Calculate the pH of 0.005 0 M phenylacetic acid. The Ka for phenylacetic acid is 4.90 × 10–11. Hint: Solve the weak-acid equilibrium problem, ignoring the change in the formal concentration of phenylacetic acid.

Calculate the pH of a 0.033 M Na2SO3 solution. pK1 = 1.66 and pK2 = 6.85 for sulfurous acid.

___________ expresses the margin of uncertainty associated with a measurement.

Calculate the percent dissociation for a 0.010 0 M HCN solution. Ka = 6.2 × 10−10 for HCN. (Report at least 3 decimal places) Hint: Solve the weak-acid equilibrium for , ignoring the change in the formal concentration of HCN. Divide the concentration of the cyanide ion by the formal concentration and multiply by 100.

Which of the following compounds is NOT an aprotic solvent?

Calculate pPb2+ at the equivalence point when 25.00 mL of 0.120 M  is titrated with 0.120 M Pb2+. Ksp = 7.4 × 10−14 for PbCO3.

Calculate the pH of 0.005 0 M HF. The Ka for HF is 6.8 × 10−4.

Three different bottles of vinegar were analyzed by the same analyst for percentage acetic acid content. The following results were obtained. Bottle no.1 Bottle no. 2 Bottle no.3 3.88 8.13 3.92 8.19 3.75 8.17 3.84 8.05 3.91 8.21 How many measurements of sample 2 would have to be taken to reduce the 95% C.I. to 0.0200 ppm? (report 3 decimal places)

Calculate the pH of 0.050 0 M NaF. The Ka for HF is 6.8 × 10−4. (Report 2 decimal places) Hint: Determine Kb for F− from the Ka for HF. Solve the weak-base equilibrium problem for , ignoring the change in the formal concentration of F−. Calculate the pOH and then the pH.

Three different bottles of vinegar were analyzed by the same analyst for percentage acetic acid content. The following results were obtained. Bottle no.1 Bottle no. 2 Bottle no.3 3.88 5.72 3.92 5.61 3.75 5.60 3.84 5.68 3.91 5.66 How many measurements of sample 3 would have to be taken to reduce the 90% C.I. to 0.0750 ppm? (report 3 decimal places)