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2-1 Chemical & Physical Properties

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2-1 Chemical & Physical Properties

  1. 1. Warm-Up <ul><li>What is matter? </li></ul><ul><ul><li>Matter is anything that has mass and takes up space. </li></ul></ul><ul><li>Which of the following sets of measurements are more precise? </li></ul><ul><ul><li>2.74 cm 2.743 cm </li></ul></ul><ul><ul><li>102.3 g 102 g </li></ul></ul><ul><ul><li>0.012 L 0.0002 L </li></ul></ul>
  2. 2. 2-1: Chemical & Physical Properties <ul><li>Distinguish between physical & chemical properties. </li></ul><ul><li>Identify the characteristics of a substance. </li></ul><ul><li>Differenctiate among physical states of matter. </li></ul>
  3. 3. <ul><li>Matter – anything that has a mass and takes up space. </li></ul><ul><li>Law of Conservation of Mass/Matter </li></ul><ul><li>- Matter cannot be created or destroyed in an ordinary chemical reaction just rearranged to form different substances </li></ul><ul><li>Matter can be described using properties . </li></ul>
  5. 5. Characteristics of Matter <ul><li>Physical Properties </li></ul><ul><ul><li>Characteristics of a substance that can be observed without the production of a new substance. </li></ul></ul><ul><li>Examples: </li></ul><ul><ul><li>color </li></ul></ul><ul><ul><li>smell </li></ul></ul><ul><ul><li>taste </li></ul></ul><ul><ul><li>hardness </li></ul></ul><ul><ul><li>density </li></ul></ul><ul><ul><li>texture </li></ul></ul><ul><ul><li>solubility </li></ul></ul><ul><ul><li>melting point </li></ul></ul><ul><ul><li>boiling point </li></ul></ul><ul><ul><li>freezing point </li></ul></ul><ul><ul><li>magnetic attraction </li></ul></ul><ul><ul><li>electrical conductivity </li></ul></ul><ul><ul><li>temperature </li></ul></ul><ul><ul><li>state or phase </li></ul></ul>
  6. 6. Two types of Physical Properties <ul><li>Extensive </li></ul><ul><ul><li>Depends on the particular sample </li></ul></ul><ul><ul><ul><li>for example: volume, mass, weight, shape, etc… </li></ul></ul></ul><ul><li>Intensive </li></ul><ul><ul><li>Depends on the type of matter  NOT how much there is </li></ul></ul><ul><ul><ul><li>For example: color, melting point, specific heat, density, appearance, etc… </li></ul></ul></ul>
  7. 7. <ul><li>Chemical Properties </li></ul><ul><ul><li>describes how a substance reacts or fails to react with other substances to produce new substances. </li></ul></ul><ul><li>Examples: </li></ul><ul><ul><li>Oxidation </li></ul></ul><ul><ul><li>Corrosion </li></ul></ul><ul><ul><li>Hydrolysis </li></ul></ul><ul><ul><li>Combustion </li></ul></ul><ul><ul><li>Flammability </li></ul></ul><ul><ul><li>Reaction to Acid or Base. </li></ul></ul>
  8. 8. Two Types of Changes <ul><li>Physical Change </li></ul><ul><ul><li>an alteration of a substance that only changes the physical properties of the substance. </li></ul></ul><ul><li>* Does not change the chemical composition of the matter!! </li></ul>
  9. 10. <ul><li>Chemical Change </li></ul><ul><li>a change of the chemical composition of a substance that results in the formation of a new substance </li></ul><ul><ul><li>ALWAYS forms a new substance that has different physical and chemical properties than the original substance. </li></ul></ul><ul><li>*Also known as a chemical reaction. </li></ul>
  10. 14. Recognizing Chemical Change <ul><li>Change in Color </li></ul><ul><ul><li>Copper turns green. </li></ul></ul><ul><li>Production of Gas </li></ul><ul><ul><li>Baking soda in vinegar produce CO 2 . </li></ul></ul><ul><li>Formation of Precipitate </li></ul><ul><ul><li>Any formation of a solid that separates from liquid. </li></ul></ul><ul><li>Energy release </li></ul><ul><ul><li>Heat or light given off. </li></ul></ul>
  11. 15. When a physical change in a sample occurs, which of the following does NOT change? <ul><li>shape </li></ul><ul><li>volume </li></ul><ul><li>mass </li></ul><ul><li>composition </li></ul>
  12. 16. One example of a physical change is <ul><li>burning paper. </li></ul><ul><li>baking cookies. </li></ul><ul><li>the rusting of iron. </li></ul><ul><li>mixing a milkshake. </li></ul>
  13. 17. Kinetic Theory of Matter <ul><li>All matter is made of tiny particles in constant motion. </li></ul><ul><li>Potential Energy (PE) </li></ul><ul><ul><li>energy due to the position or condition </li></ul></ul><ul><ul><li>at the atomic level: the distance between the particles </li></ul></ul><ul><li> closer= lower PE  farther = higher PE </li></ul><ul><li>Kinetic Energy (KE) </li></ul><ul><ul><li>energy due to motion </li></ul></ul><ul><li> Faster= higher KE  Slower= lower KE </li></ul>
  14. 18. Arranged in orderly pattern Yes Yes Touching, but not tightly packed Yes No Far apart and rarely touching No No State or Phase Particle level picture Particles description Keep Volume? Keep shape? Solid Liquid Gas
  15. 19. Very Low Ice Low Water High Vapor Vibrational only Vibrational & translational Move freely Low Medium High State or Phase Particle Movement Amount PE Amount KE Example Solid Liquid Gas
  16. 20. <ul><li>Plasma </li></ul><ul><ul><li>extraordinary state of matter </li></ul></ul><ul><ul><li>consists of high energy particles </li></ul></ul><ul><ul><li>electrons are stripped from their nuclei </li></ul></ul><ul><li>examples : </li></ul><ul><ul><li>fluorescent lights </li></ul></ul><ul><ul><li>stars </li></ul></ul><ul><ul><li>lightning </li></ul></ul><ul><li>*Most Abundant State of Matter in the Universe!* </li></ul>
  17. 21. An object that has kinetic energy must be <ul><li>moving. </li></ul><ul><li>falling. </li></ul><ul><li>elevated. </li></ul><ul><li>at rest. </li></ul>
  18. 22. Characteristics of matter that describe how a substance reacts or doesn’t react to other substances is called <ul><li>physical property </li></ul><ul><li>chemical property </li></ul><ul><li>intensive property </li></ul><ul><li>extensive property </li></ul>
  19. 23. Phase Changes – Changes of State <ul><li>Adding or removing energy (heat) to a substance causes phase changes </li></ul><ul><li>The particles potential energy is increased or decreased. </li></ul><ul><li>During a phase change, temperature does NOT change </li></ul>
  20. 24. Phase changes <ul><li>Melting S Δ L (adding energy) </li></ul><ul><li>Freezing L Δ S (removing energy) </li></ul><ul><li>*Melting point & freezing point of a substance occur at the same temperature. </li></ul>
  21. 25. Phase changes <ul><li>Boiling L Δ G (adding energy) </li></ul><ul><li>Condensation G Δ L (removing energy) </li></ul><ul><li>Evaporation L Δ G (adding energy) </li></ul><ul><li>*Difference between boiling & evaporation: </li></ul><ul><ul><li>Boiling  a specific temp. below the surface </li></ul></ul><ul><ul><li>Evaporation  any temp. at the surface </li></ul></ul>
  22. 26. Phase changes <ul><li>Deposition G Δ S (removing energy) </li></ul><ul><li>-Examples: </li></ul><ul><li>snow </li></ul><ul><li> frost </li></ul><ul><li>Sublimation S Δ G (adding energy) </li></ul><ul><li>-Examples: </li></ul><ul><li>solid CO 2 (dry ice) </li></ul><ul><li>solid air fresheners </li></ul>