AMAL KEBAJIKAN ( BUFFER, TITRATIONS & SOLUBILITY)

1. Identify which of the following mixed systems could function as a buffer solution. For each system that can function as a buffer, write the equilibrium equation for the conjugate acid/base pair in the buffer system;

i. KF/HF

ii. NH3/NH4Br

iii. KNO3/HNO3

iv. Na2CO3/NaHCO3

2. What is the pH of a buffer solution containing 0.500 M CH3COONa and 0.800 M CH3COOH? (Ka CH3COOH = 1.74 105)?

3. What is the pH of the solution obtained when 41g of CH3COONa is dissolved in 1L of 0.800 M CH3COOH (pKa CH3COOH = 4.76)?

4. What is the pH of the buffer solution obtained when 100 cm3 of 0.100M CH3COOH is mixed with 20cm3 of 0.300 M CH3COONa solution? The Ka for acetic acid is 1.7 x 10-5.

5. A buffer solution was made by dissolving 10.0 grams of CH3COONa in 200.0 mL of 1.00 M CH3COOH. Calculate the pH of the acetic acid/sodium acetate buffer solution. The Ka for acetic acid is 1.7 x 10-5.

6. 50.0 mL of 0.100 M HCl was added to a buffer consisting of 0.025 moles of CH3COONa and 0.030 moles of acetic acid. What is the pH of the buffer after the addition of the acid? Ka of acetic acid is 1.7 x 10-5.

7. Calculate the pH of a buffer which is 0.2 M with respect to ammonium sulphate and 0.1 M with respect to ammonia. (Ka of NH4+ = 5.6 x 10-10)

8. Methanoic acid, HCOOH, has a Ka value of 1.58 x 10-4 M. What ratio of methanoic acid and sodium methanoate would give a buffer of pH = 4?

9. What is the pH of a 1 L solution containing 0.240 mol HC2H3O2 and 0.180 mol NaC2H3O2? Ka(HC2H3O2) = 1.8 x 10-5

i. Calculate pH if 0.010 mol of HCl were added?

ii. Calculate pH if 0.010 mol of NaOH were added?

10. What would be the ratio of [conjugate base] to [conjugate acid] for a solution of citric acid, if the pH of the solution was 3.00. Would such a solution act as a buffer? Ka H3C6H5O7= 6.4 x 10-6

11. Calculate the pH of 0.12 moldm-3 ethanoic acid (Ka = 1.7 x 10-5).

i. Calculate the mass of sodium ethanoate (CH3COONa) which must be added to 500 cm3 this solution to give a buffer solution of pH = 4.60.

ii. Calculate the pH of this solution after 0.01 moles of HCl are added.

iii. Calculate the pH of this solution after 0.01 moles of NaOH are added.

12. Calculate the pH of a buffer solution which is 0.1 M with respect to HCN (Ka = 4.9 x 10-10) and 0.8 M with respect to sodium cyanide.

i. Calculate the pH after 0.05 moles of HCl are added to this buffer.

ii. Calculate the pH after 0.05 moles of NaOH are added to this buffer.

13. Suppose that you had a solution that was 0.165 M HOCl. Given that Ka = 3.0x10-8i. What is the pH of the solution?

ii. What would be the new value for the pH for the solution if 14.3 grams of Ca(OCl)2 was added to 1.0 L of the solution?

iii. Would the value of the [H3O+] increase, decrease or stay the same in the 0.165M HOCl solution if 0.74 grams of Ca(OH)2 was added to 1.0 L of the solution?

19. A buffer contains 0.20 M HCHO2 and 0.3 M NaCHO2. Volume of the solution is 125 mL. Ka HCHO2= 1.8 x 10-4.i. What is the ph of this buffer solutions?

ii. If 50.0 mL of 0.10 M NaOH added to the buffer solution, what is the pH?

iii. If 50.0 mL of 0.10 M NaOH added to the buffer solution, what is the pH?

14. What is the pH of a 1 L solution containing 0.240 mol HC2H3O2 and 0.180 mol NaC2H3O2? Ka(HC2H3O2) = 1.8 x 10-5.

i.What would be the pH if 0.010 mol of HCl were added to this buffer?

ii. What would be the pH if 0.010 mol NaOH were added to this buffer?

20. What is the pH of 50.00 mL buffer solution which is 2.00M in HC2H3O2 and 2.00M in NaC2H3O2

i. What is the new pH after 2.00 mL of 6.00M HCl is added to this buffer ?

ii. What is the new pH after 2.00 mL of 6.00M NaOH is added to this buffer?

15. Calculate the pH of a buffer solution which contains the weak monoprotic acid, propanoic acid (CH3CH2COOH), in concentration 0.1 M and sodium propanoate in concentration 0.05 M. Ka of propanoic acid is 1.26 x 10-5.

i. Calculate the pH of the solution after 0.01 moles of NaOH are added to 500 cm3 of the solution.

ii. Calculate the pH of the solution after 0.01 moles of HCl are added to 500 cm3 of the solution.

1. Write the solubility product expression for the following: a. PbI2(cr) Pb2+(aq) + 2I-(aq)b. Cu3(PO4)2(cr) 3Cu2+(aq) + 2PO43-2. The solubility product constant for silver iodide is 8.32 x 10-17. What is the silver ion concentration?

3. If [D+] is 2.00 x 10-5M at equilibrium, what is the Ksp for D2A?

4. What is the concentration of beryllium ions in a saturated solution of beryllium hydroxide? Ksp = 1.58 x 10-22

5. A saturated solution of lead iodide has a lead ion concentration of 1.21 x 10-3M. What is the Ksp for lead iodide?

6. What is the solubility (M) of AgBr if the Ksp is 5.0 x 10 -13?

7. If the solubility of Li2CO3 is 0.15M, what is its Ksp at this temperature?

8. What is the solubility (M) of PbI2 is the Ksp is 8.5 x 10-9?

9. If the solubility of Ag2CrO4 is 7.2 x 10-5M, what is the Ksp?

10. How many moles of AgCl will dissolve in 500.ml of water if the Ksp =0.7 x 10-10?

11. The solubility product constant for lead iodide is 7.08 x 10-9. What is the lead ion concentration?

12. If [Ag+] is 1.33 x 10-5M at equilibrium, what is the Ksp for AgCl?

13. What is the concentration of aluminum ions in a saturated solution of aluminum hydroxide? Ksp = 1.26 x 10-33

14. A saturated solution of lead iodide has a lead ion concentration of 1.21 x 10-3M. What is the Ksp for lead iodide?

15. Find the Ksp of BaCl2 if 0.095 grams can be recovered from 1.0 liter of a saturated solution.

16. If the Ksp of CuCO3 is 1.7 x 10-7, how many grams could be recovered from 2.0 liters of a saturated solution?

17. You add 1.0 g of Na2CO3 is added to 1.0 liters of a saturated solution of barium carbonatecalculate the [Ba+2] when equilibrium is re-established.

18. You add 2.2 g Na2CO3 is added to 2.0 liters of a saturated solution of magnesium carbonatecalculate the [Mg+2] when equilibrium is re-established (Ksp for magnesium carbonate is 6.82 x 10-6)

19. If 1.00 liter of 0.0200M NaCl is added to 1.00 liter of 0.0100M AgNO3. Will a precipitate of AgCl form?

20. 0.0216 grams of silver nitrate is added to 1.0 liter of 2.0 x 10-3M Na2Cr2O7 solution. Does Ag2Cr2O7 precipitate form?