1. What is the pH of a buffer that contains 1.100 M NH3 and 1.300 M NH4+? Ka= 5.70x10-10 What would be the new pH if a 100 mL portion of 0.075 M HCl is added to another 400 mL portion of the buffer? 2. If a multivitamin was manufactured on March 2021, when is its most likely expiration date? a. June 2021 b.December 2021 c. September 2021 d. March 2022

1. What is the pH of a buffer that contains 1.100 M NH3 and 1.300 M NH4+? Ka= 5.70x10-10 What would be the new pH if a 100 mL portion of 0.075 M HCl is added to another 400 mL portion of the buffer? 2. If a multivitamin was manufactured on March 2021, when is its most likely expiration date? a. June 2021 b.December 2021 c. September 2021 d. March 2022

Chemistry

10th Edition

ISBN:9781305957404

Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Chapter15: Acid-base Equilibria

Section: Chapter Questions

Problem 20Q: Consider the following two acids: pKa1 = 2.98; pKa2 = 13.40 HO2CCH2CH2CH2CH2CO2H Adipic acid pKa1 =...

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Consider the following two acids: pKa1 = 2.98; pKa2 = 13.40 HO2CCH2CH2CH2CH2CO2H Adipic acid pKa1 = 4.41; pKa2 = 5.28 In two separate experiments the pH was measured during the titration of 5.00 mmol of each acid with 0.200 M NaOH. Each experiment showed only one stoichiometric point when the data were plotted. In one experiment the stoichiometric point was at 25.00 mL added NaOH, and in the other experiment the stoichiometric point was at 50.00 mL NaOH. Explain these results.
A 25.0025.00 mL solution of 0.033000.03300 M Na2CO3Na2CO3 is titrated with 0.026300.02630 M Ba(NO3)2Ba(NO3)2. Calculate pBa2+pBa2+ following the addition of the given volumes of Ba(NO3)2Ba(NO3)2. The KspKsp for BaCO3BaCO3 is 5.0×10−95.0×10−9.
I would need help with these questions step by step: Calculate the isoelectric and isoionic pH of 0.010 M threonine? pK1 = 2.15, pK2 = 9.12 Find the pH of a 1.00 L aqueous solution containing 12.43 g of tris (FM 121.14) plus 4.67 g of tris hydrochloride ( FM 157.60) ? What would be the new pH after adding 12.0 mL of 1.00 M NaOH to this buffer?
The titration on the right was performed by placing 10.00 mL solution in an Erlenmeyer flask and titrating it with 0.1000 M HCl. What are the pKa values of the species being titrated? 2.0 and 7.7 7.6 and 11.9 6.4 and 20.0 5.0 and 10.0 2.1 and 6.4 6.3 and 12.0
A 0.735 g sample of wheat flour was analyzed by the Kjeldahl method. The ammonia formed by addition of concentrated base after digestion with H2SO4 was distilled into 50 mL of 0.10 M HCl. The excess HCl was then back titrated with 22.3 mL of 0.15 M NaOH. Calculate the percent protein in the wheat flour sample (6.25 g of cereal protein for every g of N).
A 25.00 mL unknown water sample is titrated with a standardized 0.0140 M EDTA solution. It is determined that 8.54 mL of EDTA is required to reach the end point. The blank titre was determined to be 1.50 mL. Determine the concentration of Calcium in the water sample in ppm. (mwt. of CaCO3 = 100.0892 g/mol).
If to 100 ml of a solution of CH3COOH with a concentration of 0.0928 N. a) 200 ml of distilled water was added. Determine its new concentration expressed to 4 decimal places, and determine the pH of the final solution. Data: pKa = 4.756 at 25°C. Consider that degree of dissociation is very small. b) If it is mixed with 100 ml of a 0.0989 N CH3COONa solution. What is the pH of the buffer solution.
A 1.43 x 10-4 L solution of 45.7 mg/mL protein was analyzed using the Kjeldahl procedure. After digestion of the protein, the liberated NH3 was collected in 9.80 mL of 0235 M HCl. The unreacted acid required 10.75 mL of a standard solution of 0.0149 M NaOH for complete titration. Calculate the weight percent of nitrogen in the protein. (Molar mass N = 14.00674 g/mol)
For PbCl2, Ksp = 1.7 × 10−5 . What will occur if 250 mL of 0.12 M Pb(NO3)2 is mixed with 250 mL of 0.070 M NaCl?
The amount of calcium in physiologic fluids can be determined by a complexometric titration with EDTA. In one such analysis, a 0.100-mL sample of blood serum was made basic by adding 2 drops of NaOH and titrated with 0.00528 M EDTA, requiring 0.233 mL to reach the end point. Report the concentration of calcium in the sample as miligrams of Ca per 100 mL. (Ca = 40.078 amu).
2. Calculate the pH using Henderson-Hasselbalch equation of a 50mL buffer solution made from 0.20 M HC2H3O2 and 0.50 M C2H3O2- that has an acid dissociation constant, Ka for HC2H3O2 of 1.8 x 10-5. a.) What will be the change in pH of the buffer solution after the addition of 1.0 mL of 0.10N HCl b.) What is the total buffer capacity of the solution?
Your goal is to make a buffer with a pH of 4.75 from acetic acid and sodium acetate. Assume the pKa for acetic acid is 4.74. What is the volume of 1 M sodium acetate added to make your buffer? Report your answer to the tenths place. To do this, we use the Henderson-Hasselbach Equation pH = pkA + log (base/acid) where pkA = 4.74 for acetic acid, pH = target pH and [base] /[acid] = x/(1-x) since we don't know the concentration of the base, we will call it x the acid is just 1-x, assuming the two add up to 100% solve for x, and then you know the mL of base and acid to add.