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Law of Multiple Proportions

  1. Sep 20, 2005 #1
    If X and Y represent atoms of different elements, as described in I, which descriptions II - IV represent the law of multiple proportions?

    I: 4 X atoms and 12 Y atoms are spotted

    II: 4 molecules; each are comprised of 1 X atom and 3 Y atoms
    III: 4 molecules; each are comprised of 1 X atom and 2 Y atoms
    IV: 2 sets of diatomic molecules are spotted; 2 diatomic molecules of X and 6 diatomic molecules of Y

    a. only descriptions II and IV
    b. descriptions II, III, IV
    c. only descriptions III and IV
    d. only descriptions II and III

    Is the correct choice d. II and III? (Am I supposed to look at the numbers of element to determine if the mass ratios are whole numbers of each other?)

  2. jcsd
  3. Sep 21, 2005 #2


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    first, state the law of multiple proportions
  4. Sep 21, 2005 #3
    "If two elements form more than one compound between them, then the the ratios of the weights of the second element which combine with a fixed mass of the first element will be ratios of small whole numbers."
  5. Sep 21, 2005 #4


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    This is a terribly composed question, but I think you have the correct answer. If you first observe X:Y = 1:2 and then observe X:Y = 1:3, that gives you Y/X(1st obs):Y/X(2nd obs) = 2:3, a simple whole number ratio.
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