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Homework Help: A couple of chem problems

  1. Oct 7, 2003 #1
    Consider this eq, It is balanced:
    KCN+HCl=KCl+HCN

    If a sample of 0.140g of KCN is treated with an excess of HCl, calculate the amount of HCN formed, in grams:

    I just want to know if I did this right

    0.140g KCN/65g KCN = x/27g HCN
    and I got .058 g


    Another probem:
    Ammonium Nitrate decomposes to form n2o and h20, write a balanced eq. How many grams of n20 are formed if 0.46moles of Ammonium Nitrate is used in the reaction.

    I did:
    36.8 g NH4NO3/ 80g NH4NO3= x/44g N2O

    I went ahead and converted mol to g in the beginning.

    I got 20.24g N2O


    One more question, :Calculate the number of moles of H3PO4 that will react with 5.55 mol of Ba(OH)2 to form Ba(H2PO4)2 and water

    Now, I set up a mole ratios right?
     
  2. jcsd
  3. Oct 7, 2003 #2
    One more question:

    2Al+3FeO=3Fe+Al2O3

    When I am doing Mass to Mass ratio, I would do #g Al/ molecular weight Al x 2

    for example if I am reacting 468g Al, I put it over 54g Al, not just 27.

    I hope that makes sense.
     
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