Carbonate buffers help to regulate blood pH at a normal value of 7.40. Find the bicarbonate concentration needed to buffer blood pH if the carbonic acid concentration is assumed to be 0.0012 M. H2CO3 <--> HCO3- + H+  Ka = 4.3 x 10-7

4) Calculate how much you need to take from each solution to prepare 1 L of buffer solution with a pH value of 9.45 using 0.3 M Na2CO3 and 0.2 M HCl. (Ka1 = 4.3 × 10-7, Ka2 = 4.69x10-11)

Calculate the pH of a mixture of 10.00 mL of 0.250 M NH3 and 25.00 mL of 0.100 M HCl

What is the pH of the solution that results from mixing 25 mL of 2.20×10-2 M NH3 and 25 mL of 2.20×10-2 M HCl? Ka (NH4+) = 5.60×10-10 pH =

Design a buffer that has a pH of 6.70 using one of the weak acid/conjugate base systems shown below. Weak Acid Conjugate Base Ką pKa HC,04 C,0,²- 6.4 x 10-5 4.19 H,PO4 HPO,2- 6.2 x 10-8 7.21 HCO3 co,?- 4.8 × 10-11| 10.32 How many grams of the potassium salt of the weak acid must be combined with how many grams of the potassium salt of its conjugate base, to produce 1.00 L of a buffer that is 1.00 M in the weak base? grams potassium salt of weak acid = grams potassium salt of conjugate base =

Calculate the final [Ag1+] concentration in solution when 0.035 moles of AgNO3 are added to 500. mL of 0.21 M NaCN. Assume the volume remains constant. Ksp = 1.2 ✕ 10-16 for AgCN. (in M)

45.0 mL of a buffer solution contains 0.20 M CH3COOH and 0.25 M CH3COONa. What is the pH of the mixture after 18.0 mL of 0.45 M HCI is added to this buffer solution? Ka of CH3COOH = 1.8 x 10-5.

Which is true about buffer solutions? -they hold the pH close to the pKa  -they contain comparable moles of a weak acid and a strong base  - they hold pH constant at pH=7  -they prevent acids and bases from reaching equilibrium  -they hold the pH close to the equivalence point pH

for each of the five solutions calculate the equilibrium [H+] from the measured pH and determine the Kavalue. 1. pH = 2.34 // derived form 30.0 mL sample of 1.0 M HOAc 2. pH = 3.21 // derived form 30.0 mL sample of 0.1 M HOAc 3. pH = 4.88 // derived from adding 24.0 mL of 1.0 M NaOAc to 10.0 mL of 1.0 M HOAc 4. pH = 4.99 // derived from diluting 10 mL of solution 3 with 40.0 mL deionized water 5. pH = 9.33 // derived form 30.0 mL sample of 1.0 M NaOAc

Assuming equal concentrations of conjugate base and acid, which one of the following mixtures is the best choice for making a buffer solution with an optimum pH in the range of 3.1-3.5? O O O NaNO2/HNO2 (K₂ = 4.6 x 10-4) KCH3COO/CH3COOH (K₂ = 1.75 x 10-5) CH3NH2/CH3NH3CI (K₂ = 2.3 x 10-11) NaOCN/HOCN (K₂ = 2.0 x 10-4) NaNO3/HNO3 20