1. What colour would 1.0 M HCl be in an indicator mixture consisting of phenol red and

Transcription

1 cids Practice Test 2 1. What colour would 1.0 M Hl be in an indicator mixture consisting of phenol red and thymolphthalein? red blue yellow colourless 2. uring a titration, what volume of M KOH is necessary to completely neutralize 10.0 ml of 2.00 M H 3 OOH? 10.0 ml 20.0 ml 25.0 ml 40.0 ml 3. Which indicator has a Ka = 1.0 x 10 6? neutral red thymol blue thymolpthalein chlorophenol red 4. cid is added to a buffer solution. When equilibrium is reestablished the buffering effect has resulted in [H 3 O + ] increasing slightly decreasing slightly increasing considerably decreasing considerably 5. buffer solution will form when 0.10 M NaF is mixed with an equal volume of 0.10 M HF 0.10 M Hl 0.10 M Nal 0.10 M NaOH

2 6. Which of the following statements applies to 1.0 M NH 3(aq) but not to 1.0 M NaOH (aq)? partially ionizes neutralizes an acid has a ph greater than 7 turns bromocresol green from yellow to blue 7. In which of the following are the reactants favoured? HNO 2 + N NO 2 H 2 S + HO 3 + HN HS + H 2 O 3 H 3 PO 4 + NH 3 H 2 PO 4 H 3 OOH + PO NH 4 + H 3 OO + HPO What is the poh of a solution prepared by adding 0.50 moles of NaOH to prepare 0.50 L of solution? What is the [H 3 O + ] in a solution with a ph = 5.20? 1.4 x x x x onsider the following equilibrium: 2H 2 O (l) + energy H 3 O + (aq) + OH (aq) What will cause the ph to increase and the Kw to decrease? adding a strong acid adding a strong base increasing the temperature decreasing the temperature 11. The complete neutralization of 15.0 ml of KOH requires moles H 2 SO 4. The [KOH] was 1.50 M 1.67 M 3.33 M 6.67 M

3 12. What is the [H 3 O + ] at the equivalence point for the titration between Hr and KOH? 1.0 x 10 9 M 1.0 x 10 7 M 1.0 x 10 5 M 0.0 M 13. Which of the following would form a buffer solution when equal moles are mixed together? Hl and Nal HN and NaN KNO 3 and KOH Na 2 SO 4 and NaOH 14. Which of the following acids has the weakest conjugate base? HIO 3 HNO 2 H 3 PO 4 H 3 OOH 15. When 10.0 ml of 0.10 M Hl is added to 10.0 ml of water, the concentration of H 3 O + in the final solution is M M 0.10 M 0.20 M 16. The conjugate base of an acid is produced by adding a proton to the acid adding an electron to the acid removing a proton from the acid removing an electron from the acid 17. Which of the following represents the predominant reaction between HO 3 and water? 2HO 3 H 2 O + 2O 2 HO 3 + H 2 O H 2 O 3 + OH HO 3 + H 2 O H 3 O O 3 2HO 3 + H 2 O H 3 O O 3 + OH + O 2

4 18. Water acts as an acid when it reacts with I N II NH 3 III HlO 4 IV H 3 OO I and IV only II and III only I, II, and IV II, III, and IV 19. In a solution of 0.10 M H 2 SO 4, the ions present in order of decreasing concentration are [H 3 O + ] > [HSO 4 ] > [SO 4 2 ] > [OH ] [H 3 O + ] > [SO 4 2 ] > [HSO 4 ] > [OH ] [OH ] > [SO 4 2 ] > [HSO 4 ] > [H 3 O + ] [SO 4 2 ] > [HSO 4 ] > [OH ] > [H 3 O + ] 20. Which of the following will dissolve in water to produce an acidic solution? O 2 ao MgO Na 2 O 21. Which of the following solutions will have a ph = 1.00? I 0.10 M Hl II 0.10 M HNO 2 III 0.10 M NaOH I only II only I and II only I, II, and III 22. Ka for the acid H 2 so 4 is 5.6 x What is the value of the Kb for HsO 4 2? 5.6 x x x x In a titration, which of the following has a ph = 7.00 at the equivalence point? NH 3 and HNO 3 KOH and Hl NaF and Hl a(oh) 2 and H 3 OOH

5 24. Which of the following salts dissolves to produce a basic solution? Kl NH 4 r Fe(NO 3 ) 3 LiH 3 OO 25. alculate the ph in a M solution of Sr(OH) Which of the following solutions has a ph less than 7.00? Nal LiOH NH 4 NO 3 KH 3 OO 27. Which of the following will form a basic aqueous solution? HSO 3 HSO 4 HPO 4 2 H 2 O What is the approximate Ka value for the indicator chlorophenol red? 1 x x x x What is the approximate ph of the solution formed when mol NaOH is added to 2.00 L of M Hl?

6 30. In which one of the following equations are the ronsted acids and bases all correctly identified? cid + ase ase + cid H 2 O 2 2 SO 3 HO 2 H 2 O 2 2 SO 3 HSO 3 2 SO 3 H 2 O 2 HO 2 2 SO 3 H 2 O 2 HSO 3 HSO 3 HO 2 HSO 3 HO Which of the following titrations will always have an equivalence point at a ph > 7.00? weak acid with a weak base strong acid with a weak base weak acid with a strong base strong acid with a strong base 32. buffer solution may contain equal moles of weak acid and strong base strong acid and strong base weak acid and its conjugate base strong acid and its conjugate base 33. gas which is produced by burning coal and also contributes to the formation of acid rain is H 2 O 3 SO 2 3 H Which of the following 1.0 M salt solutions is acidic? as NH 4 l a(no 3 ) 2 NaH 3 OO 35. Which of the following statements applies to 1.0 M NH 3(aq) but not to 1.0 M NaOH(aq)? partially ionizes neutralizes and acid has a ph greater than 7 turns bromcresol green from yellow to blue

7 36. When the indicator thymol blue is added to 0.10 M solution of an unknown acid, the solution is red. The acid could be HF H 2 S HN HNO 3 Subjective 1. alculate the ph of the solution prepared by mixing 15.0 ml of 0.50 M Hl with 35.0 ml 0.50 M NaOH. 2. alculate the [OH ] in 0.50 M NH 3(aq). 3. titration was performed by adding M H 2 2 O 4 to a ml sample of NaOH. The following data was collected. Trial 1 Trial 2 Trial 3 Final volume of H 2 2 O 4 from burette (ml) Initial volume of H 2 2 O 4 from burette (ml) alculate the [NaOH] ml sample of Hl with a ph of is completely neutralized with M NaOH. What volume of NaOH is required to reach the stoichiometric point. 5. If the Hl were titrated with M NH 3(aq) instead of M NaOH, how would the volume of base required to reach the equivalence point compare with the volume calculated in the last question? Explain your answer. 6. onsider the following salt ammonium acetate, NH 4 H 3 OO. a) Write the equation for the dissociation of NH 4 H 3 OO. b) Write the equations for the hydrolysis reactions that occur. c) Explain why a solution of NH 4 H 3 OO has a ph =7.00. Support your answer with a calculation. 7. onsider the following equilibrium: energy + 2H 2 O H 3 O + + OH a) Explain how pure water can have a ph = b) alculate the value of the Kw for the sample of water with a ph = 7.30.

8 cids Practice Test 2 1. What colour would 1.0 M Hl be in an indicator mixture consisting of phenol red and thymolphthalein? red blue yellow colourless 2. uring a titration, what volume of M KOH is necessary to completely neutralize 10.0 ml of 2.00 M H 3 OOH? 10.0 ml 20.0 ml 25.0 ml 40.0 ml 3. Which indicator has a Ka = 1.0 x 10 6? neutral red thymol blue thymolpthalein chlorophenol red 4. cid is added to a buffer solution. When equilibrium is reestablished the buffering effect has resulted in [H 3 O + ] increasing slightly decreasing slightly increasing considerably decreasing considerably 5. buffer solution will form when 0.10 M NaF is mixed with an equal volume of 0.10 M HF 0.10 M Hl 0.10 M Nal 0.10 M NaOH

9 6. Which of the following statements applies to 1.0 M NH 3(aq) but not to 1.0 M NaOH (aq)? partially ionizes neutralizes an acid has a ph greater than 7 turns bromocresol green from yellow to blue 7. In which of the following are the reactants favoured? HNO 2 + N NO 2 + HN H 2 S + HO 3 HS + H 2 O 3 + H 3 PO 4 + NH 3 H 2 PO 4 + NH 4 H 3 OOH + PO 4 3 H 3 OO + HPO What is the poh of a solution prepared by adding 0.50 moles of NaOH to prepare 0.50 L of solution? What is the [H 3 O + ] in a solution with a ph = 5.20? 1.4 x x x x onsider the following equilibrium: 2H 2 O (l) + energy H 3 O + (aq) + OH (aq) What will cause the ph to increase and the Kw to decrease? adding a strong acid adding a strong base increasing the temperature decreasing the temperature 11. The complete neutralization of 15.0 ml of KOH requires moles H 2 SO 4. The [KOH] was 1.50 M 1.67 M 3.33 M 6.67 M 12. What is the [H 3 O + ] at the equivalence point for the titration between Hr and KOH? 1.0 x 10 9 M 1.0 x 10 7 M

10 1.0 x 10 5 M 0.0 M 13. Which of the following would form a buffer solution when equal moles are mixed together? Hl and Nal HN and NaN KNO 3 and KOH Na 2 SO 4 and NaOH 14. Which of the following acids has the weakest conjugate base? HIO 3 HNO 2 H 3 PO 4 H 3 OOH 15. When 10.0 ml of 0.10 M Hl is added to 10.0 ml of water, the concentration of H 3 O + in the final solution is M M 0.10 M 0.20 M 16. The conjugate base of an acid is produced by adding a proton to the acid adding an electron to the acid removing a proton from the acid removing an electron from the acid 17. Which of the following represents the predominant reaction between HO 3 and water? 2HO 3 H 2 O + 2O 2 HO 3 + H 2 O H 2 O 3 + OH HO 3 + H 2 O H 3 O O 3 2HO 3 + H 2 O H 3 O O 3 + OH + O Water acts as an acid when it reacts with I N II NH 3 III HlO 4 IV H 3 OO I and IV only II and III only

11 I, II, and IV II, III, and IV 19. In a solution of 0.10 M H 2 SO 4, the ions present in order of decreasing concentration are [H 3 O + ] > [HSO 4 ] > [SO 4 2 ] > [OH ] [H 3 O + ] > [SO 4 2 ] > [HSO 4 ] > [OH ] [OH ] > [SO 4 2 ] > [HSO 4 ] > [H 3 O + ] [SO 4 2 ] > [HSO 4 ] > [OH ] > [H 3 O + ] 20. Which of the following will dissolve in water to produce an acidic solution? O 2 ao MgO Na 2 O 21. Which of the following solutions will have a ph = 1.00? I 0.10 M Hl II 0.10 M HNO 2 III 0.10 M NaOH I only II only I and II only I, II, and III 22. Ka for the acid H 2 so 4 is 5.6 x What is the value of the Kb for HsO 4 2? 5.6 x x x x In a titration, which of the following has a ph = 7.00 at the equivalence point? NH 3 and HNO 3 KOH and Hl NaF and Hl a(oh) 2 and H 3 OOH 24. Which of the following salts dissolves to produce a basic solution? Kl NH 4 r Fe(NO 3 ) 3 LiH 3 OO

12 25. alculate the ph in a M solution of Sr(OH) Which of the following solutions has a ph less than 7.00? Nal LiOH NH 4 NO 3 KH 3 OO 27. Which of the following will form a basic aqueous solution? HSO 3 HSO 4 HPO 4 2 H 2 O What is the approximate Ka value for the indicator chlorophenol red? 1 x x x x What is the approximate ph of the solution formed when mol NaOH is added to 2.00 L of M Hl? In which one of the following equations are the ronsted acids and bases all correctly identified? cid + ase ase + cid H 2 O 2 + SO 3 2 H 2 O 2 + SO 3 2 HO 2 + HSO 3 HSO 3 + HO 2

13 SO 3 2 SO H 2 O 2 HO 2 + H 2 O 2 HSO 3 + HSO 3 + HO Which of the following titrations will always have an equivalence point at a ph > 7.00? weak acid with a weak base strong acid with a weak base weak acid with a strong base strong acid with a strong base 32. buffer solution may contain equal moles of weak acid and strong base strong acid and strong base weak acid and its conjugate base strong acid and its conjugate base 33. gas which is produced by burning coal and also contributes to the formation of acid rain is H 2 O 3 SO 2 3 H Which of the following 1.0 M salt solutions is acidic? as NH 4 l a(no 3 ) 2 NaH 3 OO 35. Which of the following statements applies to 1.0 M NH 3(aq) but not to 1.0 M NaOH(aq)? partially ionizes neutralizes and acid has a ph greater than 7 turns bromcresol green from yellow to blue 36. When the indicator thymol blue is added to 0.10 M solution of an unknown acid, the solution is red. The acid could be HF H 2 S HN HNO 3

14 Subjective 1. alculate the ph of the solution prepared by mixing 15.0 ml of 0.50 M Hl with 35.0 ml 0.50 M NaOH. Hl + NaOH Nal + HOH L x 0.50 moles L x 0.50 moles L L I moles moles moles moles E moles [OH ] = moles = 0.20M L poh = 0.70 ph = alculate the [OH ] in 0.50 M NH 3(aq). NH 3 + H 2 O NH OH I x x x Kb(NH 3 ) = 1.0 x Ka(NH + 4 ) E 0.50 x x x = 0 small Ka approximation Kb = 1.0 x x x x 2 = x 10 5

15 0.50 x = [OH] = 3.0 x 10 3 M 3. titration was performed by adding M H 2 2 O 4 to a ml sample of NaOH. The following data was collected. Trial 1 Trial 2 Trial 3 Final volume of H 2 2 O 4 from burette (ml) Initial volume of H 2 2 O 4 from burette (ml) average to ml alculate the [NaOH] reject H 2 2 O 4 + 2NaOH Na 2 2 O 4 + 2H L L M? M [NaOH] = L H 2 2 O 4 x mole x 2 mole NaOH L 1 mole H 2 2 O L = M ml sample of Hl with a ph of is completely neutralized with M NaOH. What volume of NaOH is required to reach the stoichiometric point. ph = [H + ] = M Hl + NaOH Nal + H 2 O L x mole x 1moleNaOH x L = L L 1 mole Hl mole

16 5. If the Hl were titrated with M NH 3(aq) instead of M NaOH, how would the volume of base required to reach the equivalence point compare with the volume calculated in the last question? Explain your answer. It would be the same Hl forces the reaction to completion so a weak base is as good as a strong base for neutralizing a strong acid. 6. onsider the following salt ammonium acetate, NH 4 H 3 OO. a) Write the equation for the dissociation of NH 4 H 3 OO NH H 3 OO b) Write the equations for the hydrolysis reactions that occur. H 3 OO + H 2 O H 3 OOH + OH NH H 2 O NH 3 + OH c) Explain why a solution of NH 4 H 3 OO has a ph =7.00. Support your answer with a calculation. Ka(NH 4 + ) = 5.6 x Kb(H 3 OO ) = Kw = 5.6 x 10 10