Physical Chemical Changes Is melted butter still butter
Physical & Chemical Changes • Is melted butter still butter? • Is soured milk still milk? • Are the ashes from a fire made of the same “stuff” as wood? 7 th Grade Brandy Butcher
What is a physical change? �Change that affects one or more physical properties of a substance �A new substance is not formed �The substance keeps its identity (name)
Examples of Physical Change �Any state change ◦ Melting ◦ Freezing ◦ Evaporating �Dissolving �Cutting �Bending
Examples of Physical Changes in Nature �Water Cycle �Erosion
Can you think of any examples?
What is a chemical change? �One or more substances are changed into a new substance �New and different properties �New identity (name)
Examples of a Chemical Change �Cooking �Burning �Rusting
Examples of Chemical Changes in Nature �Carbon Cycle �Nitrogen Cycle �Chemical Weathering
Can you think of any examples?
What are the signs a chemical change is happening? �Change in color �Change in odor �Production of heat �Production of fizzing, foam, bubbles �Production of sound �Production of light
What signs do this changes demonstrate? Change in odor and color at e H nd/ u o S t/ Ligh Change in odor and color Sou / t h Lig eat H / nd Change in color
Physical or Chemical Change? Frying an egg? Rusting of Iron Shredding Paper Melting of ice cream
Incorrect. Try again!
Correct! Try the next one!
Physical or Chemical Change? �Souring �Physical Milk? or Chemical
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Correct! Try the next one!
Physical or Chemical Change? �Shredding �Physical paper? or Chemical
Incorrect. Try again!
Correct!
Law of conservation of mass �During a chemical change, matter is neither created nor destroyed. It undergoes physical and chemical changes. This is known as the law of conservation of mass. �Mass of reactants=Mass of products. http: //www. youtube. com/watch? v=xql 1 Tb 9 k. Eik http: //www. youtube. com/watch? v=ww. JJK 4 kor. Rg
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