Calculate the pH of 0.300 M piperazine. Calculate the concentration of each form of

Find the pH and the concentrations of H2SO3,

(a) How many grams of NaHCO3 (FM 84.007) must be added to 4.00 g of K2CO3 (FM 138.206) to give a pH of 10.80 in 500 mL of water?

How many milliliters of 0.800 M KOH should be added to 5.02 g of 1,5-pentanedioic acid (C5H8O4, FM 132.11) to give a pH of 4.40 when diluted to 250 mL?

Calculate the pH of a 0.010 M solution of each amino acid in the form drawn here. (a) (b) (c) Glutamine Cysteine Arginine H2NCHCO2 CH2 CH2 NH H2N NH2 CH2 C H3NCHCO2 S CH2 O H3NCHCO2 CH2 CH2 NH2 C

(a) Draw the structure of the predominant form (principal species) of 1,3-dihydroxybenzene at pH 9.00 and at pH 11.00. (b) What is the second most prominent species at each pH? (c) Calculate the percentage in the major form at each pH.

Draw the structures of the predominant forms of glutamic acid and tyrosine at pH 9.0 and pH 10.0. What is the second most abundant species at each pH?

Calculate the isoionic pH of 0.010 M lysine.

Neutral lysine can be written HL. The other forms of lysine are H3L2, H2L, and L. The isoelectric point is the pH at which the average charge of lysine is 0. Therefore, at the isoelectric point, 2[H3L2] [H2L] = [L]. Use this condition to calculate the isoelectric pH of lysine. Diprot

Consider HA, the intermediate form of a diprotic acid. Ka for this species is 104 and Kb is 108 . Nonetheless, the Ka and Kb reactions proceed to nearly the same extent when NaHA is dissolved in water. Explain. 9-

Write the general structure of an amino acid. Why do some amino acids in Table 9-1 have two pK values and others three?

Write the chemical reactions whose equilibrium constants are Kb1 and Kb2 for the amino acid proline. Find the values of Kb1 and Kb2.

Consider the diprotic acid H2A with K1  1.00  104 and K2  1.00  108 . Find the pH and concentrations of H2A, HA, and A2 in (a) 0.100 M H2A; (b) 0.100 M NaHA; (c) 0.100 M Na2A. 9-5.

We will abbreviate malonic acid, \(\mathrm{CH}_{2}\left(\mathrm{CO}_{2} \mathrm{H}\right)_{2}\), as \(\mathrm{H}_{2} \mathrm{M}\). Find the \(\mathrm{pH}\) and concentrations of \(\mathrm{H}_{2} \mathrm{M}, \mathrm{HM}^{-}\), and \(\mathrm{M}^{2-}\) in (a) \(0.100 \mathrm{M}\) \(\mathrm{H}_{2} \mathrm{M}\); (b) \(0.100 \mathrm{M} \mathrm{NaHM}\); (c) \(0.100 \mathrm{M} \mathrm{Na}_{2} \mathrm{M}\).

Calculate the pH of 0.300 M piperazine. Calculate the concentration of each form of piperazine in this solution.

Use the method of Box 9-2 to calculate the concentrations of H, H2A, HA, and A2 in 0.001 00 M monosodium oxalate, NaHA. 9

Activity. In this problem, we calculate the pH of the intermediate form of a diprotic acid, taking activities into account. (a) Including activity coefficients, derive Equation 9-11 for potassium hydrogen phthalate (KHP in the example following Equation 9-12). (b) Calculate the pH of 0.050 M KHP, using the results in part (a). Assume that the sizes of both HP and P2 are 600 pm. 9-9

Intermediate form of diprotic acid. Use the method in Box 9-2 to find the pH and concentration of HA in a 0.01 F solution of the amphiprotic salt NaHA derived from the diprotic acid H2A with pK1  4 and (a) pK2  8 or (b) pK2  5. 9-

Derivation of Equation 9-10 for pH of the intermediate form NaHA. The derivation in the chapter was for HL, the intermediate form of H2L. Write the mass and charge balances for NaHA at formal concentration F. Substitute [H2A] [HA] [A2] for [Na] in the charge balance. After canceling like terms on both sides of the charge balance, express all concentrations in terms of [HA] and [H]. Solve for [H] and show that you end up with the same expression as Equation 9-10. 9-11. Hetero

Heterogeneous equilibrium. CO2 dissolves in water to give carbonic acid (which is mostly dissolved CO2, as described in Box 6-4). (The equilibrium constant is called the Henrys law constant for carbon dioxide, because Henrys law states that the solubility of a gas in a liquid is proportional to the pressure of the gas.) The acid dissociation constants listed for carbonic acid in Appendix G apply to CO2(aq). Given that in the atmosphere is 103.4 atm, find the pH of water in equilibrium with the atmosphere.

(a) Combine the expressions for KH, Ka1, and Ka2 to find an expression for [CO3 2] in terms of and [H]. (b) From the result of (a), calculate [CO3 2] (mol kg1 ) at PCO2  800 bar and pH  7.8 at temperatures of 0 (polar ocean) and 30C (tropical ocean). These are conditions that could be reached around the year 2100 if we continue to release CO2 at the present rate. (c) The concentration of Ca2 in the ocean is 0.010 M. Predict whether aragonite and calcite will dissolve under the conditions in (b). Dip

How many grams of Na2CO3 (FM 105.99) should be mixed with 5.00 g of NaHCO3 (FM 84.01) to produce 100 mL of buffer with pH 10.00?

How many milliliters of 0.202 M NaOH should be added to 25.0 mL of 0.023 3 M salicylic acid (2-hydroxybenzoic acid) to adjust the pH to 3.50?

Describe how you would prepare exactly 100 mL of 0.100 M picolinate buffer, pH 5.50. Possible starting materials are pure picolinic acid (pyridine-2-carboxylic acid, FM 123.11), 1.0 M HCl, and 1.0 M NaOH. Approximately how many milliliters of the HCl or NaOH will be required?

How many grams of Na2SO4 (FM 142.04) should be added to how many grams of sulfuric acid (FM 98.08) to give 1.00 L of buffer with pH 2.80 and a total sulfur ( SO4 2 HSO4 H2SO4) concentration of 0.200 M? Pol

Phosphate at 0.01 M is one of the main buffers in blood plasma, whose pH is 7.45. Would phosphate be as useful if the plasma pH were 8.5?

Starting with the fully protonated species, write the stepwise acid dissociation reactions of the amino acids glutamic acid and tyrosine. Be sure to remove the protons in the correct order. Which species are the neutral molecules that we call glutamic acid and tyrosine?

(a) Calculate the quotient [H3PO4]/[H2PO4 ] in 0.050 0 M KH2PO4. (b) Find the same quotient for 0.050 0 M K2HPO4.

(a) Which two of the following compounds would you mix to make a buffer of pH 7.45: H3PO4 (FM 98.00), NaH2PO4 (FM 119.98), Na2HPO4 (FM 141.96), and Na3PO4 (FM 163.94)? (b) If you wanted to prepare 1.00 L of buffer with a total phosphate concentration of 0.050 0 M, how many grams of each of the two selected compounds would you mix together? (c) If you did what you calculated in part (b), you would not get a pH of exactly 7.45. Explain how you would really prepare this buffer in the lab.

Find the pH and the concentration of each species of lysine in a solution of 0.010 0 M lysine HCl, lysine monohydrochloride.

How many milliliters of 1.00 M KOH should be added to 100 mL of solution containing 10.0 g of histidine hydrochloride (His HCl, FM 191.62) to get a pH of 9.30?

(a) Using activity coefficients, calculate the pH of a solution containing a 2.00:1.00 mole ratio of HC2:C3 (H3C  citric acid). The ionic strength is 0.010 M. (b) What will be the pH if the ionic strength is raised to 0.10 M and the mole ratio HC2:C3 is kept constant? Whi

The acid HA has pKa  7.00. (a) Which is the principal species, HA or A, at pH 6.00? (b) Which is the principal species at pH 8.00? (c) What is the quotient [A]/[HA] at pH 7.00? at pH 6.00? 9

The diprotic acid H2A has pK1  4.00 and pK2  8.00. (a) At what pH is [H2A]  [HA]? (b) At what pH is [HA]  [A2]? (c) Which is the principal species at pH 2.00: H2A, HA, or A2? (d) Which is the principal species at pH 6.00? (e) Which is the principal species at pH 10.00? 9-26

The base B has pKb  5.00. (a) What is the value of pKa for the acid BH? (b) At what pH is [BH]  [B]? (c) Which is the principal species at pH 7.00: B or BH? (d) What is the quotient [B]/[BH] at pH 12.00? 9-2

Draw the structure of the predominant form of pyridoxal-5- phosphate at pH 7.00.

The acid HA has pKa  4.00. Use Equations 9-17 and 9-18 to find the fraction in the form HA and the fraction in the form A at pH  5.00. Does your answer agree with what you expect for the quotient [A]/[HA] at pH 5.00? 9

A dibasic compound, B, has pKb1  4.00 and pKb2  6.00. Find the fraction in the form BH2 2 at pH 7.00, using Equation 9-19. Note that K1 and K2 in Equation 9-19 are acid dissociation constants for BH2 2(K1  Kw/Kb2 and K2  Kw /Kb1). 9

A dibasic compound, B, has pKb1  4.00 and pKb2  6.00. Find the fraction in the form BH2 2 at pH 7.00, using Equation 9-19. Note that K1 and K2 in Equation 9-19 are acid dissociation constants for BH2 2(K1  Kw/Kb2 and K2  Kw /Kb1). 9

Calculate , , and for cis-butenedioic acid at pH 1.00, 1.92, 6.00, 6.27, and 10.00.

(a) Derive equations for , , and for a triprotic system. (b) Calculate the values of these fractions for phosphoric acid at pH 7.00.

A solution containing acetic acid, oxalic acid, ammonia, and pyridine has a pH of 9.00. What fraction of ammonia is not protonated?

A solution was prepared from 10.0 mL of 0.100 M cacodylic acid and 10.0 mL of 0.080 0 M NaOH. To this mixture was added 1.00 mL of 1.27  106 M morphine. Calling morphine B, calculate the fraction of morphine present in the form BH.

Fractional composition in a diprotic system. Create a spreadsheet with Equations 9-19 through 9-21 to compute the three curves in Figure 9-4. Plot the three curves in a beautifully labeled figure.

Fractional composition in a triprotic system. For a triprotic system, the fractional composition equations are A3  K1K2K3 D H2A  K1[H] 2 D HA2  K1K2[H] D H3A  [H] 3 D (C

Fractional composition in a tetraprotic system. Prepare a fractional composition diagram analogous to Figure 9-4 for the tetraprotic system derived from hydrolysis of Cr3: (Yes, the values of Ka2 and Ka3 are equal.) (a) Use these equilibrium constants to prepare a fractional composition diagram for this tetraprotic system. (b) You should do this part with your head and your calculator, not your spreadsheet. The solubility of Cr(OH)3 is given by What concentration of Cr(OH)3(aq) is in equilibrium with solid Cr(OH)3(s)? (c) What concentration of Cr(OH)2 is in equilibrium with Cr(OH)3(s) if the solution pH is adjusted to 4.00? I

What is the difference between the isoelectric pH and the isoionic pH of a protein with many different acidic and basic substituents?

Explain what is wrong with the following statement: At its isoelectric point, the charge on all molecules of a particular protein is 0.

Calculate the isoelectric and isoionic pH of 0.010 M threonine.

Explain how isoelectric focusing works.