Question

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 0.240*M* in
HCHO2 and 0.280*M* 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 0.305*M* in
CH3CH2NH2 and 0.285*M* in CH3CH2NH3Cl, calculate the initial
pHand the final pH after adding 0.010 mol of NaOH.

Answer #1

a)

pure water : pH = 7.00

moles NaOH = 0.010

[OH-]= 0.010 mol/ 0.300 L=0.0333 M

**pOH = - log (0.0333)= 1.47
pH = 14 - pOH = 14 - 1.47=12.53**

b)

Ka = 1.8 x 10^-4

pKa = 3.74

moles formic acid = 0.240 M x 0.300 L=0.072

moles formate = 0.280 M x 0.300 L =0.084

the effect of the added 0.010 mol OH- would be to decrease the
moles of formic acid by 0.010 and increases the moles of formate by
0.010 by the reaction

HCOOH + OH- = HCOO-

moles HCOOH = 0.072 - 0.010 = 0.062

moles HCOO- = 0.084 + 0.010=0.094

concentration HCOOH = 0.062 / 0.300 L=0.206 M

concentration HCOO- = 0.094 / 0.300 =0.313

**pH = 3.74 + log 0.313 / 0.206 = 3.92**

**pH=3.92 (final pH)**

c)

Kb of ethylammine = 4.3 x 10^-4

pKb = 3.37

pOH = 3.37 + log 0.285 / 0.305 = 3.34

pH = 14 - 3.34 =10.7 **( initial pH)**

moles CH3CH2NH3+ = 0.285 x 0.300 L=0.0855

moles CH3CH2NH2 = 0.305 x 0.300 L=0.0915

CH3CH2NH3+ + OH- = CH3CH2NH2 + H2O

moles CH3CH2NH3+ = 0.0855 - 0.010 =0.0755

moles CH3CH2NH2 = 0.0915 + 0.010 =0.1015

concentration CH3CH2NH3+ = 0.0755 / 0.300 =0.251 M

concentration CH3CH2NH2 = 0.1015 / 0.300=0.338 M

**pOH = 3.37 + log 0.251 /
0.338=3.24**

**pH = 10.76 (final pH)**

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.
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 0.010 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 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...

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

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...

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.

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 in the final pH after adding 0.200 moles of NaOH for
300.0 M L of a buffer solution that is 0.2551 m in
ch3ch2nh2 AND 0.2351 in ch3ch2nh3cl calculate the initial pH and
the final pH after adding 0.020 moles of naoh KB equal 5.6 x 10 to
the negative 4

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