1 What Is Chemistry


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1 What Is Chemistry

  1. 1. What is Chemistry? Unit 1 – Introduction to Chemistry
  2. 2. What is Chemistry? <ul><li>Chemistry is the study of matter </li></ul><ul><li>What is matter? </li></ul><ul><ul><li>Matter is anything that has mass and volume </li></ul></ul>
  3. 3. What is mass and volume? <ul><li>Mass: </li></ul><ul><ul><li>The amount of matter in an object </li></ul></ul><ul><ul><li>How much an object weighs </li></ul></ul><ul><li>Volume: </li></ul><ul><ul><li>The amount of space an object occupies </li></ul></ul>
  4. 4. Are mass and weight the same thing? Changes with gravity Anywhere Gravity dependent Gravity independent Scale Balance
  5. 5. Now that we know what matter is… <ul><li>Can you think of 5 examples of matter? </li></ul><ul><li>Can you think of the 4 examples of non-matter? </li></ul><ul><li>Brainstorm with your partner please. </li></ul>
  6. 6. Matter – further break down <ul><li>What is the building block of matter? </li></ul><ul><ul><li>Atom – the basic unit of matter </li></ul></ul><ul><li>What is it called when two or more atoms are combined? </li></ul><ul><ul><li>Molecule – two or more atoms that behave as a unit </li></ul></ul><ul><ul><ul><li>They are chemically bonded </li></ul></ul></ul>
  7. 7. Classification of Matter (pg. 3) <ul><li>Matter can be classified into two major groups: </li></ul><ul><ul><li>Pure Substance </li></ul></ul><ul><ul><li>Mixture </li></ul></ul>
  8. 8. Pure Substance <ul><li>Definition: </li></ul><ul><ul><li>Made up of only one kind of atom or molecule </li></ul></ul><ul><ul><li>Example: carbon </li></ul></ul>
  9. 9. Mixture <ul><li>Definition: </li></ul><ul><ul><li>Matter that is made up of more than one kind of atom or molecule. </li></ul></ul><ul><ul><li>Two or more pure substances mixed </li></ul></ul><ul><ul><li>Example: salt water </li></ul></ul><ul><li>Not chemically bonded </li></ul><ul><li>Can be separated by physical means </li></ul>
  10. 10. Further classification: <ul><li>Pure substance and mixture can be further classified </li></ul><ul><ul><li>Pure substance can be further classified into an element or compound </li></ul></ul><ul><ul><li>Mixture can be further classified into a homogeneous or heterogeneous mixture </li></ul></ul>
  11. 11. Element <ul><li>Definition: </li></ul><ul><ul><li>A pure substance that is made of only a single kind of atom </li></ul></ul><ul><ul><li>Cannot be broken down </li></ul></ul><ul><ul><li>Found on periodic table </li></ul></ul><ul><ul><li>Most basic form of matter </li></ul></ul><ul><ul><li>Example: Copper </li></ul></ul>
  12. 12. Compound <ul><li>Definition: </li></ul><ul><ul><li>A pure substance that is made of more than one kind of atom </li></ul></ul><ul><ul><li>2 or more elements chmically bonded </li></ul></ul><ul><ul><li>Example: water </li></ul></ul>
  13. 13. Homogeneous mixture <ul><li>Definition: </li></ul><ul><ul><li>A mixture that has a uniform composition </li></ul></ul><ul><ul><li>Example: Soda </li></ul></ul>
  14. 14. Heterogeneous mixture <ul><li>Definition: </li></ul><ul><ul><li>A mixture that is non-uniform </li></ul></ul><ul><ul><ul><li>It has layers </li></ul></ul></ul><ul><ul><li>Example: muddy water </li></ul></ul>
  15. 15. homework <ul><li>Read 1-1 </li></ul><ul><li>Answer ?s 1-10 on page 23 (write down the question) </li></ul>
  16. 16. States of matter (page 3) <ul><li>Also called the phases of matter </li></ul><ul><li>Solid </li></ul><ul><li>Liquid </li></ul><ul><li>Gas </li></ul>
  17. 17. Solid <ul><li>Has both a definite shape and definite volume </li></ul><ul><li>At the molecular level, the particles that make up the solid are close together and many times are locked into a very regular framework called a crystal lattice </li></ul><ul><ul><li>The atoms and molecules are held tightly in a rigid structure but vibrate slightly about their fixed positions </li></ul></ul><ul><li>Cannot compress </li></ul>
  18. 18. Liquid <ul><li>Definite volume, but variable shape </li></ul><ul><li>Cannot compress </li></ul><ul><li>It conforms to the container in which it is placed </li></ul><ul><li>Particles in the liquid are not held together in a rigid manner that is characteristic of solids </li></ul><ul><ul><li>However, the distances between the particles are constant on average </li></ul></ul><ul><li>Particles are moving much more than in the solid </li></ul><ul><li>There are usually clumps of particles moving relatively freely among other clumps </li></ul>
  19. 19. Gas <ul><li>No fixed shape or volume </li></ul><ul><li>Expand to fill any container they occupy </li></ul><ul><li>The particles move rapidly with respect to each other and act basically independently of each other </li></ul>
  20. 20. Plasma <ul><li>Sea of ions </li></ul><ul><li>Example: Sun </li></ul>
  21. 21. Changing phase <ul><li>Solid </li></ul><ul><li> melting </li></ul><ul><li>freezing Sublimation </li></ul><ul><li>Liquid </li></ul><ul><li>boiling </li></ul><ul><li>condensing </li></ul><ul><li>Gas </li></ul>Deposition
  22. 22. States of matter <ul><li>Identified using the following: </li></ul><ul><ul><li>If an item is a solid, it is followed by (s) </li></ul></ul><ul><ul><ul><li>Ice = H 2 O (s) </li></ul></ul></ul><ul><ul><li>If an item is a liquid, it is followed by (l) </li></ul></ul><ul><ul><ul><li>Tap water = H 2 O (l) </li></ul></ul></ul><ul><ul><li>If an item is a gas, it is followed by (g) </li></ul></ul><ul><ul><ul><li>Steam = H 2 O (g) </li></ul></ul></ul>
  23. 23. Methods of separating mixtures <ul><li>Separate by physical means </li></ul><ul><ul><li>Substances are not altered chemically </li></ul></ul><ul><ul><li>Examples: filtration, evaporation, centrifuge, decant, chromatography, distillation, density </li></ul></ul>
  24. 24. Identification of matter <ul><li>Matter can be identified by two types of properties </li></ul><ul><ul><li>Physical </li></ul></ul><ul><ul><li>Chemical </li></ul></ul>
  25. 25. State Functions <ul><li>Intensive property </li></ul><ul><ul><li>Any property of a system that does not depend on how the process </li></ul></ul><ul><ul><ul><li>Density </li></ul></ul></ul><ul><ul><ul><li>Specific heat </li></ul></ul></ul><ul><li>Extensive Property </li></ul><ul><ul><li>depends on amount of matter </li></ul></ul><ul><ul><ul><li>Volume </li></ul></ul></ul><ul><ul><ul><li>Pressure </li></ul></ul></ul><ul><ul><ul><li>Temperature </li></ul></ul></ul><ul><ul><ul><li>Internal Energy </li></ul></ul></ul>
  26. 26. Physical properties <ul><li>Can be observed without changing the composition of the matter </li></ul><ul><li>Appearance of physical state changes, but not the chemical composition shape </li></ul><ul><ul><li>Examples: color, volume, shape, mass, length, odor, solubility, density, specific heat, melting point and boiling point </li></ul></ul>
  27. 27. Chemical properties <ul><li>Observed only when substances interact with one another </li></ul><ul><li>The original substance changes into something else </li></ul><ul><li>Different chemical substances are formed </li></ul><ul><li>Breaks chemical bonds </li></ul>
  28. 28. Examples of Chemical Properties <ul><li>Rust </li></ul><ul><li>Burning </li></ul><ul><li>Fruit ripening </li></ul><ul><li>Baking </li></ul><ul><li>Souring </li></ul>
  29. 29. Physical vs. Chemical Changes <ul><li>Physical – original substance still exists </li></ul><ul><ul><li>Only the form or physical appearance changes </li></ul></ul><ul><ul><ul><li>Example: </li></ul></ul></ul><ul><ul><ul><ul><li>cutting in half </li></ul></ul></ul></ul><ul><ul><ul><ul><li>writing on paper </li></ul></ul></ul></ul><ul><ul><ul><ul><li>changing the phase of matter </li></ul></ul></ul></ul>
  30. 30. Physical vs. Chemical Changes <ul><li>Chemical - produces one or more new substances </li></ul><ul><ul><li>Observed only when substances interact with one another </li></ul></ul><ul><ul><li>The original substance changes into something else </li></ul></ul><ul><ul><ul><li>Example: </li></ul></ul></ul><ul><ul><ul><ul><li>bubbles (production of a gas) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>change in color </li></ul></ul></ul></ul><ul><ul><ul><ul><li>forms a precipitate (solid) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>produces heat or light (explosions) </li></ul></ul></ul></ul>