Tuesday, July 5, 2011

Homework #1 week one semester two


  1. Classify each of the following as a chemical or a physical property
    1. Copper has a reddish brown color- physical property
    2. Propane burns readily- chemical property
    3. CO2 gas extinguishes a candle flame-chemical property
    4. Honey pours slowly- physical property
  2. Classify each of the following as a chemical or a physical property:
    1. Metal wire can be bent- physical property
    2. Ice floats in water- physical property
    3. Paper is flammable- chemical property
    4. Sugar is soluble in water- chemical property
  3. Classify each of the following as a chemical or a physical change
    1. A candle burns- chemical change
    2. An opened carbonated beverage fizzes- chemical change
    3. Hair curls as result of a “perm”- chemical change
    4. As shoes wear out, holes appear in the soles- Physical change
  4. Classify each of the following as a chemical or a physical change
    1. A cut apple left out in the air turns brown because when the apple is cut it begins reacting with the air causing a color change (somewhat like what happens to copper)
    2. Flashlight batteries lose their “charge” after extended use are examples of a physical change because they lose their electrical conductivity which is a physical trait, yet their shapes and observable features are still the same.
    3. Dry cleaning removes oils from clothing and is a physical change because the clothes are still the same material just with the oil removed almost like a suspension.
    4. Italian salad dressing separates is a physical change because both substances in the dressing that separated from each other are still in their original states.
  5.  Combine flour, baking soda and salt in small bowl. Beat butter, granulated sugar, brown sugar and vanilla extract in large mixer bowl until creamy. Add eggs, one at a time, beating well after each addition. Gradually beat in flour mixture. Stir in morsels and nuts. Drop by rounded tablespoon onto ungreased baking sheets.
  6. When you combine the dry ingredients such as flour, baking soda and salt, it is a physical change because, though they are combined together, they are separate materials. However, when the butter, sugar, brown sugar, and vanilla extract are added together it is an example of a chemical change because as they mix they change shape and become of homogenous mixture and almost impossible to separate. Once the eggs are added they represent a chemical change as well for the reasons listed above and when all the ingredients are mixed together it connotes a chemical change because they change in substance. When the ingredients bake and rise they change chemically becoming cookies.
  7. Classify each property as a characteristic of metals or nonmetals:
    1. Shiny in appearance- metals
    2. Does not react with acids- Non metals
    3. Shatter easily- Non metals
    4. Electrically conductive- Metals
  8. Classify each of these elements as a metal, a nonmetal, or a metalloid:
    1. Tungsten- Metal
    2. Antimony- Metalloid
    3. Krypton- Nonmetal
    4. Sodium- Metal
  9. Two elements that are metalloids are:
    1. Antimony- Sb
    2. Germanium- Ge
  10. What I would expect to happen if I tapped the following elements with a hammer:
    1. Iodine- Nothing the hammer would go through because iodine is a liquid
    2. Zirconium- Bend to the hammer because it is a metal
    3. Phosphorous- It is a nonmetal and should have no reaction to the hammer
    4. Nickel- Bend to the hammer
  11. Two properties that make nonmetals unsuitable for electric wiring are:
    1. They are not conductive
    2. Brittle so an electrical current cannot pass
  12. Three properties that make metals suitable for use in coins:
    1. Durability- they can last through harsh changes in the weather for example.
    2. Luster- the shiny appearance makes them more interesting and desired
    3. Wont corrode- Stays in shape for long periods of time and does not disintegrate. 

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