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Some chemistry problems I don't know where to start

  1. Oct 2, 2008 #1
    1. The problem statement, all variables and given/known data
    1. Circle all insoluble compounds. (5 pts) (-1 for each incorrect, to a max total of -5)

    Na3PO4 CaCl2 HgCl2 LiNO3 , PbBr2 , PbCO3

    (NH4)3PO4 CuCl2 Fe(OH)2 MgSO4 AgNO3 K2CO3

    Given the insoluble compounds, and important exceptions list... how do I follow the question above?

    2. Write the balanced net ionic equation for precipitation of CaCO3 when
    aqueous solutions of Li2CO3 and CaCl2 are mixed. (2 pt)

    Ca2+ (aq) + CO32- (aq) -> CaCO3 (s)

    How do I do the question above? What is the things to do in order to write out the net ionic equation?

    1. When ammonia is combined with hydrochloric acid, the products are:
    a. NH4Cl + H2O (correct)
    b. NH4Cl + OH- + H2
    c. NH3Cl + H2O
    d. NH3Cl + H2
    e. NH4Cl + OH-

    2. Considering the following reaction, what is undergoing oxidation?
    Fe + ZnCl2 -> FeCl2 + Zn
    a. Fe and Cl2
    b. Fe and Zn
    c. Fe (correct)
    d. Zn
    e. Cl2

    3. Balance the following net ionic redox reaction:
    Ca + Sb3+ -> Ca2+ + Sb
    a. Ca + Sb3+ -> Ca2+ + Sb
    b. 2Ca + Sb3+ -> Ca2+ + 3Sb
    c. Ca + 2Sb3+ -> 3Ca2+ + Sb
    d. 3Ca + 2Sb3+ -> 3Ca2+ + 2Sb (correct)
    e. 2Ca + 3Sb3+ -> 2Ca2+ + 3Sb

    I've looked around my textbook for examples but couldn't find anything. What chapters or phrases should I be looking for to do these problems? These are study guide questions... and I need to learn how to do them soon.... I'm so lost in my Chem class..
  2. jcsd
  3. Oct 2, 2008 #2
    You should have a table reffering to insoluble substances in H2O i assume, i do... :/ like PbI is insoluble(if i remember correctly, i don't have the table in front of me) there are also a set of 5 rules...

    as for net ionic equations, look in the "Redox Reduction Reactions" Should be in there, or check the glossary section of your text book, I'm not very good at them ^.^
  4. Oct 2, 2008 #3


    User Avatar

    Staff: Mentor

    OK for tables, they should be in the book or easy to google, but no such thing as PbI (PbI2 it is).

    Net ionic equations have nothing in common with redox reactions. Net ionic means just that they contain only ions that take part in the reaction (none of the spectators).
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