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descriptive chemistry question

Discussion in 'Off Topic [BG]' started by slick519, Nov 25, 2005.


  1. slick519

    slick519

    Aug 11, 2001
    Salem, Or
    what would be the product of the reaction between...

    sodium nitrite and hydrochloric acid?

    also...

    carbon dioxide gas bubbled through lithium hydroxide?

    I am studying for my AP chemistry class, and we are doing a unit on acid base neutralization reactions, though neither of the above seem to be an example of acid base neutralization. Overall, i think it is just a basic metathesis reaction, but i am not sure

    any help would be appreciated!

    peter
     
  2. Ericman197

    Ericman197

    Feb 23, 2004
    Iowa
    NaNO2 + HCl yields HNO2 + NaCl

    This reaction produces nitrous acid, which is unstable and as such blah blah blah

    CO2 + 2LiOH yields Li2CO3 and H2O

    This reaction produces lithium carbonate. Lithium dihydrate is used to absorb CO2 blah blah blah
     
  3. Dan1099

    Dan1099 Dumbing My Process Down

    Aug 7, 2004
    Michigan
    I didn't try to balance it, but that looks right to me. Good ole' AP chem. The AP test got me through two years of chem at my university.

    EDIT: Dlloyd has answered it much more accurately. Oh how one forgets about solubilities and pKa's and all sorts of things.
     
  4. Brad Barker

    Brad Barker Supporting Member

    Apr 13, 2001
    berkeley, ca
    do you also have to keep in mind solubility rules?
     
  5. slick519

    slick519

    Aug 11, 2001
    Salem, Or
    wowza. I posted this same question on a "chemistry" forum board and got bumpkiss.

    This only reconfirms my notion that this is indeed one of the more intelligent forum boards on the internet.

    thank you very much, and i will probably have some more later....


    Peter
     
  6. bassman314

    bassman314 I seem to be a verb, an evolutionary process... Gold Supporting Member

    Mar 13, 2005
    Bay Area, CA
    except not...

    It's basic stoichiometry...

    And I can't remember my solubility rules, but those looked right... some of it will be aqueos, some will be solid..
     
  7. slick519

    slick519

    Aug 11, 2001
    Salem, Or
    welll... kinda stoichiometry... but it is descriptive chemistry. And, yes, when referenced with the solubility and gas charts... everything is either aqueous or liquid (besides the noted gaseous elements) the HNO2 is classified as a liquid because it doesnt ionize completely, just like all other weak acids.
     
  8. Figjam

    Figjam

    Aug 5, 2003
    Boston, MA
    As far as solubility for these you just have to know that Na is soluble and H Cl is a strong acid so you should write it as its ions.
     
  9. tribal3140

    tribal3140 Banned

    Nov 9, 2004
    near detroit...uh
    I am one to admittedly, but neurophysiology and electro physiology were my bag baby.
    sodium, potassium, and calcuim ions diffusing across nueral mylenated and unmylenated semi permeable membranes.
    the good old days! :ninja:
     
  10. Ericman197

    Ericman197

    Feb 23, 2004
    Iowa
    Well, there is some organic chemistry involved. Although inorganic in nature, the reaction used to produce HNO2 is very common in organic chemistry. It is an unstable weak acid, so if one were to seperate the ions in the equations, HNO2 would stay together as a liquid. Everything else is pretty straightfoward: everything is aqueous except water and carbon dioxide.
     
  11. slick519

    slick519

    Aug 11, 2001
    Salem, Or
    hey ericman, where did you learn all of your chem? Just your high school chemistry course, or are you pursuing it in college?

    Peter
     
  12. Ericman197

    Ericman197

    Feb 23, 2004
    Iowa
    I didn't take chem in high school but I'm taking inorganic chem I right now. You could say I "read ahead."
     
  13. dlloyd

    dlloyd zzzzzzzzzzzzzzz

    Apr 21, 2004
    Scotland
    Nope.
     
  14. dlloyd

    dlloyd zzzzzzzzzzzzzzz

    Apr 21, 2004
    Scotland
    *Edited*

    I disagree.
     
  15. Figjam

    Figjam

    Aug 5, 2003
    Boston, MA
    Hes got it mostly right. It is weak, therefore it would stay in HNO2 form, no?
     
  16. slick519

    slick519

    Aug 11, 2001
    Salem, Or
    well, what eric said about the HNO2 is correct, according to my teacher. When writing a net ionic equation, any acid that does not completely ionize, therefore any weak acid, is written as a liquid.

    technically, there is a continuous reaction going on, but for ease of writing equations, the AP board, at least, tests students with that method.
     
  17. Brad Barker

    Brad Barker Supporting Member

    Apr 13, 2001
    berkeley, ca

    i don't my my acids from my elbow! :p


    man, it feels like forever since i had a chem class, when in reality it was just last spring. :eek:
     
  18. Ericman197

    Ericman197

    Feb 23, 2004
    Iowa
    I know it's not an organic reaction; it's a reaction that may be used for organic purposes. See slick's comment for the liquid HNO2 dealio. Whatever it is, it's written as a liquid.
     
  19. dlloyd

    dlloyd zzzzzzzzzzzzzzz

    Apr 21, 2004
    Scotland
    (edited to remove grouchiness and to improve relevance with the initial post.)

    CO2 bubbled through a lithium hydroxide solution

    CO2 + 2Li+ + 2OH- -----> 2Li+ + (CO3)2- +H2O

    Carbonic acid is a weak diprotic acid, but will be more or less completely dissociated at the pH at which this reaction will take place. Lithium carbonate is moderately soluble.

    As you keep bubbling CO2 in, the pH continues to drop and it becomes more favourable for the formation of the bicarbonate ion.

    H+ + (CO3)2- <-----> HCO3- pKa = 10.3

    If you keep bubbling it in, you'll start getting carbonic acid

    H+ + HCO3- <-----> H2CO3 pKa = 6.3

    The pKa is the negative log(10) of the dissociation constant Ka of the weak acid. It basically tells you the pH at which half of the solution is in the acid species and half is in the base species.

    sodium nitrite and hydrochloric acid

    Na+ + NO2- + H+ + Cl- -------> HNO2 + Na+ + Cl-

    That's what you'd get if you added a small amount of sodium nitrite to excess hydrochloric acid. However, if you're talking about a complete reaction (i.e. equal concentrations of sodium nitrite and hydrochloric acid to start with), you'll get this...

    Na+ + NO2- + H+ + Cl- -------> H+ + NO2- + Na+ + Cl-

    Nitrous acid is weak, but has a pKa of around 3.34, meaning it more or less fully dissociates at neutral pH.

    The end pH will depend on the initial concentrations of the substrates.

    *Hopefully the final edit*

    If you haven't been taught about equilibrium constants yet, ignore the "howevers" in this post and just go for the bits in blue.
     
  20. Thor

    Thor Moderator Staff Member Gold Supporting Member

    Now ask Dlloyd where the dilithium crystals can be found ...
    :ninja: