Calculate the pH of a solution containing 0.53 mol of H2PO4 and 3.3 mol H2PO4-2. The Ka of H2PO4 - is 6.2\times 10-8. A. 7.1 B. 4.6 C. 6.8 D. 7.0 E. 5.7

For the following, mix equal volumes of one solution from Group I with one solution from Group II to achieve the indicated pH. Calculate the pH of each solution. Group I: 0.20 M NH4Cl, 0.20 M HCl, 0.20 M C6H5NH3Cl, 0.20 M (C2H5)3NHCl Group II: 0.20 M KOI, 0.20 M NaCN, 0.20 M KOCl, 0.20 M NaNO2 a. the solution with the lowest pH b. the solution with the highest pH c. the solution with the pH closest to 7.00

A solution is made by dissolving 15.0 g sodium hydroxide in approximately 450 mL water. The solution becomes quite warm, but after it is allowed to return to room temperature, water is added to bring the volume to 500.0 mL of solution. (a) Calculate the pH and pOH in the final solution. (b) Why would we wait for it to return to room temperature? (c) If the mass of the water used to initially dissolve the sodium hydroxide were exactly 450 g and the temperature of the water increased by 8.865 C, how much heat was given off by the dissolution of 15.0 g of solute? Assume the specific heat of the solution is 4.184 J/g. K. What is the molar heat change for the dissolution of sodium hydroxide (known as the enthalpy of solution, Hsol)?

The pH of a 0.10-M solution of caffeine is 11.16. Determine Kb for caffeine from these data: C8H10N4O2(aq)+H2O(l)C8H10N4O2H+(aq)+OH(aq)