5. What is the name of the phase transition that occurs when a solid is converted directly into a gas (without going through the liquid phase)?

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Lenard Sutton
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1 1. If the volume of a confined gas is doubled while the temperature remains constant, what change (if any) would be observed in the pressure? a. It would be half as large. b. It would double. c. It would be four times as large. d. It would be 1/4 as large. e. It would remain the same. 2. A given mass of gas in a rigid container is heated from 100 C to 500 C. Which of the following responses best describes what will happen to the pressure of the gas? a. The pressure will decrease by a factor of five. b. The pressure will increase by a factor of five. c. The pressure will increase by a factor of about two. d. The pressure will increase by a factor of about eight. e. The pressure will increase by a factor of about twenty-five. 3. The pressure of a gas will? when the volume is decreased and will? when the absolute temperature is decreased. (a) increase...increase (b) increase...decrease (c) decrease...increase (d) decrease...decrease 4. For a gas, which pair of variables are inversely proportional to each other (if all other conditions remain constant)? (a) P, T (b) P, V (c) V, T (d) n, V (e) n, P 5. What is the name of the phase transition that occurs when a solid is converted directly into a gas (without going through the liquid phase)? (a) melting (b) boiling (c) condensing (d) sublimation 6. Which if the following statements are true about the Eutectic point on a two component (compounds A and B) phase diagram? a. Both compounds are solid b. The melting point of the mixture is lower than the melting points of either of the individual compounds c. One compound is in the liquid phase whilst the other is in the solid phase d. It always occurs when the ratio of compound A to compound B is 50:50

2 7. Which of the following statements is NOT true in relation to the triple point on a single component phase diagram? a. The point at which the solid, liquid and gaseous phases for a substance co-exist b. The triple point exists for a substance occurs at a specific temperature and pressure c. The triple point exists at a single temperature and is independent of pressure d. The system must be enclosed so that no vapour can escape 8. The degree of freedom at triple point in phase diagram for water is: (a) 0 (b) 1 (c) 2 (d) 3 9. A buffer solution contains M HC 2 H 3 O 2 and M NaC 2 H 3 O 2. The ph of this solution is : Ka for HC 2 H 3 O 2 is 1.8x10-5. (a) 4.43 (b) 3.25 (c) 1.2 x 10-4 (d) 5.57 (e) Which one of the following statements concerning active pharmaceutical ingredients (APIs) is false? a. The degree of ionisation of an API is dependent upon its pk a or pk b. b. The degree of ionisation of an API is dependent upon the ph of the surrounding solution. c. The extent to which an API may be absorbed is influenced by the extent of its ionisation d. APIs pass through biological membranes more readily when they are ionised e. Temperature can affect the degree of ionisation of APIs 11. What does a buffer do? a) Keeps the ph of a solution constant b) Keeps the salt concentration of a solution constant c) Keeps the cation concentration constant d) Keeps the anion concentration constant 12. What substances are present in a buffer? a) A weak base or acid and its salt b) A hydrolyzing salt only c) A weak base or acid only d) A salt only 13. Of the following solutions, which has the greatest buffering capacity? A) M NH3 and M NH4Cl B) M NH3 and M NH4Cl C) M NH3 and M NH4Cl D) M NH3 and M NH4Cl E) They are all buffer solutions and would all have the same capacity.

3 14. The Henderson-Hasselbalch equation is.c 15. In a solution, when the concentrations of a weak acid and its conjugate base are equal, A) the system is not at equilibrium. B) the buffering capacity is significantly decreased. C) the -log of the [H+] and the -log of the Ka are equal. D) all of the above are true. 16. Consider a solution which is 0.10 M in CH 3 COOH and 0.20 M in NaCH 3 COO. Which of the following statements is true? (a) If a small amount of NaOH is added, the ph decreases very slightly. (b) If NaOH is added, the OH - ions react with the CH 3 COO - ions. (c) If a small amount of HCl is added, the ph decreases very slightly. (d) If HCl is added, the H + ions react with CH 3 COOH ions. (e) If more CH 3 COOH is added, the ph increases. 17. A buffer was prepared by mixing 1.00 mole of ammonia and 1.00 mole of ammonium chloride to form an aqueous solution with a total volume of 1.00 liter. To 500 ml of this solution was added 30.0 ml of 1.00 M NaOH. What is the ph of this solution? (a) 8.96 (b) 9.83 (c) 9.31 (d) 9.11 (e) How many grams of NaF would have to be added to 2.00 L of M HF to yield a solution with a ph = 4.00? (a) 300 g (b) 36 g (c) 0.84 g (d) 6.9 g (e) 60. g 19. A solution is made by dissolving some salt in a beaker of water. The salt is referred to as the A. solute B. filtrate C. solution D. solvent 20. What is the concentration, in % (m/v) of a solution containing 15.0 g KCl in ml solution? A. 5.00% B. 2.00%

4 C % D. 2.50% 21. How many ml of 2.50% (m/v) salt solution would contain 1.80 g of salt? A. 105 ml B. 104 ml C ml D ml 22. What is the molarity of a solution that contains 1.50 mol HCl in 2.50 L of solution? A M B M C M D. 1.40M 23. How many moles of C12H22O11 are needed to prepare 2.50 L of M solution? A mol B mol C mol D mol 24. What is the molarity of a NaNO3 solution made by diluting ml of a 1.60 M solution to a final volume of 400. ml? A M B M C M D M 25. In which of the following phases can a solution be made? A. Solid and liquid phases only B. Gas and solid phases only C. Liquid and gas phases only D. Solid, liquid and gas phases 26. If a solute dissolves in a solvent, what is likely to be true? a. The solute-solute attractions are greater than the solvent-solvent attractions. b. The solute-solute attractions are less than the solvent-solvent attractions. c. The solute-solvent attraction is greater than the sum of the solute-solute and solvent-solvent attraction. d. There is a strong attraction between solute and solvent molecules. 27. What is the term for a substance that provides ions when dissolved in water? a. An electrolyte b. A non-electrolyte c. A molecular solute d. A covalent compound

5 28. At 75 o C, the vapour pressure of pure water is 39 kpa. Which one of the following is the most likely vapour pressure for a 1.5 M solution of sucrose (aq) at the same temperature? a. 37 kpa b. 39 kpa c. 0 kpa d. 41 kpa grams of sugar are added to 0.5 liter of water. The vapor pressure of this solution is than pure water. The freezing point of this solution is than pure water. a. lower, lower b. higher, higher c. lower, the same as d. higher, lower e. lower, higher 30. Which one of the following is not a characteristic of a zero-order drug decomposition reaction? a) The rate of reaction is constant b) The rate of reaction is independent of the concentration of any of the reactants c) The half-life of the drug decomposition is directly proportional to the initial concentration of API. d) The units of the rate constant (k) are time When the results of a drug degradation study are plotted on a graph, a plot of the logarithm of the amount of API remaining against time gives a straight line. Which one of the following is true? a) The units of the rate constant (k) are concentration -1 time -1 b) The reaction is zero-order c) The half-life may be represented by t 0.5 = 0.693/k d) The half-life is directly related to the initial concentration of the reactant 32. Regarding zero-order reactions, which one of the following is true? a) The half-life may be represented by the expression t 0.5 = 0.693/k b) The rate of degradation is independent of the concentration of the reactant(s) c) A plot of the concentration remaining against time is a straight line with a gradient of 1/k d) The units of the rate constant (k) are time A drug solution decomposes via first-order kinetics with a rate constant, k, of days -1. What is the half-life of the drug in solution? a) day b) 33 days c) 70 days d) 90 days

6 34. A drug has the initial concentration of 5.0 x 10-3 g cm -3 in aqueous solution. After 24 months, the concentration drops to 3.48 x 10-3 g cm -3. This degradation process is known to follow first-order kinetics. Which one of the following is the rate constant for this reaction: a) -1.5 x 10-2 month -1 b) 1.5 x 10-2 month -1 c) 3.2 x 10-2 month -1 d) 3.0 x 10-2 month The reaction A + B = products is found to be second order in [A] and first order in [B]. The rate equation would be: a) R = k[a][b] b) R = k[a] 2 [B] c) R = k[a][b]2 d) R = k[b] e) R = k[a] Which one of the following is NOT true? Different polymorphs forms of a drug can have different: a) Melting points b) Molecular formulae c) Solubilities d) Crystal habits

7 1 A 13 A 25 D 2 C 14 C 26 D 3 B 15 C 27 A 4 B 16 C 28 A 5 D 17 C 29 A 6 B 18 E 30 D 7 C 19 A 31 C 8 A 20 D 32 B 9 A 21 D 33 D 10 D 22 B 34 B 11 A 23 A 35 B 12 A 24 B 36 B

CP Chapter 15/16 Solutions What Are Solutions?

CP Chapter 15/16 Solutions What Are Solutions? What is a solution? A solution is uniform that may contain solids, liquids, or gases. Known as a mixture Solution = + o Solvent The substance in abundance