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Homework Help: Physical and Chemical Changes

  1. Mar 17, 2007 #1
    This question asks me to classify each of the following as a physical or a chemical change.

    a. Tarnishing of copper
    b. Heating sugar to form caramel
    c. Pouring concentrated nitric acid on a copper coin to form brown fumes
    d. Evaporating a solution of copper sulfate to dryness (to form blue crystals)
    e. Heating lead nitrate until brown fumes form
    f. Adding sodium carbonate to water
    g. Adding sodium metal to water

    To me they all seem like chemical changes. :confused: The only ones that might not be are d and g, but I'm not really sure.
     
  2. jcsd
  3. Mar 18, 2007 #2
    Hey Zappa;

    Go to your favorite search engine, type in "Sodium", choose a site, and see what it says about when Sodium is added to water. Good luck.

    Best of health.

    Steve
     
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