Question

For each of the following solutions, calculate the initial pH and the final pH after adding 0.0100 mol of NaOH.

**Part A**

For 300.0 mL of pure water, calculate the initial pH and the final pH after adding 0.0100 mol of NaOH.

Express your answers using two decimal places separated by a comma.

**Part B**

For 300.0 mL of a buffer solution that is 0.210 *M* in
HCHO2 and 0.280 *M* in KCHO2, calculate the initial pH and
the final pH after adding 0.0100 mol of NaOH(Ka=1.8⋅10−4).

Express your answers using two decimal places separated by a comma.

**Part C**

For 300.0 mL of a buffer solution that is 0.2551 *M* in
CH3CH2NH2 and 0.2251 *M* in CH3CH2NH3Cl, calculate the
initial pH and the final pH after adding 0.0100 mol of
NaOH(Kb=5.6⋅10−4).

Express your answers using two decimal places separated by a comma.

Answer #1

Part A)

Initial pH = 7

Moles of NaOH added = 0.01

Volume of solution = 300 mL = 0.3 L

=> [NaOH] = 0.01 / 0.3 = 0.0333 M (For all the parts)

NaOH is a strong base. Hence, it dissociates completely in aquous solution

[OH-] from NaOH = 0.0333 M

pOH = - log [OH-] = - log (0.0333) = 1.477

**pH = 14 - pOH = 12.52**

Part B)

Ka = 1.8 x 10^-4

=> pKa = 3.745

Initial pH = pKa + log ([KCHO2] / [HCHO2])

**=> pH = 3.745 + log (0.28 / 0.21) = 3.87**

Final pH

[NaOH] = 0.0333 M

Final pH = pKa + log ([KCHO2] + [NaOH] / [HCHO2] - [NaOH])

**pH = 3.745 + log (0.28 + 0.0333 / 0.21 - 0.0333) =
3.99**

Part C)

pKb = 3.25

Initially

pOH = pKb + log ([CH3CH2NH3Cl] / [CH3CH2NH2])

=> pOH = 3.25 + log (0.2251 / 0.2551) = 3.20

**pH = 14 - pOH = 10.80,**

Finally

pOH = pKb + log ([CH3CH2NH3Cl] - [NaOH] / [CH3CH2NH2] + [NaOH])

=> pOH = 3.25 + log (0.2251 - 0.0333 / 0.2551 + 0.0333) = 3.07

**pH = 14 - pOH = 10.93**

For each of the following solutions, calculate the initial pH
and the final pH after adding 0.010 mol of NaOH.
Part A: For 270.0 mL of a buffer solution that is 0.205 M in
HCHO2 and 0.305 M in KCHO2, calculate the initial pH and the final
pH after adding 0.010 mol of NaOH. Express your answers using two
decimal places separated by a comma.
Part B: For 270.0 mL of a buffer solution that is 0.285 M in
CH3CH2NH2...

For each of the following solutions, calculate the initial pH
and the final pH after adding 0.010 mol of NaOH .
Part B
250.0 mL of a buffer solution that is 0.200 M in HCHO2 and 0.305
M in KCHO2
Part C
250.0 mL of a buffer solution that is 0.265 M in CH3CH2NH2 and
0.245 M in CH3CH2NH3Cl
Express your answers using two decimal places separated by a
comma.

For each of the following solutions, calculate the
initial pH and the final pH after adding 0.0200 mol of
NaOH.
Part A
For 290.0 mL of pure water, calculate the initial pH and the
final pH after adding 0.0200 mol of NaOH.
Express your answers using two decimal places separated by a
comma.
Answer: pHinitial, pHfinal = 7.00,12.84
Part B
For 290.0 mL of a buffer solution that is 0.200 M in
HCHO2 and 0.310 M in KCHO2, calculate the...

Exercise 16.50
For each of the following solutions, calculate the initial pH
and the final pH after adding 0.0200 mol of NaOH.
Part A
For 300.0 mL of pure water, calculate the initial pH and the
final pH after adding 0.0200 mol of NaOH.
Express your answers using two decimal places separated by a
comma.
pHinitial, pHfinal =
7.00,12.82
SubmitMy AnswersGive
Up
Correct
Part B
For 300.0 mL of a buffer solution that is 0.210 M in
HCHO2 and 0.310...

For each of the following solutions, calculate the initial pH
and the final pH after adding 0.0150 mol of NaOH.
For 270.0 mL of pure water, calculate the initial pH and the
final pH after adding 0.0150 mol of NaOH.
For 270.0 mL of a buffer solution that is 0.240 M in
HCHO2 and 0.310 M in KCHO2, calculate the initial pH and
the final pH after adding 0.0150 mol of NaOH(Ka=1.8⋅10−4).
For 270.0 mL of a buffer solution that...

For each of the following solutions, calculate the initial pH
and the final pH after adding 0.010 mol of NaOH.
For 300.0mL of pure water, calculate the initial pH and the
final pH after adding 0.010 mol of NaOH.
For 300.0mL of a buffer solution that is 0.240M in
HCHO2 and 0.280M in KCHO2, calculate the initial pH and
the final pHafter adding 0.010 mol of NaOH.
For 300.0mL of a buffer solution that is 0.305M in
CH3CH2NH2 and 0.285M...

A) For 480.0 mL of pure water, calculate the initial pH and the
final pH after adding 0.010 mol of HCl. Express your answers using
two decimal places separated by a comma.
B) For 480.0 mL of a buffer solution that is 0.150 M in
HC2H3O2 and 0.135 M in NaC2H3O2, calculate the initial pH
and the final pH after adding 0.010 mol of HCl.
Express your answers using two decimal places separated by a
comma.
C) For 480.0 mL...

For each of the following solutions, calculate the initial pH
and the final pH after adding 0.005 mol of NaOH.
For 260.0 mL of a buffer solution that is 0.265 M in
CH3CH2NH2 and 0.235 M in CH3CH2NH3Cl, calculate the
initial pH and the final pH after adding 0.005 mol of NaOH.

For each of the following solutions, calculate the initial pH
and the final pH after adding 0.010 mol of NaOH.
c) For 220.0 mL of a buffer solution that is 0.285 M in
CH3CH2NH2 and 0.255 M in CH3CH2NH3Cl, calculate the
initial pH and the final pH after adding 0.010 mol of NaOH.

For each of the following solutions, calculate the initial pHand
the final pH after adding 0.005 mol of NaOH.
260.0 mL of a buffer solution that is 0.225 M in HCHO2 and 0.315
M in KCHO
260.0 mL of pure water
260.0 mL of a buffer solution that is 0.275 M in CH3CH2NH2 and
0.245 M in CH3CH2NH3Cl

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