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Homework Help: Atoms and molecules

  1. Jan 17, 2010 #1
    1. The problem statement, all variables and given/known data
    A cubic centimeter of water has a mass of 1.00g. How many molecules does it contain?
    How many atoms are in 1.00g ice cube?


    2. Relevant equations
    1 mole=6.02 x 10^23 molecules(or atoms)
    1 mole of H20= 18g

    3. The attempt at a solution
    The answers are: 3.3 x10^22 molecules.( I got this answer)
    1 x 10^23 atoms( I didn't get this answer)

    Please help! Thanks!
     
  2. jcsd
  3. Jan 17, 2010 #2

    ideasrule

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    So if 18 g of water has 6.02*10^23 molecules, how many does 1 g have?
     
  4. Jan 17, 2010 #3
    1g has 3.3 x 10^22 molecules..
    how do i find the atoms?
     
  5. Jan 17, 2010 #4

    ideasrule

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    Water is H2O, two hydrogen atoms and one oxygen atom
     
  6. Jan 17, 2010 #5

    ideasrule

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    BTW, did you get 2400 on the SAT? If so, congrats!
     
  7. Jan 17, 2010 #6
    no...that's the dream score..lol

    Ok..how do you get 1x 10^23 atoms?? for the second question?
    i got the answer for the 1st question..
     
  8. Jan 17, 2010 #7

    ideasrule

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    You don't. 1*10^23 is the wrong answer. Somebody screwed up and divided by 3 instead of multiplying by 3.
     
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