Chemistry;

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for a solution of the weak base, 0.075 M ethylamine C2H5NH2(aq), the hydroxide ion concentration (OH-) is 6.6x10^-3 M. Assume that temperature is constant and volumes are additive.

a. Write the equilibrium dissociation equation.

b. What's the pH of 0.075 M C2H5NH2(aq)?

c. What's the value of Kb?


Please show your work on how you calculate it so I can see how you figured it out. Thanks.

  • Chemistry; -

    C2H5NH2 + HOH ==> C2H5NH3^+ + OH^-

    You know OH^-; therefore,
    pOH = -log(OH^-) and
    pH + POH = pK2w = 14. Solve for pH.

    Write the Kb expression
    Substitute OH^- = 0.0066
    (C2H5NH3^+) = 0.0066
    (C2H5NH2) = 0.075-0.0066
    Solve for Kb.

  • Chemistry; -

    Thanks! This was very helpful.

  • corrn; type -

    pH + pOH = pKw = 14 (and not pK2w)
    (Kw has no K2).

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