Design a buffer that has a pH of 3.35 using one of the weak acid/conjugate base systems shown below. Weak Acid Conjugate Base Ka HC2O4 H2PO4 HCO3 C2042- 6.4×10-5 рка 4.19 HPO42- 6.2×10-8 7.21 CO32- 4.8×10-11 10.32 How many grams of the sodium salt of the weak acid must be combined with how many grams of the sodium salt of its conjugate base, to produce 1.00 L of a buffer that is 1.00 M in the weak base? grams sodium salt of weak acid = grams sodium salt of conjugate base = g مه g

What is a buffer?  Choose 2.   a solution that resists changes in pH a solution that neutralizes a basic solution a weak acid-base conjugate pair a solution that neutralizes an acidic solution a strong acid-base conjugate pair

What is the pH of a buffer that contains 0.356 M H2C6H606 and 0.647 М НС,Н,О6? Ka1 = 7.9 × 10-5 Ka2 = 1.6 x 10-12 IMPORTANT: When entering your answer: • Erter the number only (no units) • Do not leave any spaces • Use a leading zero before the decimal when necessary Report your number to 2 decimal places (regardless of the significant figures) • Correctly round your answer to the 2nd decimal place (allowed margin of error is only + 0.01, so always use un- rounded numbers in your calculations) Examples: 0.12 or 9.87

Pp

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 =

Which combination would be preferable to form a buffer? OWeak acid and its conjugate base Weak acid and its conjugate acid Strong acid and a strong base Weak acid and a weak base Strong acid and its conjugate base

Which of the following is not a characteristic of buffer solutions? O They cannot be tailored to maintain a specified pH. O They contain a conjugate base of a weak acid. O They contain a weak acid. O They have a finite capacity for accommodating added acid or base. O They can maintaln their pH, even when small amounts of acid or base are added. QUESTION 10 The capacity of a buffer solution is greater when there are large amounts of a weak acid and its conjugate base in solution. O True O False

Determine the Ka value Solution 1 3.98 X 10-3 M Solution 2 6.03 X 10-4 M Solution 3 1.07 X 10-5 M Solution 4  1.05 X 10-5 M Solution 5  4.68 X 10-10 M

Which of the following acid/base pairs would not make a good buffer system? H2PO4-/ HPO42- HSO3-/Na2SO3 H2CO3/H2CO2- NH4+/NH3 HNO2/NO2-