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Alot of help, little time

  1. May 3, 2004 #1
    Hey all, I need alot of help in very little time, as the project is due tomorrow before 3pm. (I know, I should have started it sooner, but I got extremely busy over the week-end and didn't have time)

    anyways, I have 25 questions that need to be answered, and I'll give an answer, and I need to know if its right or wrong and if its wrong, how to correct it.


    first 5 questions,

    1. Area is the number of square units (1 unit)(1 unit) that are contained in the boundaries of a two dimensional figure.
    False. (can't it also be in 3d as well?) Area is whatever is inside of the boundaries of any 2d or 3d object.(?)

    2. The conservation of Mass principle says the mass cannot change in any physical process.
    True. The principle states that mass is neither created nor destroyed, just moved from one form to another. It also states that the mass is constant, but its the amount of energy in any one form may change.

    3. However, if I mix one quart of ice tea wtih one cup sugar, I can observe that I will not end up with one quart + one cup of mixture. I cannot simply sum the two volumes before they were mixed and arrive at the same total volume after they are mixed. This proves that there is not a conservation of volume principle.
    True. (? need help with why its true)

    4. All matter is made up of very tiny peices. These very tiny pieces are particles. These particles are constantly in motion; between the particles there is nothing but empty space. All of the particles, in any particular substance, share exactly the same basic structure that is unique to the particles of that particular substance.
    True. (? need help with why its true)

    5. The density is the main change that affects a substance in a physical process.
    False. Mass is also affected by a physical change and so is volume.
     
  2. jcsd
  3. May 4, 2004 #2

    HallsofIvy

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    Science Advisor

    "1. Area is the number of square units (1 unit)(1 unit) that are contained in the boundaries of a two dimensional figure.
    False. (can't it also be in 3d as well?) Area is whatever is inside of the boundaries of any 2d or 3d object.(?)"

    No, that's completely wrong. In 3d "whatever is inside" is volume, not area. The statement is true.

    "2. The conservation of Mass principle says the mass cannot change in any physical process.
    True. The principle states that mass is neither created nor destroyed, just moved from one form to another. It also states that the mass is constant, but its the amount of energy in any one form may change."

    Assuming you are not talking relativity here, that's correct.

    "3. However, if I mix one quart of ice tea wtih one cup sugar, I can observe that I will not end up with one quart + one cup of mixture. I cannot simply sum the two volumes before they were mixed and arrive at the same total volume after they are mixed. This proves that there is not a conservation of volume principle.
    True. (? need help with why its true)"

    Yes, it's true. As to why- Did you actually do the experiment? Assuming it comes out like this says, then there CAN'T be a "conservation of volume" principle. If an experiment violates some "principle", then that principle is not true!

    "4. All matter is made up of very tiny peices. These very tiny pieces are particles. These particles are constantly in motion; between the particles there is nothing but empty space. All of the particles, in any particular substance, share exactly the same basic structure that is unique to the particles of that particular substance.
    True. (? need help with why its true)"

    This is basically a statement of the "atomic theory". If you want more as to why it is true- well, same as for all physical theories: experimental evidence!

    "5. The density is the main change that affects a substance in a physical process.
    False. Mass is also affected by a physical change and so is volume."

    Your answer doesn't even make sense. The statement says "that AFFECTS a substance". You are saying "is affected BY". You've reversed the meaning of the statement.
     
  4. May 4, 2004 #3
    Thanks for the information. If I actually had the time to do 25 experiments, I would, except I don't. If that comes off as a bit harsh, I'm sorry, but its Finals week and I don't handle tests very well nor final projects like this.
     
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