 24. 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 EOS Note that the first letter is always capitalized and the second is lowercase
- 25. In some cases, symbols come from Latin names
Editor's Notes
- #2: This is the out look of my presentation. Start of the lecture: Good Morning students. This is …….from Bangladesh. I will be teaching Chemistry I to you for this semester. Why do you think you have to study Chemistry? ………………………………………………………………………………………………………………………………………………………… .. Now, What is Chemistry?