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NikAS [45]
3 years ago
11

The ph of a 0.24 m solution of dimethylamine is 12.01. calculate the kb value for dimethylamine.

Chemistry
1 answer:
vlada-n [284]3 years ago
8 0
1- First we will get the value of POH from:

PH + POH = 14 

and we have PH = 12.01

∴ POH = 14 - 12.01 = 1.99 

2- Then we need to get the concentration of OH:

when POH = -㏒[OH]

           1.99 = -㏒[OH]

∴[OH] = 0.01 M

now we have the concentration at Equ by subtracting from the initial concentration of OH  = 0.24 M

∴ [OH] = 0.24 - 0.01 = 0.23 M

∴ Kb = (0.01)^2 /  0.22977 M

∴ Kb value = 4.4 x 10^-4

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\large \boxed{\text{17.mL}}

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\begin{array}{rcrrcl}p_{1}& =& \text{123.5 kPa}\qquad & V_{1} &= & \text{25 L} \\p_{2}& =& \text{179.9 kPa}\qquad & V_{2} &= & ?\\\end{array}

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\begin{array}{rcl}123.5 \times 25 & =& 179.9V_{2}\\3088 & = & 179.9V_{2}\\V_{2} & = &\dfrac{3088}{179.9}\\\\& = &\textbf{17 L}\\\end{array}\\\text{The new volume of the gas is } \large \boxed{\textbf{17 L}}

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