Notes Science Tennessee SPI Objective: Physical or Chemical Changes Notes Science Tennessee SPI Objective: Interpret the results of an investigation to determine whether a physical or chemical change has occurred. Essential Questions 1) How do I recognize a physical change? 2) How do I recognize a chemical change? “I Can” Statement I can contrast physical and chemical changes. Success Criteria I can prove that I understand this topic by explaining the differences between a physical and chemical change and when I can give an example of each.

Physical or Chemical Changes SPI 0807.9.8 Physical or Chemical Changes Notes Science Physical Changes A change of matter from one form to another without a change in chemical properties. Changes the appearance of an object, but does not change the composition of the object. In other words, the way it looks is changed, but what it is does not change. (like dressing up for a costume party) Physical changes do not form new substances. Can be fairly easily undone or reversed

H2O H2O H2O Notes Science Physical Change: SPI 0807.9.8 Physical or Chemical Changes Notes Science Physical Change: It looks different, but is still the same material. No chemical reaction has occurred. Example: Changes of state ARE NOT chemical reactions In other words, liquid to solid to gas are only physical changes Liquid Water Solid Water Water Vapor H2O H2O H2O

Physical or Chemical Changes No Chemical Change Occurs! SPI 0807.9.8 Physical or Chemical Changes Notes Science Examples of Physical Change Melting Freezing Boiling Bending Cutting Crushing Tearing Breaking Smashing Dissolving In every example here, the appearance is changed, but the composition remains the same. No Chemical Change Occurs!

Physical Change Examples Melting For each of these examples, the appearance is changed, but the composition remains the same. Freezing Boiling No Chemical Change!

Physical Change Examples Cutting For each of these examples, the appearance is changed, but the composition remains the same. Crushing No Chemical Change! Tearing

Physical Change Examples Breaking For each of these examples, the appearance is changed, but the composition remains the same. Smashing No Chemical Change! Dissolving

5 Key Points About Chemical Reactions Chemical Change Is the result of a chemical reaction A new substance is formed Cannot be easily undone or reversed 5 Key Points About Chemical Reactions 1) A new substance is formed by rearranging the atoms 2) The properties of the new substance are different from the substances that you started with 3) No atoms are created or destroyed in chem reactions 4) Atomic bonds are broken and new bonds are formed (at the valence electron level) 5) compounds come from chemical reactions

Chemical Change Example Iron and oxygen react to form a compound called iron oxide. Color Change: From silvery-gray to red-orange-brown Commonly Called Rust 1966 VW Beetle Bare Metal-No Paint 1966 VW Beetle Rusting away Chemical Equation 2Fe + 3O2 2FeO3

Chemical Change Example Copper + oxygen react to form a compound called copper oxide. Color Change: From golden-brown to aqua-marine green Also Called Rust Statue of Liberty Original look-1886 Statue of Liberty Modern look-2014 Chemical Equation 4Cu + O2 2Cu2O

Chemical Change Example The Space Shuttle used solid rocket propellant called APCP Burning APCP results in a very powerful chemical reaction Space Shuttle (USA) Lift Off Chemical Equation 10Al + 6NH4ClO4 4Al2O3 + 2AlCl3 + 12H2O + 3N2

Chemical Change Example Upset stomach? You can take Alka Seltzer effervescent tablets Drop the tablets in water and you get a chemical reaction Chemical Equation 3NaHCO3 + C6H8O7 Na3C6H5O7 + 3CO2 + 3H2O

Chemical Change Example Soured milk is the result of a chemical reaction Bacteria converts lactose to lactic acid Chemical Equation C12H22O11 + H2O 4C3H6O3

Physical or Chemical Changes SPI 0807.9.8 Physical or Chemical Changes Science Questions Sample Question Here is an example of a question you might see on a quiz or test.

Physical or Chemical Changes SPI 0807.9.8 Physical or Chemical Changes Science Questions Sample Question …a question you might see on a quiz or test.

Physical or Chemical Changes SPI 0807.9.8 Physical or Chemical Changes Science Questions Sample Question Here is an example of a question you might see on a quiz or test.

Physical or Chemical Changes SPI 0807.9.8 Physical or Chemical Changes Science Questions Sample Question …a question you might see on a quiz or test.

Physical or Chemical Changes SPI 0807.9.8 Physical or Chemical Changes Science Questions Sample Question …a question you might see on a quiz or test.