28. Answer the following questions to find the mass (g) of dipotassium phthalate must be added to 250 mL of 0.0250 M phthalic acid to give a buffer of pH 5.75? MW K2P = 242.32 g/mol Ka2 = [H30^+] [P^-] / [HP^-] = 3.91 x 10^-6 What is the amount of P^2- needed in the buffer? 164.92 mmol 82.46 mmol 53.88 mmol 27.49 mmol

Consider a buffer made by adding 132.8 g of NaC₇H₅O₂ to 300.0 mL of 2.35 M HC₇H₅O₂ (Ka = 6.3 x 10⁻⁵) a What is the pH of this buffer?     b What is the pH of the buffer after 0.750 mol of H⁺ have been added?     c What is the pH of the buffer after 0.250 mol of OH⁻ have been added?

You are given 60 mL of 0.50 M phosphate buffer, pH = 6.83, to test. The starting composition of the buffer, both in terms of the concentration and the molar quantity of the two major phosphate species, is: Concentration of HPO42−: 0.304 M Molar quantity of HPO42−: 18.2 mmol Concentration of H2PO4−: 0.196 M Molar quantity of H2PO4−: 11.8 mmol You add 1.7 mL of 1.00 M HCl to the buffer. Calculate the molar quantity of H3O+ added as HCl, and the final molar quantity of HPO42− and H2PO4− at equilibrium. H3O+ =     HPO42− =     H2PO4− =  What is the new HPO42−/H2PO4− ratio, and the new pH of the solution? The pKa of H2PO4− is 6.64. Use the Henderson-Hasselbalch equation to calculate the new pH. Now take a fresh 60 mL of the 0.50 M pH 6.83 buffer and add 3.7 mL of 1.00 M NaOH. Using steps similar to those above, calculate the new pH of the solution.

A buffer contains 0.175 moles C2H5NH3NO3 and 0.225 moles C2H5NH2 in 800.0 mL water. Kp (C2H5NH2) = 4.3 x 104 Express value to three decimal places. Determine the number of moles of base that can be added before the buffer capacity is exceeded. moles base F TOOLS x10

What is the pH of a 1.0 L buffer made with 0.300 mol of HF (Ka = 6.8 × 10⁻⁴) and 0.200 mol of NaF to which 0.150 mol of NaOH were added?

Calculate the pH of a buffer when 0.010 moles of NaOH is added to 100. mL solution that is 0.20 M sodium pentanoate (C HCOONa) and 0.20 M pentanoic acid (CH₂COOH). PK (CH₂ a COOH) = 4.82.

I NEED NUMBER 4 WITH THE CORRECT NUMBER OF SIG FIG IN NOTATION AND UNIT

How many grams of sodium hypochlorite, NaCIO, need to be added to 227 mL of a 0.185 M solution of hypochlorous acid, HCIO, to get a buffer with a pH of 7.92? The Ką for hypochlorous acid is 2.9 × 10-8.