p. 309 #1-3, 5-9, 11-15, 17, 18 p. 403 #1, 2, 4-7, 10, 18, 19, 21 p. 358 #1-3, 9, 10 p. 408 #1, 8, 9, 11, 12, 14-18, 20-24, 28, 31-35

Transcription

1 SCH3U Unit 4 Test Review Solutions & Solubility Name: Date: Solutions - Intermolecular/Intramolecular Forces -Ionic, dipole-dipole, hydrogen bonding, London Forces, covalent Like-dissolves-like Other terms: alloy, electrolyte, dissociation, homogenous, Heterogeneous, mixture, non-polar, polar, solute, solution, solvent Properties of Water Qualitative Analysis flame tests, solubility, solution colour Concentration (=solute/solution) Percentage Concentration v/v, w/w, w/v ppm, ppb molarity (M)(mol/L) Solubility Using solubility rules to predict solubility (precipitates) Reading Solubility curves Factors affecting solubility/rate of dissolving Types of saturation (saturated, unsaturated, supersaturated) Solutions Stoichiometry Using molarity (M) & mole ratio as conversion factors: -mole path [volume known (A) moles known (A) moles unknown (B) volume unknown (B)] Making Molar Solutions How to read and use a pipette Making a molar solution from a solid (c=n/v) or from a stock Solution (dilution) C 1V 1 = C 2V 2 Mixing 2 solutions (c = total n/total V) Net Ionic Equations Total Ionic equations & net ionic equations Spectator ions Acids & Bases neutralization Properties of acids & bases, definitions of acids & bases Acid/Base Theories Conjugate acids/bases Strong vs. weak acids (or bases) Indicators Calculating ph/poh given the [H+] and vice versa Titration calculations (Formula - #H x C A x V A = #OH x C B x V B) p. 309 #1-3, 5-9, 11-15, 17, 18 p. 403 #1, 2, 4-7, 10, 18, 19, 21 p. 358 #1-3, 9, 10 p. 408 #1, 8, 9, 11, 12, 14-18, 20-24, 28, Unit 4 Practice Test Questions True/False - Indicate whether the statement is true or false. 1. Hydrogen bonding explains the physical properties of water. 2. Calcium chloride is soluble in water. 3. An Arrhenius acid produces hydroxide ions when dissolved in water. 4. Weak acids only ionize to a small extent when they are dissolved in water. 5. The titrant is the solution in the Erlenmeyer flask. Multiple Choice - Identify the choice that best completes the statement or answers the question. 6. A solution that has a relatively large quantity of solute dissolved in the solvent is a. homogenous b. dilute c. concentrated d. mixed e. saturated 7. The concentration of fluoride ions, F, in municipal drinking water cannot exceed 1.5 ppm. What is the maximum mass of fluoride ions that can be dissolved in 500 ml of water? a mg b. 1.5 mg c. 750 mg d mg e. 3.0 mg

2 9. A solution whose precise concentration is known is called a a. standard solution d. chemical solution b. traditional solution e. concentrated solution c. dilute solution 10. As the temperature of a solution increases, the solubility of salts and the solubility of gases _. a. doesn't change, doesn't change d. decreases, decreases b. increases, decreases e. decreases, increases c. increases, increases 11. A dilute solution of a strong acid can be more dangerous than a concentrated solution of a weak acid because a. there are still more H + (aq) ions in the dilute strong acid b. there are more molecules in the strong acid c. the amount of H + (aq) ions is the same for both d. the strong acid contains chloride ions e. the weak acid has fewer molecules than the strong acid 12. Which of the following is NOT a property of bases? a. They react with active metals. d. They turn red litmus blue. b. They taste bitter and feel slippery. e. They neutralize acids. c. They have a ph greater than Which of the following is the correct representation for a hydronium ion? a. H + (aq) b. H 3 O + (aq) c. H 2 O + (aq) d. H 4 O + (aq) e. none of the above 14. According to its Arrhenius definition, a weak base a. partially reacts with water to form OH (aq) b. fully reacts with water to form OH (aq) c. completely dissociates to form OH (aq) d. has very high ph e. is an ionic hydroxide Matching - Match the term with its correct definition below. a. % V/V e. molar concentration b. concentrated f. dilute c. % W/V g. % W/W d. concentration h. ppm 15. quantity of a given solute in a solution 16. relatively small quantity of solute per unit volume of solution 17. relatively large quantity of solute per unit volume of solution 18. unit used for very low concentrations 19. amount of solute, in moles, dissolved in one litre of solution 20. concentration expressed as mass of solute in volume of solution 21. concentration expressed as solute volume in solvent volume 22. concentration expressed as solute mass in solvent mass

3 15. Communication 23. As temperature increases, the solubility of NaNO 3 in water increases and the solubility of oxygen decreases. Give reasons for these different solubility trends. 24. How does dilution affect the ph of (a) acidic solutions? (b) basic solutions? 25. Identify the two acid-base conjugate pairs in the following reaction: HF (aq) + H 2 O (l) H 3 O + (aq) + F (aq) Problem (Thinking/Inquiry) 26. Concentrated hydrogen peroxide in high school labs is 30% W/V H 2 O 2 dissolved in water. Calculate the mass of pure H 2 O 2 dissolved in a 450-mL bottle? 27. What concentration results from mixing 400 ml of a 2.0 mol/l HNO 3 solution with 600 ml of a 3.0 mol/l HNO 3 solution? 28. Students in a chemistry lab are making the compound cobalt (II) carbonate. It can be made by reacting sodium carbonate solution with cobalt (II) chloride solution. Calculate the volume of 1.0 mol/l cobalt (II) chloride solution required to completely react with 250 ml of 1.5 mol/l sodium carbonate. 29. Assume that the solubility of carbon dioxide gas in pop at 5ºC is g/100 ml (supersaturated) and at 20ºC its solubility is g/100 ml. What mass of carbon dioxide gas will escape from a 355-mL can of Coke that has been taken out of the fridge and has been sitting open at 20ºC? 30. A student has accidentally spilled ml of 3.0 mol/l nitric acid onto the lab bench. What mass of sodium bicarbonate would the teacher need to sprinkle on this spill to neutralize and clean it up? Answer Section TRUE/FALSE 1. T 2. T 3. F 4. T 5. F 6. C 7. A 8. E 9. A 10. B 11. A MULTIPLE CHOICE 12. A 13. B 14. A MATCHING 15. D 16. F 17. B 18. H 19. E 20. C 21. A 22. G SHORT ANSWER 23. ANS: Sodium nitrate is an ionic solid and will dissolve more easily as temperature increases because warmer water has greater heat energy to overcome the attractive forces between the sodium and nitrate ions. Oxygen is a gas and its molecules must gain more energy to overcome the attractive forces of the water molecules and escape the solution. 24. ANS: (a) Diluting acidic solutions decreases the hydrogen ion concentration. This increases the ph and makes these solutions less acidic. (b) Diluting basic solutions decreases the ph and makes these solutions less basic.

4 25. ANS: HF (aq) and F (aq) are conjugate acid-base pairs. H 3 O + (aq) and H 2 O (l) are conjugate acid-base pairs. PROBLEM 26. ANS: The mass of pure hydrogen peroxide 140 g. 27. ANS: The concentration upon mixing the nitric acid solutions is 2.6 mol/l. 28. ANS: Na 2 CO 3(aq) + CoCl 2(aq) 250 ml v 1.5 mol/l 1.0 mol/l CoCO 3(s) + 2 NaCl (aq)

5 The volume of cobalt(ii) chloride required is 380 ml. 29. ANS: The mass of carbon dioxide bubbling out of the Coke is 1.48 g. 30. ANS: HNO 3(aq) + NaHCO 3(s) ml g/mol 3.0 mol/l m CO 2(g) + H 2 O (l) + NaNO 3(aq) The teacher would sprinkle 25.2 g of baking soda to neutralize the acid spill.