Part A Answer all questions in this part.

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Elisabeth Tyler
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1 Part A Directions (1-24): For each statement or question, record on your separate answer sheet the number of the word or expression that, of those given, best completes the statement or answers the question. Some questions 1 Which characteristics will both generally decrease when elements in Period 3 on the Periodic Table are considered in order from left to right? (1) nonmetallic and atomic radius (2) metallic and atomic radius (3) metallic and ionization energy (4) nonmetallic and ionization energy 2 When 5 grams of KCl are dissolved in 50. grams of water at 25 C, the resulting mixture can be described as (1) heterogeneous and supersaturated (2) heterogeneous and unsaturated (3) homogeneous and unsaturated (4) homogeneous and supersaturated 3 Which of the following compounds is least soluble in water at 60. C? (1) KNO 3 (3) NH 4Cl (2) KClO 3 (4) NaCl 4 What is the average atomic mass of element X if a sample of X is composed of 85% X-127, 12% X-130, and 3% X-128? (1) amu (3) amu (2) amu (4) amu 5 Which compound becomes less soluble in water as the temperature of the solution is increased? (1) KCl (3) NaCl (2) HCl (4) NH 4Cl 6 An orbital is a region of space where there is a high probability of finding (1) an electron (3) a neutron (2) a positron (4) a proton 7 A gas sample is at 25 C and 1.0 atmosphere. Which changes in temperature and will cause this gas to behave more like an ideal gas? (1) increased temperature and increased (2) decreased temperature and increased (3) increased temperature and decreased (4) decreased temperature and decreased 8 Lithium and potassium have similar chemical because the atoms of both elements have the same (1) atomic number (2) number of electron shells (3) mass number (4) number of valence electrons 9 Which intermolecular force of attraction accounts for the relatively high boiling point of water? (1) covalent bonding (3) ionic bonding (2) hydrogen bonding (4) metallic bonding 10 What is the molarity of 1.5 liters of an aqueous solution that contains 52 grams of lithium fluoride, LiF? [gram-formula mass of LiF = 26 grams/mole] (1) 3.0 M (3) 1.3 M (2) 2.0 M (4) 0.75 M 11 A dilute, aqueous potassium nitrate solution is best classified as a (1) heterogeneous mixture (2) homogeneous compound (3) homogeneous mixture (4) heterogeneous compound

2 12 Given the balanced equation representing a reaction: 4 NH 3 + 5O 2 4 NO + 6 H 2O What is the minimum number of moles of O 2 that are needed to completely react with 16 moles of NH 3? (1) 20. mole (3) 64 mole (2) 80. mole (4) 16 mole 13 Which type of substance can conduct electricity in the liquid phase but not in the solid phase? (1) ionic compound (2) metallic element (3) nonmetallic element (4) molecular compound 14 An assumption of the kinetic molecular theory of gases is that the particles of a gas have (1) little attraction for each other and a significant volume (2) strong attraction for each other and a significant volume (3) strong attraction for each other and an insignificant volume (4) little attraction for each other and an insignificant volume 15 The molecular formula of a compound is represented by X 3Y 6. What is the empirical formula of this compound? (1) XY 3 (3) X 3Y (2) X 2Y (4) XY 2 16 What is the total mass of solute in 1,000. grams of a solution having a concentration of 5 parts per million? (1) g (3) 0.5 g (2) 0.05 g (4) 5 g 17. In which sample is the average kinetic energy the greatest? (1) 15 ml of H 2O (l ) at 30. C (2) 10. ml of HCl (aq) at 25 C (3) 15 ml of HCl (aq) at 20. C (4) 10. ml of H 2O (l ) at 35 C 18 The process of filtration is performed in the laboratory to (1) remove water from solutions (2) separate insoluble substances in an aqueous mixture (3) form precipitates (4) separate dissolved particles from the solvent 19 The percent composition by mass magnesium in MgBr 2 (gram-formula mass = 184 g/mol) is equal to (1) (3) (2) (4) The percent composition by mass of nitrogen in NH 4OH (gram-formula mass = 35 grams/mole) is equal to (1) 17% (3) 45% (2) 40% (4) 67% 21 If an element, X, can form an oxide that has the formula X 2O 3, then element X would most likely be located on the Periodic Table in the same group as (1) In (3) Ba (2) Cd (4) Na 22 Two solid samples each contain only sulfur, oxygen, and sodium. These samples have the same color, melting point, density, and reaction with an aqueous barium chloride solution. It can be concluded that the two samples are the same (1) compound (3) element (2) solution (4) mixture 23 Which aqueous solution of KI freezes at the lowest temperature? (1) 2 mol of KI in 1,000 g of water (2) 1 mol of KI in 1,000 g of water (3) 1 mol of KI in 500 g of water (4) 2 mol of KI in 500 g of water 24 What is the total charge of the nucleus of a carbon atom? (1) +6 (3) 6 (2) +12 (4) 0 P.S./Chem November 18 [2] [OVER]

3 Part B 1 Directions (25-40): For each statement or question, record on your separate answer sheet the number of the word or expression that, of those given, best completes the statement or answers the question. Some questions 25 An element that is malleable and a good conductor of heat and electricity could have an atomic number of (1) 16 (3) 29 (2) 18 (4) The chemical bond between which two atoms is the most polar? (1) Si O (3) H H (2) S Cl (4) C N 27 A solid substance is an excellent conductor of electricity. The chemical bonds in this substance are most likely (1) metallic, because the valence electrons are mobile (2) metallic, because the valence electrons are stationary (3) ionic, because the valence electrons are mobile (4) ionic, because the valence electrons are shared between atoms 32 The two forms of oxygen, O 2 (g) and O 3 (g), have (1) identical molecular structures and different (2) identical molecular structures and identical (3) different molecular structures and different (4) different molecular structures and identical 33 In a chemical reaction there is conservation of (1) energy, volume, and mass (2) mass, charge, and energy (3) energy, volume, and charge (4) mass, charge, and volume 34 Under which conditions of temperature and is a gas most soluble in water? (1) high temperature and high (2) high temperature and low (3) low temperature and low (4) low temperature and high 28 What is the concentration of O 2 (g) in parts per million in a solution that contains grams of O 2 (g) dissolved in 1,000.grams of H 2O (l )? (1) 0.8 ppm (3) 80 ppm (2) 8 ppm (4) 800 ppm 29 Which substance can be decomposed by chemical means? (1) ammonia (3) oxygen (2) phosphorus (4) silicon 30 A 3.0 M HCl (aq) solution contains a total of (1) 3.0 moles of HCl per liter of solution (2) 3.0 grams of HCl per mole of solution (3) 3.0 grams of HCl per liter of water (4) 3.0 moles of HCl per mole of water 31 What is the total mass of KNO 3 that must be dissolved in 50. grams H 2O at 60 C to make a saturated solution? (1) 32 g (3) 64 g (2) 53 g (4) 106 g 35 Which of the following compounds is insoluble in water? (1) potassium bromide (2) sodium bromide (3) calcium bromide (4) silver bromide 36 An unsaturated aqueous solution of NH 3 is at 90. C in 100. grams of water. According to the Table G, how many grams of NH 3 could this unsaturated solution contain? (1) 5 g (3) 15 g (2) 10. g (4) 20. g 37 The molarity of an aqueous solution of NaCl is defined as the (1) grams of NaCl per liter of solution (2) grams of NaCl per liter of water (3) moles of NaCl per liter of solution (4) moles of NaCl per liter of water P.S./Chem November 18 [3] [OVER]

4 38 An unsaturated solution is formed when 80. grams of a salt is dissolved in 100. grams of water at 40. C. This salt could be (1) KNO 3 (3) KCl (2) NaNO 3 (4) NaCl 39 A gas has a of 40.0 kpa, a temperature of 400. K, and a volume of 50.0 milliliters. What volume will the gas have at a of 20.0 kpa and a temperature of 200. K? (1) 100. ml (3) 50.0 ml (2) 200. ml (4) 12.5 ml 40 The graph below represents uniform cooling of a sample of a pure substance, starting as a gas. Solid and liquid phases can exist in equilibrium between points (1) E and F (3) B and C (2) C and D (4) D and E P.S./Chem November 18 [4] [OVER]

5 Mass of NH4Br (in g) per 100. g H2O Part B 2 Directions (41-44): Record your answers in the spaces provided in your answer booklet. Some questions Base your answer to question 41 and 42 on the information below and on your knowledge of chemistry. Scientists who study aquatic ecosystems are often interested in the concentration of dissolved oxygen in water. Oxygen, O2, has a very low solubility in water, and therefore its solubility is usually expressed in units of milligrams per 100. grams of water at 1.0 atmosphere. The graph below shows a solubility curve of oxygen in water. Solubility of Oxygen in Water versus Temperature 41 Explain, in terms of molecular polarity, why oxygen gas has a low solubility in water. [1] 42 A student determines that 4.1 milligrams of oxygen is dissolved in 100. grams of water at 15 C and 1.0 atmosphere. Based on the graph shown, in terms of saturation, what type of solution is the sample? [1] Base your answer to question 43 and 44 on the information below and on your knowledge of chemistry. The compounds NH 4Br (s) and NH 3 (g) are soluble in water. Solubility data for NH 4Br (s) in water are listed in the table below. Solubility of NH 4Br in H 2O Solubility of NH 4Br in H 2O vs. Temperature 150 Temperature Mass NH 4Br per ( C) 100. g H 2O (g) Temperature ( C) 43 Plot the NH 4Br solubility data on the graph provided. Circle and connect the points with a line. [1] 44 Determine the mass of NH 4Br (s) required to form a saturated solution in 200. grams H 2O at 60 C. [1] Part C P.S./Chem November 18 [5] [OVER] 90 60

6 Directions (45-48): Record your answers in the spaces provided in your answer booklet. Some questions Base your answer to questions 45 and 46 on the information below and on your knowledge of chemistry. A solution is made by completely dissolving 90. grams of KNO 3 (s) in 100. grams of water in a beaker. The temperature of the solution is 65 C. 45 Describe the effect on the solubility of KNO 3 (s) if the on the solution increases. [1] 46 Determine the mass of KNO 3 that settles to the bottom of the beaker when the solution is cooled to 15 C. [1] Base your answer to question 47 and 48 on the information below and on your knowledge of chemistry. In a laboratory, a student makes a solution by completely dissolving 80.0 grams of KNO 3 (s) in 100. grams of hot water. The resulting solution is at a temperature of 60. C. The temperature in the laboratory is 22 C. 47 In terms of saturation, describe the solution made by the student. [1] 48 Compare the boiling point of the KNO 3 solution at standard to the boiling point of water at standard. [1] P.S./Chem November 18 [6] [OVER]

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