Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Balanced Net Ionic Equation

  1. Aug 14, 2008 #1
    1. The problem statement, all variables and given/known data
    The balanced net ionic equation for precipitation of CaCO3 when aqueous solutions of Na2CO3 and CaCl2 are mixed is _____.

    2. Relevant equations
    Not sure of any

    3. The attempt at a solution
    I'm not sure how to get a "net ionic equation." I took chemistry 2 years ago and looking to take another course in it. Unfortunately I forgot a lot of chemistry so I'm looking to do some extra work to help me remember it. The product side would be 2NaCl + CaCO3, but how do I find the "net ionic equation" and not just an equation with reagents to product?
  2. jcsd
  3. Aug 15, 2008 #2
    In ionic equations, you need only consider those ions that 'change' in the solution. 'change' in your questions refers to a change of state from aqueous to solid. spectator ions(those which remain 'unchanged') should be ignored and you have to ensure that the charges are balanced, that is the net charge on the left hand side of the equation is equal to that in the right hand side.

    an example:
    Pb(NO3)2 + NaBr will give the insoluble solid PbBr2

    in terms of ions:

    Pb2+(aq) -----> Pb2+(s)
    Br-(aq) -----> Br-(s)

    but Na+(aq) remains as such in solution
    as well as NO3 (aq)-

    therefore the net ionic equation is:

    Pb2+(aq) + 2Br-(aq) ---> PbBr2 (s)

    the charges are balanced and there are no spectator ions.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook