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Explaination needed for Stoichiometric problem and is Al salt colorless?

  1. Mar 11, 2009 #1
    1. The problem statement, all variables and given/known data
    The mass of element Q found in 1.00 mole of each of four different compounds is 38.0 grams, 57.0 grams, 76.0 grams, and 114 grams, respectively. A possible atomic weight of Q is

    a) 12.7
    b 19.0
    c 27.5
    d 38.0

    A solution is known to contain an inorganic salt of one of the following

    elements. The solution is colorless. The solution contains a salt of:

    (A) Cu (B) Mn (C) Fe (D) Ni (E) AL

    I do not know the answer to this. I know Cu is blue, Mn is pale pink, Ni is green, Co is redish and Al is silver white.

    2. Relevant equations

    3. The attempt at a solution I know the answer is b. 19.0 grams. However, I'm not 100% sure how to get that answer. I know that it's the only one when the compound masses are divided by it you receive whole numbers. Is that how i was supposed to do the problem? That doesn't make sense to me because other elements could have been in the compound..

    THANK YOU :)
  2. jcsd
  3. Mar 11, 2009 #2


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    Science Advisor
    Homework Helper

    Note that it says the mass of element Q in each sample - not the total mass of the sample!
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