Chem 110 Name Exam #5 May 2, 2017 Closed Book Exam - No books or notes allowed. All work must be shown for full credit. You may use a calculator. Question Credit TOTAL Multiple Choice 3 ⅓ points each. Before answering any of the questions, complete and balance the reaction. 1. How many moles of oxygen gas react with 0.100 mol of pentane, C 5 H 12? spark C 5 H 12 (g) + O 2 (g) CO 2 (g) + H 2 O(g) 0.100 mol 0.600 mol 0.800 mol 2. Considering the limiting reactant concept, how many moles of copper(i) sulfide are produced from the reaction of 1.00 mol of copper and 1.00 mol of sulfur? 2 Cu(s) + S(s) Cu 2 S(s) 1.00 mol 1.50 mol 2.00 mol 3. What is the mass of barium hydroxide (171.35 g/mol) dissolved in 0.500 L of 0.100 M Ba(OH) 2 solution? 8.57 g 17.1 g 85.7 g 171 g 857 g
4. Which of the following increases the rate of dissolving for a solid solute in a solvent? grinding the solute heating the solution stirring the solution all of the above 5. What is the mass of solute dissolved in 50.0 g of a 12.5% saline solution? 4.00 g 6.25 g 7.14 g 43.8 g 625 g 6. What is the molarity of a saline solution that contains 0.900 g NaCl (58.44 g/mol) dissolved in 100.0 ml of solution? 0.154 M 0.527 M 1.54 M 1.90 M 5.27 M 7. What is the mass of barium hydroxide (171.35 g/mol) dissolved in 0.500 L of 0.100 M Ba(OH) 2 solution? 8.57 g 17.1 g 85.7 g 171 g 857 g 8. What is the molarity of an acetic acid solution prepared by diluting 200.0 ml of 0.500 M HC 2 H 3 O 2 to a total volume of 1.00 L? 0.100 M 0.200 M 0.250 M 1.00 M 2.50 M
9. What volume of 18 M sulfuric acid must be diluted with distilled water to prepare 500.0 ml of 0.50 M H 2 SO 4? 0.014 ml 0.14 ml 1.4 ml 14 ml 140 ml 10. What volume of 0.100 M sulfuric acid reacts completely with 0.500 g of sodium hydrogen carbonate, NaHCO 3 (84.01 g/mol)? 2 NaHCO 3 (s) + H 2 SO 4 (aq) Na 2 SO 4 (aq) + 2 H 2 O(l) + 2 CO 2 (g) 5.95 ml 29.8 ml 59.5 ml 119 ml 1.00 L 11. Which of the following is a strong acid? HCl(aq) H 2 SO 4 (aq) HNO 3 (aq) all of the above 12. If 20.0 ml of 0.500 M KOH is titrated with 0.250 M HNO 3, what volume of nitric acid is required to neutralize the base? HNO 3 (aq) + KOH(aq) KNO 3 (aq) + H 2 O(l) 10.0 ml 20.0 ml 25.0 ml 40.0 ml 50.0 ml 13. If 25.0 ml of 0.100 M Ca(OH) 2 is titrated with 0.200 M HNO 3, what volume of nitric acid is required to neutralize the base? 2 HNO 3 (aq) + Ca(OH) 2 (aq) 2 Ca(NO 3 ) 2 (aq) + 2 H 2 O(l) 12.5 ml 20.0 ml 25.0 ml 40.0 ml 50.0 ml
14. If a 50.0 ml sample of ammonium hydroxide is titrated with 25.0 ml of 0.200 M sulfuric acid to a methyl red endpoint, what is the molarity of the base? 2 NH 4 OH(aq) + H 2 SO 4 (aq) (NH 4 ) 2 SO 4 (aq) + 2 H 2 O(l) 0.100 M 0.150 M 0.200 M 0.300 M 0.400 M 15. What is the molarity of a sodium hydroxide solution if 40.00 ml of NaOH is required to neutralize 0.900 g of oxalic acid, H 2 C 2 O 4, (90.04 g/mol)? H 2 C 2 O 4 (aq) + 2 NaOH(aq) Na 2 C 2 O 4 (aq) + 2 H 2 O(l) 0.125 M 0.250 M 0.400 M 0.500 M 0.800 M 16. Given an aqueous solution in which the [ H + ] = 5.0 10 3, what is the molar hydroxide ion concentration? [ OH ] = 2.0 10 10 M [ OH ] = 2.0 10 11 M [ OH ] = 2.0 10 12 M [ OH ] = 5.0 10 11 M [ OH ] = 5.0 10 12 M 17. What is the ph of an aqueous solution if the [ H + ] = 0.1 M? 0 1 2 10 13 18. What is the ph of an aqueous solution if the [ H + ] = 0.000 000 075 M? 0.88 6.12 6.88 7.12 8.88
19. What is the [ H + ] in an acid rain sample that registers 3.22 using a ph meter? 0.51 M 0.017 M 0.0017 M 0.000 17 M 0.000 60 M 20. What is the [ OH ] in a seawater sample if the ph is 8.65? 0.22 M 5.35 M 0.000 004 5 M 0.000 000 002 2 M 0.000 000 004 5 M 21. What is the definition of a strong acid? An acid with a high ph An acid that produces H + An acid that completely dissociates in water An acid that dissolves metals 22. How many moles of calcium metal react to yield of hydrogen gas? 0.250 mol 1.00 mol 2.00 mol Ca(s) + H 2 O(l) Ca(OH) 2 (aq) + H 2 (g) 23. How many moles of oxygen gas react to yield 1.00 mol NO 2? UV NO(g) + O 2 (g) NO 2 (g) 0.250 mol 1.00 mol 2.00 mol
24. What is the molarity of a nitric acid solution prepared by diluting 250.0 ml of 6.00 M HNO 3 to a total volume of 2.50 L? 0.0600 M 0.250 M 0.600 M 2.50 M 6.00 M 25. If 25.0 ml of urine has a mass of 25.725 g and contains 1.929 g of solute, what is the mass/mass percent concentration of the specimen? 1.93% 7.50% 7.72% 37.6% 97.2% 26. What is the mass of solute dissolved in 10.0 g of a 5.00% sugar solution? 0.180 g 0.500 g 0.900 g 9.50 g 10.0 g 27. What is the mass of nickel(ii) nitrate (182.71 g/mol) dissolved in 25.0 ml of 0.100 M Ni(NO 3 ) 2 solution? 0.250 g 0.457 g 4.00 g 45.7 g 457 g 28. Given an aqueous solution in which the [ H + ] = 2.5 10 7, what is the molar hydroxide ion concentration? [ OH ] = 2.5 10 7 M [ OH ] = 2.5 10 8 M [ OH ] = 4.0 10 6 M [ OH ] = 4.0 10 7 M [ OH ] = 4.0 10 8 M
29. Considering the limiting reactant, what mass of cobalt(iii) sulfide (214.07 g/mol) is produced from 0.750 g of cobalt and 0.350 g of sulfur? 2 Co(s) + 3 S(s) Co 2 S 3 (s) 0.779 g 1.36 g 2.34 g 2.72 g 5.45 g 30. What volume of antifreeze must be added to 6 liters of water to produce a mixture that is 40% anti-freeze? 2 L 4 L 6 L 8 L 60 L Answer Key 1. D 2. A 3. A 4. D 5. B 6. A 7. A 8. A 9. D 10. B 11. D 12. D 13. C 14. C 15. D 16. C 17. B 18. D 19. E 20. C 21. C 22. B 23. B 24. C 25. B 26. B 27. B 28. E 29. A 30. B