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Homework Help: RICE Tables

  1. May 12, 2007 #1
    when you're doing RICE tables for weak acid/base reactions, when do you neglect x? thanks for ANY input :biggrin:
    Last edited: May 12, 2007
  2. jcsd
  3. May 12, 2007 #2


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    What are RICE tables? What does "x" mean?
  4. May 12, 2007 #3


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    I heard these things called "ICE" tables, but not "RICE" tables.... further along I have used these to calculate equilibrium in a system. ICE stands for INITIAL CHANGE EQUILIBRIUM. I never used these things when involving acids/bases.

    Here is what Wikipedia sais about RICE tables:

    An Indonesian rice table (in Dutch, rijsttafel) consists of rice accompanied by several, often spicy side dishes served buffet-style. Popular side dishes include egg rolls, sambals, satay, fish, fruit, vegetables, pickles, and nuts. It is a Dutch colonial adaptation of the Indonesian makan besar, and popular in both Indonesia and the Netherlands.

    The number of side dishes depends mainly on the number of guests; in a restaurant, as many as two dozen side dishes may be served. In many restaurants, the side dishes are brought to the guests' table, covering the table with the many small plates.
  5. May 12, 2007 #4
    maybe chemistry has changed a bit since you guys were in highschool.
    because we calculate weak acids/bases by RICE tables: Reaction, Initial, Change, and Equilibrium; like ssb said.
    ok;so never mind.
    thanks anyways :)
  6. May 12, 2007 #5


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    I asked because I never heard of any such acronymic designation. Back several years ago, we used stoichiometry, accounting for concentrations, moles, and some intermediate level Algebra.
  7. May 23, 2007 #6
    haha. you can neglect x if hte 5% rule is valid
  8. May 23, 2007 #7
    for example:

    dissociation of HF, Ka = 7.2E-4

    HF <-> H+ + F-
    I .1 0 0
    C -x +x +x
    E .1-x x x

    Ka = 7.2E-4 = x^2/(.1-x)

    - assume 5% rule is valid and x is a very small number in comparison to .1

    therefore, 7.2E-4 = x^2/.1

    -solve for x, which ends up being about 8.5E-3 which is small in comparison to .1 proving the 5% rule to be valid.

    -therefore x can be beglected and the [H+] = x = 8.5E-3
  9. May 29, 2007 #8
    We still use ICE tables they haven't meleted yet...haha......
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