Consider a pH titration curve at 298 K for 50 mL of 0.10 M hypobromous acid, HBrO (Ka = 2.8 x 10−9), titrated with 0.10 M KOH solution. a. What volume of KOH is needed to reach the half-equivalence point? b. Calculate the pH of the HBrO sample at the half-equivalence point. c. Calculate the equivalence point pH.  d. Identify a satisfactory pH indicator for the equivalence point. The pH range of colour change is indicated in parentheses. A) Methyl orange (3.0 - 4.3)  B) Bromocresol purple (5.0 - 6.5)  C) Alizarin yellow R (10.0 - 12.0)  D) Methyl red (4.2 - 6.2)

Consider a buffer solution of acetate. The volume is 500 ml, the concentration is 200 mM, and the pH is 5.0. a. How many total moles of acetate plus acetic acid are present in the solution? Express answer as x.y with one digit before and one after the decimal place. b. What is the ratio of acetate ions (Ac-) to acetic acid ions (HAc) in the buffer solution (pH 5.0) if the pka is 4.76? Express the answer as x.yz with one digit before and two after the decimal place. c. How many moles of acetate are present in the solution? Express your answer to one decimal place. d. How many moles of acetic acid are present in the solution? Express your answer to one decimal place.

Consider a buffer solution that contains 0.55 M NH2CH2CO2H and 0.35 M NH2CH2CO2Na. pKa(NH2CH2CO2H)=9.88. a. Calculate its pH. b. Calculate the change in pH if 0.155 g of solid NaOH is added to 250 mL of this solution. c. If the acceptable buffer range of the solution is ±0.10 pH units, calculate how many moles of H3O+ can be neutralized by 250 mL of the initial buffer.

Consider a mixture of two proteins with molecular weights of 20,000 and 200,000. For simplicity of calculation, both may be approximated as unhydrated spheres with VB 0.740 mL g1. a. Calculate the ratio of the sedimentation coefficients of the proteins in the same medium (density=1.05 g mL¯1) at the same temperature.