1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
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: Mass of ammonia through nitrate concentration problem

  1. Jun 11, 2017 #1
    1. The problem statement, all variables and given/known data
    The nitrate concentration in an aquifer is 20 ppm, and its volume is ten million
    liters. What mass of ammonia upon oxidation would have produced this mass of
    nitrate? [Hint: The moles of nitrogen in reactant and product are identical.]

    2. Relevant equations
    Possibly 1mg/L & NH3+O2---->NO3-

    3. The attempt at a solution
    Since 1mg/L equals 1ppm then I'd get a 2*10^8mg for nitrate mass. And NH3+O2---->NO3- (through aerobic contitions and nitrification, idk if this is applicable >: ) then the 1:1 ratio means there's an equal amount of ammonium?
  2. jcsd
  3. Jun 11, 2017 #2


    User Avatar

    Staff: Mentor

    1:1 in terms of moles, not mass.
  4. Jun 11, 2017 #3


    User Avatar
    Homework Helper
    Gold Member

    Why not be a bit simpler? You have 20 parts per million, then if you have 1 million, 20 parts of it is 20, 20 parts per million of 10 million is 200!

    We have a disagreement there by a factor of 1000.

    After you are sure about that, you have to convert the nitrate mass into ammonium mass as Borek and the question itself have indicated.

    Do they really use these units? I suppose it is in order to give the general public an idea they can appreciate of the concentrations?

    For anyone knowing a bit of chemistry It sounds rather odd - ppm would be okay to give as a formula for somebody to weigh out grams to be put in a lake or something. You can weigh out sodium nitrate or calcium nitrate, but there is no substance called just 'nitrate' that you can weigh out.
  5. Jun 11, 2017 #4


    User Avatar

    Staff: Mentor

    Come on, in many places we report things using proxies - like amount of P2O5 in fertilizer. For me NO3- doesn't sound worse than ammonia or just nitrogen, the meaning is obvious
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted