300 Chemistry Problem Set 14

300 Chemistry Problem Set 14 N. Martel Solutions

1. Identify each substance as being either an electrolyte (ionic compound, acid, base) or a nonelectrolyte (everything else): 1 Sodium chloride 2 Methyl alcohol 3 Glycerol 4 Hydrochloric acid 5 Sugar 6 Sodium hydroxide 7 Ethyl alcohol 8 Acetic acid 9 Ammonium hydroxide 10 Sulfuric acid 11 Barium sulfate 12 Calcium chloride 13 2. Polar molecules dissolve other polar molecules and ionic compounds. Nonpolar molecules dissolve nonpolar molecules. Identify whether or not each substance listed is soluble in two solvents: water and carbon tetrachloride. 14 Sodium chloride 15 Iodine 16 Bromine 17 Potassium nitrate 18 Calcium hydroxide 19 Methanol (CH3OH if you want to draw it) 20 3. Use the solubility above to answer the following questions: 1 What relationship exists between solubility and temperature for most of the substances shown? 2 What are the exceptions? Why do these not follow the relationship you described in a? 3 Approximately how many grams of sodium nitrate will dissolve in 100 g of water at 20 deg C? 4 Approximately how many grams of sodium nitrate will dissolve in 300 g of water at 20 deg C? 5 Approximately how many grams of sodium nitrate will dissolve in 100 g of water at 60 deg C? 6 How many grams of ammonium chloride will dissolve in 1 kg of water at 50 deg C? 7 90 g of sodium nitrate are added to 100 g of water at 0 deg C. With constant stirring, to what temperature must the solution be raised to produce a saturated solution with no solid remaining? 8 Give an example (mass of solute, name of solute, mass of water) of some combination that would make a saturated solution (according to the graph given). 9 Give an example (same idea as h) of some combination that would make an unsaturated solution (according to the graph given). 10 Explain how to take the solution created in i and turn it into a supersaturated solution. 11 A saturated solution of potassium chlorate was made with 300 g of water at 40 deg C. How much potassium chlorate could be recovered by evaporating the solution to dryness? 12 500 g of water are used to make a saturated solution of potassium chloride at 10 deg C. How many more grams of potassium chloride could be dissolved if the temperature were raised to 90 deg C? 13 A saturated solution of potassium nitrate in 200 g of water at 50 deg C is cooled to 20 deg C. How much potassium nitrate will precipitate out of solution? 14 Which salt (ionic compound) is least soluble at 90 deg C? 15 What are the gases shown on the graph? How can you tell? 16 At 60 deg C, 80 g of potassium chlorate is dissolved in 200 g of water. Is the solution unsaturated, saturated, or supersaturated? 17 If a saturated solution of ammonium chloride is formed from 200 g of water, how many grams of ammonium chloride are precipitated when the temperature drops from 70 deg C to 50 deg C? 18 400 g of water are used to make a saturated solution of sodium nitrate at 50 deg C. How much more sodium nitrate could be dissolved if the temperature is raised to 60 deg C? 19 4. Calculate the molarities of the following solutions: 20 2.3 moles of sodium chloride in 0.45 L solution 21 1.2 moles of calcium carbonate in 1.22 L solution 22 0.09 moles of sodium sulfate in 12 mL solution 23 0.75 moles of lithium fluoride in 65 mL solution 1 15.2 g of sodium chloride in 1.25 L solution 2 0.035 g of calcium carbonate in 1.50 L solution 3 1.15 g of sodium sulfate in 15 mL solution 4 5.46 g of lithium fluoride in 250. mL solution 5 5. Explain how you would make the following solutions, in other words, calculate how many grams of each compound you need. You only need to describe the process once. 6 2.15 L of 6.00 M HCl 7 1.50 L of 2.10 M NaOH 8 45 mL of 0.12 M Na2CO3 9 125 mL of 0.75 M LiNO2 10 95 mL of 1.2 M BF3 11 6. What is the molarity of a solution in which 58 g of sodium chloride are dissolved in 1.0 L of solution?

7. What is the molarity of a solution in which 10.0 g of silver nitrate are dissolved in 500. mL of solution?

8. How many grams of potassium nitrate should be used to prepare 2.00 L of a 0.500 M solution?

9. What is the molarity of a solution in which 0.45 g of sodium nitrate are dissolved in 265 mL of solution?

10. What will the volume of a 0.50 M solution be if it contains 25.0 g of calcium hydroxide?

11. How many grams of ammonia are present in 5.0 L of a 0.050 M solution?

12. What is the molality of a solution in which 3.0 moles of NaCl is dissolved in 1.5 kg of water?

13. What is the molality of a solution in which 25.6 g of NaCl is dissolved in 2.45 kg of water?

14. What is the molality of a solution in which 15.0 g of iodine is dissolved in 500. g of alcohol?

15. How many grams of iodine should be added to 750. g of carbon tetrachloride to prepare a 0.020 m solution?

16. How much water should be added to 5.00 g of potassium chloride to prepare a 0.500 m solution?

17. How many grams of beryllium chloride would you need to add to 125 mL of water to make a 0.050 molal solution?

18. Explain how to make at least one liter of 1.25 molal ammonium hydroxide solution.

19. Determine the molality of a solution made by adding 1.65 L of water to 112 g of sodium acetate. 20. Find the percent by volume of solute in a solution made of 15 mL of methanol (CH3OH) and 425 mL of water. If the density of methanol is 0.792 g/mL, find the molarity of the solution.

21. What mass of La(NO3)3 is dissolved in 100 g of water in each of the following: 12 A 0.05 m solution? 13 A 0.05 M solution? 22. A solution containing 66 g C3H6O and 46 g H2O has a density of 0.926 g/mL. Calculate the molarity of the solution.

23. How many mL of 2.0 M HNO3 solution are required to deliver 19.6 g of HNO3?

24. What would the boiling point of a 0.75 m BeF2 solution be?

25. Rank the following three solutions from lowest to highest melting point: 0.25 m barium hydroxide, 0.45 m sugar, 0.65 m sodium hydroxide.

26. Rank the following three solutions from lowest to highest boiling point: 0.25 m barium hydroxide, 0.45 m sugar, 0.65 m sodium hydroxide.

27. What is the boiling point of a solution made from 25 g of NaCl dissolved in 1.0 kg of water?

28. What is the freezing point of the solution described in #27?

29. A solution contains 18.4 g of glycerin, C3H8O3, per 100.0 g water. At what temperature will this solution boil?

30. The molar mass of a molecular compound is 58 g/mol. Calculate the boiling point of a solution containing 24 g of the solute and 600 g of water.

31. Calculate the freezing point of a 0.50 m solution of calcium nitrate.

32. Place the following solutions in order by decreasing freezing point:

1.0 m MgCl2, 1.0 m C6H12O6, 3.0 m AlCl3, 1.0 m NaCl, 6.0 m C3H8O3 33. What are the new freezing and boiling points of a water solution if 50. g of ethylene glycol (molecular compound, molar mass = 62 g/mol) are added to 100. g of water?

34. When 5.00 g of a nonelectrolyte are added to 25.0 g of water, the new freezing point is -2.5 deg C. What is the molecular mass of the unknown compound?

35. Pure benzene, C6H6, freezes at 5.50o C. Calculate the molar mass of a compound if a solution made with 10.0 g of the compound dissolved in 100.0 g of benzene freezes at 5.00o C. The freezing point depression constant for benzene is 5.10o C/m.

36. Calculate the freezing point and the boiling point of a solution of 100 g of ethylene glycol, C2H6O2, in 900 g of water.

37. Calculate the freezing point of a 0.5 m solution of Ca(NO3)2.

38. Place the following solutions in order by decreasing freezing point:

1.0 m C3H8O3 , 1.0 m KCl , 1.0 m MgCl2 39. How would you prepare 2.0 liters of an aqueous solution of CaCl2 that would have a freezing point of -10oC?

40. How many liters of 0.2 M solution of NaOH can be prepared from 300 mL of a 6 M NaOH solution?

41. If 1 liter of 0.5 molar solution is diluted to 5 liters, what is the resulting concentration?

42. 5.00 mL of a 0.1 M Ni(NO3)2 solution is diluted to 8 mL. What is the resulting concentration?

43. How much concentrated 18 M sulfuric acid is needed to prepare 250 mL of a 6.0 M solution?

44. How much concentrated 12 M hydrochloric acid is needed to prepare 100. mL of a 2.0 M solution?

45. To what volume should 25.0 mL of 15 M nitric acid be diluted to prepare a 3.0 M solution? 46. To how much water should 50. mL of 12 M hydrochloric acid be added to produce a 4.0 M solution?

47. To how much water should 100. mL of 18 M sulfuric acid be added to prepare a 1.5 M solution?

48. If I have 340 mL of 0.5 M NaBr solution, what will the concentration be if I add 560 mL more water to it?

49. If I dilute 250 mL of 0.10 M lithium acetate solution to a final volume of 750 mL, what will the concentration of the new solution be?

50. If I leave 750 mL of 0.50 M sodium chloride solution uncovered on a windowsill, and 150 mL of the solution evaporates, what will the new concentration of the sodium chloride solution be?

51. How much water would I need to add to the evaporated solution in #50 to get a solution with a concentration of 0.25 M?

52. NaOH + HCl → H2O + NaCl. Determine the volume of 0.150 M sodium hydroxide solution needed to neutralize 175 mL of 0.885 M hydrochloric acid solution.

53. 2 K3PO4 + 3 NiCl2 → Ni3(PO4)2 + 6 KCl. What volume of 0.225 M potassium phosphate solution is necessary to completely react with 134 mL of 0.0112 M nickel(II) chloride?

54. H3PO4 + 3 KOH → 3 H2O + K3PO4. A 10.0 mL sample of an unknown phosphoric acid solution requires 112 mL of 0.100 M KOH to completely react. What is the concentration of the unknown phosphoric acid solution?

55. 2 Al + 3 H2SO4 → Al2(SO4)3 + 3 H2. What is the minimum amount of 6.0 M sulfuric acid needed to produce 15.0 g of hydrogen?

56. K2S + Co(NO3)2 → 2 KNO3 + CoS. What volume of 0.225 M potassium sulfide solution is required to react completely with 175 mL of 0.115 M cobalt(II) nitrate?

57. Zn + CuCl2 → ZnCl2 + Cu. What is the molarity of zinc chloride that forms when 15.0 g of Zn completely reacts with an excess of copper(II) chloride? (Assume a final volume of 175 mL.)

For additional practice: Relevant sections in textbook are all sections in chapter 15 except sections 15.4 and 15.9 Practice problems are p. 499-501 (1-11, 18-24, 27-28, 30-34, 36-41, 49-51)