Chemistry, 26.07.2019 15:00 emily5400

What is the ph of 0.175 m methylammonium bromide, ch3nh3br? (kb of ch3nh2 = 4.4 × 10−

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By using ICE table:

CH3NH3+ + H2O → CH3NH4 2+ + OH-

initial 0.175 0 0

change -X +X +X

Equ (0.175-X) X X

when: Ka = Kw / Kb

= (1 x 10^-14) / (4.4 x 10^-4) = 2.3 x 10^-11

when Ka = [CH3NH42+][OH-] / [CH3NH3+]

by substitution:

2.3 x 10^-11 = X^2 / (0.175 - X ) by solving for X

∴ X = 2 x 10^-6

∴[OH-] = 2 x 10^-6

∴POH = -㏒[OH-]

= -㏒(2 x 10^-6)

= 5.7

when PH + POH = 14

∴PH = 14 - 5.7 = 8.3

Answer from: Shazrts2371

The pH of the solution is calculated to be 11.9.

First, we must set up the ICE table of the reaction;

CH3NH2(aq) + H2O(l) ⇄ CH3NH3^+ (aq) + OH^-(aq)

I 0.175 0 0

C -x +x +x

E 0.175 - x x x

We have to find the Ka as follows;

Ka = [ CH3NH3^+] [OH^-]/[CH3NH2]

Ka = x^2/0.175 - x

Substituting values;

4.4 × 10−4 = x^2/0.175 - x

4.4 × 10−4 (0.175 - x ) = x^2

7.7 × 10−5 - 4.4 × 10^−4x = x^2

x^2 + 4.4 × 10^−4x - 7.7 × 10^−5 = 0

x = 0.0086 M

Now, pOH = -log(0.0086 M) = 2.1

pH = 14 - 2.1 = 11.9

Hence, the pH of the solution is calculated to be 11.9.

Learn more about pH: link

Answer from: Quest

they it depends on if one believes about radioactivity, they make a geiger counter beep but maybe it was going to beep anyway electronics do wierd things all the time or it was programmed to beep near certain metals.

Answer from: Quest

The correct answer is "atomic weight".

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What is the ph of 0.175 m methylammonium bromide, ch3nh3br? (kb of ch3nh2 = 4.4 × 10−...

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