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Changes of matter

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Changes of matter

  1. 1. Changes in Matter
  2. 2. PHYSICAL CHANGES
  3. 3. _______ ______ <ul><li>occurs when the substance changes state but does not change its chemical composition. </li></ul><ul><li>For example: water freezing into ice, cutting a piece of wood into smaller pieces, etc. </li></ul><ul><li>The form or appearance has changed, but the properties of that substance are the same </li></ul><ul><li>(i.e. it has the same melting point, boiling point, chemical composition, etc.) </li></ul>
  4. 4. <ul><li>Melting point </li></ul><ul><li>Boiling point </li></ul><ul><li>Vapor pressure </li></ul><ul><li>Color </li></ul><ul><li>State of matter </li></ul><ul><li>Density </li></ul><ul><li>Electrical conductivity </li></ul><ul><li>Solubility </li></ul><ul><li>Adsorption to a surface </li></ul><ul><li>Hardness </li></ul>_______ _________
  5. 5. Physical Changes <ul><li>When you step on a can and crush it, you have forced a physical change. The shape of the object has changed. It wasn't a change in the state of matter, but something changed. </li></ul>
  6. 6.
  7. 7. CHEMICAL CHANGES
  8. 8. Chemical Changes <ul><li>A chemical change involves one or more substances changing into a new substance . </li></ul><ul><li>When iron (Fe) rusts you can see it happen. </li></ul><ul><li>The actual molecules have changed their structure (the iron oxidized). </li></ul>
  9. 9. What are chemical changes? <ul><li>occurs when a substance changes into something new. </li></ul><ul><li>This occurs due to heating, chemical reaction, etc. </li></ul><ul><li>You can tell a chemical change has occurred if the density, melting point or freezing point of the original substance changes. </li></ul><ul><li>Many common signs of a chemical change can be seen (bubbles forming, mass changed, etc). </li></ul>
  10. 10. <ul><li>Reaction with acids </li></ul><ul><li>Reaction with bases (alkalis) </li></ul><ul><li>Reaction with oxygen (combustion) </li></ul><ul><li>Reaction with other elements </li></ul><ul><li>Decomposition into simpler substances </li></ul><ul><li>Corrosion </li></ul>_______ _________
  11. 11. Chemical Changes <ul><li>The ability of a substance to undergo a specific chemical change is called a chemical property . </li></ul><ul><ul><li>iron plus oxygen forms rust, so the ability to rust is a chemical property of iron </li></ul></ul><ul><li>During a chemical change (also called chemical reaction), the composition of matter always changes. </li></ul>
  12. 12. Chemical Reactions are… <ul><li>When one or more substances are changed into new substances. </li></ul><ul><li>Reactants - the stuff you start with </li></ul><ul><li>Products - what you make </li></ul><ul><li>The products will have NEW PROPERTIES different from the reactants you started with </li></ul><ul><li>Arrow points from the reactants to the new products </li></ul>
  13. 13. Recognizing Chemical Changes <ul><li>Energy is absorbed or released (temperature changes hotter or colder) </li></ul><ul><li>Gas production (bubbling, fizzing, or odor change; smoke) </li></ul><ul><li>formation of a precipitate - a solid that separates from solution (won’t dissolve) </li></ul><ul><li>Irreversibility - not easily reversed </li></ul><ul><li>But, there are examples of these that are not chemical – boiling water bubbles, etc. </li></ul>
  14. 14. Physical vs. Chemical Change <ul><li>Physical change will change the visible appearance, without changing the composition of the material. </li></ul><ul><ul><li>Boil, melt, cut, bend, split, crack </li></ul></ul><ul><ul><li>Is boiled water still water? </li></ul></ul><ul><li>Can be reversible, or irreversible </li></ul><ul><li>Chemical change - a change where a new form of matter is formed. </li></ul><ul><ul><li>Rust, burn, decompose, ferment </li></ul></ul>
  15. 15. Chemical changes in matter <ul><li>New Matter is formed. </li></ul><ul><ul><li>Burning </li></ul></ul><ul><ul><li>Rusting </li></ul></ul><ul><ul><li>Cooking </li></ul></ul>

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