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

Rate law seconds and concentration

  1. Jun 22, 2004 #1


    User Avatar

    could you check this?

    AB(g) → A(g) + B(g)

    Rate = k[AB]^2
    k = 0.2L/mol∙S

    How long will it take for [AB] to reach 1/3 (one third) of its initial concentration of 1.50M? What is [AB] after 10.0 seconds?

    2nd order overall reaction so:
    part A
    1/[A] - 1/[A]o = (k)(t)
    1/0.5 - 1/1.50 = (0.2)(t)
    6.667 = t

    part B
    1/[A] - 1/1.5 = (0.2)(10 s)
    [A] = 0.375
  2. jcsd
  3. Jun 22, 2004 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Correct, and correct !

    Just remember to put in the units; time in seconds and concentration in mol/L or M (molar).
  4. Jun 22, 2004 #3


    User Avatar

    okie dokie. thanks.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook