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Physical Properties Quiz

Physical Properties Quiz. List three physical properties of water. Why does a golf ball feel heavier than a table-tennis ball? Which of the following statements about density is true? a. Density depends on mass and volume. b. Density is weight per unit volume.

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Physical Properties Quiz

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  1. Physical Properties Quiz • List three physical properties of water. • Why does a golf ball feel heavier than a table-tennis ball? • Which of the following statements about density is true? a. Density depends on mass and volume. b. Density is weight per unit volume. c. Density is measured in milliliters. d. Density is a chemical property.

  2. Chemical Properties • Chemical Properties describe a substance based on its ability to change into a new substance with different properties. • For example a piece of wood can be burned to create a new substance (ash and smoke) • Think of our CSI unit. When we burned the wool and cotton we were investigating their chemical properties.

  3. Observing Chemical Properties • Not as easy to observe as physical properties. • You can only observe the flammability of wood while the wood is burning. • A substance always has its chemical properties. • A piece of wood is flammable even when it is not burning!

  4. Car Properties • Chemical Properties of Iron: • Non-reactive with oil and gasoline • Reactive oxygen which can cause cars to rust! • Physical Properties of Iron • Strength • Malleability • High melting point

  5. Physical vs. Chemical Properties • You can observe physical properties without changing the identity of the substance. • You can observe chemical properties only in situations in which the identity of the substance could change.

  6. Physical Changes • A physical change is one that affects one or more physical properties of a substance. • For example if you took a piece of chalk and broke it into pieces you have changed the physical property of the size of the chalk. • However the chemical properties of the chalk still remain the same. • Chalk will still produce bubbles if placed in vinegar.

  7. Examples of Physical Change • Melting (for example butter), turns from a solid to a liquid, but the identity of the butter did not change • Freezing water for ice cubes • Sanding a piece of wood • Cutting your hair • Crushing an aluminum can • Bending a paper clip • Mixing oil and vinegar

  8. Can Physical Changes be undone? • They do not change the identity of substances, and are therefore usually easy to undo. • For example: leaving butter on the counter where it melts. Later if you put the butter into the refrigerator it will reverse the change.

  9. Chemical Changes • Chemical changes form NEW substances! • Chemical change occurs when one or more substances are changed into entirely new substances with different properties. • A chemical property describes a substance’s ability to go through a chemical change. • A chemical change is the actual process in which that substance changes into another substance.

  10. Examples of Chemical Change • Sour milk smells bad because bacteria have formed new substances in the milk. • Statue of Liberty: should be shiny orange-brown copper, but the metals interaction with carbon dioxide and water has formed a new substance: copper carbonate!

  11. Clues to Chemical Change • Chemical changes often cause color changes, fizzing or foaming heat, or the production of sound, light, or odor. • Can chemical changes be undone?

  12. Answer: No, you cannot reverse chemical changes using physical means. • For example: you cannot un-crumple or iron out a chemical change. • Imagine trying to un-bake a cake? • Chemical changes are difficult to reverse, however under the right conditions by other chemical changes sometimes they can be reversed.

  13. Think about it… • A hot gas formed when hydrogen and oxygen join to make water helps to blast this space shuttle into orbit. • The water formed can be split back into hydrogen and oxygen by using an electric current. • A lot of work, but the chemical change can be undone.

  14. Quiz #3 • Classify each of the following properties as either physical or chemical: • Reacts with water • Dissolves in acetone • Is blue • Does not react with hydrogen • List 3 clues that indicate a chemical change might be taking place.

  15. http://www.youtube.com/watch?v=qqqmFFCwd7k • http://www.youtube.com/watch?v=pmHxYE_vDBs • http://www.youtube.com/watch?v=xYFAj50c7xM

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