General Chemistry
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Determine the pH for the following solution: 25.0 mL 0.17 M HIO with 35.0 mL 0.19 M NaIO (Ka HIO = 2.3×10−11)
Identify whether to add KOH or HBr to the buffer mixture to adjust the pH to 9.56. The buffer solution of 1-L initially contains 0.500 M in CH3NH2 and 0.500 M in CH3NH3Br. Calculate the mass of the correct reagent needed.
A buffer solution is prepared using HF and F–. HF has a pKa of 3.16 and the buffer has a pH of 3.35. Determine which of the following is applicable at pH 3.35 without performing any calculations.
Acetic acid is a weak acid that dissociates into acetate ion and hydronium ions in solutions:
CH3COOH(aq) + H2O(l) ⇌ H3O+(aq) + CH3COO-(aq)
The value of the dissociation constant (Ka) for acetic acid is 1.78×10-5. If you require a buffer of pH 5.25, what would be the ratio of [CH3COO-]/[CH3COOH] that you would use?
If you need to prepare a buffer with a pH of 8.8, which one of the following acid/conjugate base pairs would you choose?
Consider a 250.0 mL solution of 0.20 M propanoic acid. Calculate the mass of sodium propanoate needed to produce a buffer with a pH of 5.11 assuming the volume does not change.
Calculate the pH of the solution that results from each mixture. a. 50.0 mL of 0.15 M HCHO2 with 75.0 mL of 0.13 M NaCHO2
Consider a solution that contains 25 g of CH3COOH and 15 g of NaCH3COO in a 250.0 mL of solution
Calculate the pH using the Henderson–Hasselbalch equation.
Use the Henderson–Hasselbalch equation to calculate the pH of each solution.
c. a solution that contains 10.0 g of HC2H3O2 and 10.0 g of NaC2H3O2 in 150.0 mL of solution
A buffer contains a weak acid, HA, and its conjugate base. The weak acid has a pKa of 5.7, and the buffer has a pH of 5.2. Without doing a calculation, choose which of these possibilities is correct at pH 5.2.
How would you prepare a buffer solution made of HC7H5O2 and NaC7H5O2 with a pH of 4.10? (Ka HC7H5O2 = 6.5×10−5)
Calculate the pH of a buffer consisting of 0.130 mol of propanoic acid and 0.160 mol of sodium propanoate in 1.00 L. The pKa of propanoic acid is 4.87.
0.125 M HCN and 0.140 M NaCN are mixed to produce a 125.0 mL buffer solution. Determine the pH of the solution if 125.0 mg of HCl was added. (Ka HCN = 4.90×10−10)
0.125 M HCN and 0.140 M NaCN are mixed to produce a 125.0 mL buffer solution. Determine the initial pH of the solution. (Ka HCN = 4.90×10−10)
A 0.275 L sample of HBr gas was dissolved in a solution at 25°C and 730 mmHg. The solution initially contained 1.740 g of Na2HPO4 and 0.125 L of water. Calculate the pH of the resulting solution if the pKa of dihydrogen phosphate is 7.21.
The ratio of hydrogen phosphate to dihydrogen phosphate in renal tubular and intracellular fluids is maintained at 1.55 by the body. The phosphate buffer system works in the internal fluids of all cells. Extra hydroxide and hydrogen ions that enter the intracellular fluid are neutralized by this buffer. Calculate the pH of the phosphate buffer system (Ka for dihydrogen phosphate at room temperature is 6.17×10−8).
Calculate the ratio of the volumes of 1.25 M sodium glycolate (NaC2H3O3) and 1.25 M glycolic acid (C2H4O3) necessary to make a buffer of pH 4.25. The pKa of C2H4O3 is 3.83.
Calculate the pH of a buffer solution that is 0.275 M glycolic acid (C2H4O3) and 0.550 M sodium glycolate (NaC2H3O3). The pKa of C2H4O3 is 3.83.
Find the pH of a solution of 0.250 M HF and 0.200 M KF before and after dilution by a factor of 5. The pKa of HF is 3.20.
An equation analogous to the Henderson-Hasselbalch equation can be derived, which relates the pOH of the buffer to the pKb of the base component. Which of the following is the correct equation?
Calculate the concentrations of hydrofluoric acid and sodium fluoride in buffer solution with a pH of 3.57. The solution was measured to have freezing point of -5.50 °C and a density of 1.02 g/mL.
A student in an analytical chemistry laboratory needs to prepare a buffer of pH 5.00. She chooses 2-methylpropanoic acid (pKa = 4.84) to prepare the buffer. She has access to 0.100 M 2-methylpropanoic solution and 0.120 M sodium 2-methylpropanoate solution. How much volume (in mL) of each solution does she require to prepare a total of 50.0 mL of her required buffer?
Given equal volumes of each mixture component, determine which of the following is the most basic (highest pH).
Determine the pH of a 0.500 L solution of 0.15 M lactic acid-0.25 M sodium lactate buffer before and after 0.0050 mol NaOH is added. Assume the volume of X is negligible. The pKa of lactic acid is 3.86.
Consider a 250.0 mL of a buffer solution that is 0.396 M in CH3NH2 and 0.178 M in CH3NH3Br
Calculate initial and final pH after adding 0.0250 mol of KOH.
Find the pH of a 2.00 L solution of 0.110 M HNO2 and 0.110 M NaNO2 upon the addition of 150.0 mL of 0.225 M HBr. Note that the pKa of HNO2 is 3.25.
Consider a 250.0 mL buffer solution that is 0.125 M of HF and 0.175 M of NaF. Calculate [HF] and [NaF] after the addition of 2.56 g HCl.
A 100 mL buffer solution is 0.200 M in CH3COOH and 0.200 M in NaCH3COO. What will the pH of the solution be if 20 mL of 0.220 M HNO3 are added to this buffer? Ka of acetic acid = 1.78×10-5.
Hypochlorous acid, HClO is an oxyacid of chlorine. It is a weak acid with a dissociation constant (Ka) value of 3.98×10-8.
HClO(aq) ⇌ H+(aq) + ClO-(aq)
A) Calculate the pH of a buffer solution that contains 0.150 M hypochlorous acid with 0.250 M hypochlorite ion (ClO-).
B) What will the final pH of the solution be if 5.00 mL of 0.100 M HCl solution are added to 50.0 mL of this buffer?