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Problem 48a
A 100.0-mL buffer solution is 0.175 M in HClO and 0.150 M in NaClO. a. What is the initial pH of this solution?
Problem 48b
A 100.0-mL buffer solution is 0.175 M in HClO and 0.150 M in NaClO. b. What is the pH after addition of 150.0 mg of HBr?
Problem 48c
A 100.0-mL buffer solution is 0.175 M in HClO and 0.150 M in NaClO. c. What is the pH after addition of 85.0 mg of NaOH?
- For each solution, calculate the initial and final pH after adding 0.010 mol of HCl: a. 500.0 mL of pure water b. 500.0 mL of a buffer solution that is 0.125 M in HC2H3O2 and 0.115 M in NaC2H3O2 c. 500.0 mL of a buffer solution that is 0.155 M in C2H5NH2 and 0.145 M in C2H5NH3Cl.
Problem 49
Problem 50
For each solution, calculate the initial and final pH after adding 0.010 mol of NaOH. a. 250.0 mL of pure water b. 250.0 mL of a buffer solution that is 0.195 M in HCHO2 and 0.275 M in KCHO2 c. 250.0 mL of a buffer solution that is 0.255 M in CH3CH2NH2 and 0.235 M in CH3CH2NH3Cl
- A 350.0-mL buffer solution is 0.150 M in HF and 0.150 M in NaF. What mass of NaOH can this buffer neutralize before the pH rises above 4.00? If the same volume of the buffer were 0.350 M in HF and 0.350 M in NaF, what mass of NaOH could be handled before the pH rises above 4.00?
Problem 51
Problem 52
A 100.0-mL buffer solution is 0.100 M in NH3 and 0.125 M in NH4Br. What mass of HCl can this buffer neutralize before the pH falls below 9.00?
Problem 53a
Determine whether or not the mixing of each pair of solutions results in a buffer. a. 100.0 mL of 0.10 M NH3; 100.0 mL of 0.15 M NH4Cl
Problem 53b
Determine whether or not the mixing of each pair of solutions results in a buffer. b. 50.0 mL of 0.10 M HCl; 35.0 mL of 0.150 M NaOH
Problem 53c
Determine whether or not the mixing of each pair of solutions results in a buffer. c. 50.0 mL of 0.15 M HF; 20.0 mL of 0.15 M NaOH
Problem 53d
Determine whether or not the mixing of each pair of solutions results in a buffer. d. 175.0 mL of 0.10 M NH3; 150.0 mL of 0.12 M NaOH
Problem 53e
Determine whether or not the mixing of each pair of solutions results in a buffer. e. 125.0 mL of 0.15 M NH3; 150.0 mL of 0.20 M NaOH
Problem 54a,b,d
Determine whether or not the mixing of each pair of solutions results in a buffer. a. 75.0 mL of 0.10 M HF; 55.0 mL of 0.15 M NaF b. 150.0 mL of 0.10 M HF; 135.0 mL of 0.175 M HCl d. 125.0 mL of 0.15 M CH3NH2; 120.0 mL of 0.25 M CH3NH3Cl
Problem 54c
Determine whether or not the mixing of each pair of solutions results in a buffer. c. 165.0 mL of 0.10 M HF; 135.0 mL of 0.050 M KOH
Problem 54e
Determine whether or not the mixing of each pair of solutions results in a buffer. e. 105.0 mL of 0.15 M CH3NH2; 95.0 mL of 0.10 M HCl
Problem 55a
Blood is buffered by carbonic acid and the bicarbonate ion. Normal blood plasma is 0.024 M in HCO3- and 0.0012 M H2CO3 (pKa1 for H2CO3 at body temperature is 6.1).
a. What is the pH of blood plasma?
- If the volume of blood in a normal adult is 5.0 L, what mass of HCl can be neutralized by the buffering system in blood before the pH falls below 7.0 (which would result in death)?
Problem 55b
Problem 55c
Blood is buffered by carbonic acid and the bicarbonate ion. Normal blood plasma is 0.024 M in HCO3- and 0.0012 M H2CO3 (pKa1 for H2CO3 at body temperature is 6.1).
c. Given the volume from part (b), what mass of NaOH can be neutralized before the pH rises above 7.8?
Problem 56
The fluids within cells are buffered by H2PO4- and HPO42- . b. Could a buffer system employing H3PO4 as the weak acid and H2PO4- as the weak base be used as a buffer system within cells? Explain.
- Which buffer system is the best choice to create a buffer with pH = 7.20? For the best system, calculate the ratio of the masses of the buffer components required to make the buffer: HC2H3O2/KC2H3O2, HClO2/KClO2, NH3/NH4Cl, or HClO/KClO.
Problem 57
Problem 58
Which buffer system is the best choice to create a buffer with pH = 9.00? For the best system, calculate the ratio of the masses of the buffer components required to make the buffer. HF/KF HNO2/KNO2 NH3/NH4Cl HClO/KClO
Problem 59a
A 500.0-mL buffer solution is 0.100 M in HNO2 and 0.150 M in KNO2. Determine if each addition would exceed the capacity of the buffer to neutralize it. a. 250 mg NaOH
Problem 59b
A 500.0-mL buffer solution is 0.100 M in HNO2 and 0.150 M in KNO2. Determine if each addition would exceed the capacity of the buffer to neutralize it. b. 350 mg KOH
Problem 59c
A 500.0-mL buffer solution is 0.100 M in HNO2 and 0.150 M in KNO2. Determine if each addition would exceed the capacity of the buffer to neutralize it. c. 1.25 g HBr
Problem 59d
A 500.0-mL buffer solution is 0.100 M in HNO2 and 0.150 M in KNO2. Determine if each addition would exceed the capacity of the buffer to neutralize it. d. 1.35 g HI
Problem 60
A 1.0-L buffer solution is 0.125 M in HNO2 and 0.145 M in NaNO2. Determine the concentrations of HNO2 and NaNO2 after the addition of each substance: a. 1.5 g HCl b. 1.5 g NaOH c. 1.5 g HI
Problem 61a
The graphs labeled (a) and (b) show the titration curves for two equal-volume samples of monoprotic acids, one weak and one strong. Both titrations were carried out with the same concentration of strong base.
(i) What is the approximate pH at the equivalence point of each curve?
Problem 61b
The graphs labeled (a) and (b) show the titration curves for two equal-volume samples of monoprotic acids, one weak and one strong. Both titrations were carried out with the same concentration of strong base.
(ii) Which graph corresponds to the titration of the strong acid and which one to the titration of the weak acid?
- Two 25.0-mL samples, one 0.100 M HCl and the other 0.100 M HF, are titrated with 0.200 M KOH. a. What is the volume of added base at the equivalence point for each titration?
Problem 62
Problem 62b
Two 25.0-mL samples, one 0.100 M HCl and the other 0.100 M HF, are titrated with 0.200 M KOH. b. Is the pH at the equivalence point for each titration acidic, basic, or neutral?