Unit 10: Solutions and Solubility REGENTS CHEMISTRY

Transcription

1 Name: Unit 10: Solutions and Solubility REGENTS CHEMISTRY 1

2 Name: Unit 10: Solutions and Solubility Matter is classified as a pure substance or as a mixture of substances. (3.1q) Mixtures are composed of two or more different substances that can be separated by physical means. When different substances are mixed together, a homogeneous or heterogeneous mixture is formed.(3.1s) The proportions of components in a mixture can be varied. Each component in a mixture retains its original properties. (3.1t) The three phases of matter (solids, liquids, and gases)have different properties.(3.1kk) Differences in properties such as density, particle size, molecular polarity, boiling point and freezing point, and solubility permit physical separation of the components of the mixture. (3.1nn) A solution is a homogeneous mixture of a solute dissolved in a solvent. The solubility of a solute in a given amount of solvent is dependent on the temperature, the pressure, and the chemical natures of the solute and solvent. (3.1oo) The concentration of a solution may be expressed as molarity (M), percent by volume, percent by mass, or parts per million (ppm). (3.1pp) The addition of a nonvolatile solute to a solvent causes the boiling point of the solvent to increase and the freezing point of the solvent to decrease. The greater the concentration of particles, the greater the effect. (3.1qq) 2

3 Name: Unit 10: Solutions and Solubility For each word, provide a short but specific definition from YOUR OWN BRAIN! No boring textbook definitions. Write something to help you remember the word. Explain the word as if you were explaining it to an elementary school student. Give an example if you can. Don t use the words given in your definition! Solute: Solvent: Solution: Heterogeneous Mixture: Vapor Pressure: Viscosity: Surface Tension: Solubility: Saturated: Unsaturated: Supersaturated: Concentrated: Dilute: Molarity: Parts Per Million: Freezing Point Depression: Boiling Point Elevation: Chromatography: Precipitate: 3

4 Name: Unit 10: Solutions and Solubility 1. Draw the following descriptions: Pure element Pure compound Mixture of Mixture of Mixture of two elements an element & two diatomic a compound elements & a compound 2. Classify each of the following with the combination of terms listed below. pure substance element pure substance compound mixture homogeneous mixture heterogeneous a. HCl (aq) d. sugar (C 11 H 22 O 11 ) g. KBr (s) j. Soil b. Cl 2 (g) e. water h. CH 2 (OH) 2 (aq) k. Sodium c. Hg (l) f. iron oxide i. NH 3 (l) l. salt water 3. Matter that is composed of two or more different elements chemically combined in a fixed proportion is classified as (1) a compound (2) an element (3) a mixture (4) a solution 4. A compound differs from an element in that a compound (1) is homogeneous (3) can be decomposed by a chemical reaction (2) has a definite composition (4) has a definite melting point 5. A compound differs from a mixture in that a compound always has a (1) homogeneous composition (3) minimum of three elements (2) maximum of two elements (4) heterogeneous composition 6. A heterogeneous material may be (1) an element (2) a compound (3) a pure substance (4) a mixture 7. Which statement is an identifying characteristic of a mixture? (1) a mixture can consist of a single element (2) a mixture can be separated by physical means (3) a mixture must have a definite composition by weight (4) a mixture must be homogeneous 8. Which must be a mixture of substances? (1) solid (2) liquid (3) gas (4) solution 9. Which substance can be decomposed by chemical means? (1) aluminum (2) octane (3) silicon 4

5 Name: Unit 10: Solutions and Solubility 10. Two substances, A and Z, are to be identified. Substance A cannot be broken down by a chemical change. Substance Z can be broken down by a chemical change. What can be concluded about these substances? (1) Both substances are elements. (2) Both substances are compounds. (3) Substance A is an element and substance Z is a compound. (4) Substance A is a compound and substance Z is an element. 11. Which terms are used to identify pure substances? (1) an element and a mixture (3) a solution and a mixture (2) an element and a compound (4) a solution and a compound 12. Two different samples decompose when heated. Only one of the samples is soluble in water. Based on this information, these two samples are (1) both the same element (3) both the same compound (2) two different elements (4) two different compounds 13. Tetrachloromethane, CCl 4, is classified as a (1) compound because the atoms of the elements are combined in a fixed proportion (2) compound because the atoms of the elements are combined in a proportion that varies (3) mixture because the atoms of the elements are combined in a fixed proportion (4) mixture because the atoms of the elements are combined in a proportion that varies 14. Fill in the tables below. Solution Solute Name Formula Solvent Formula Solution Name Solute Formula MgBr 2 (aq) aqueous potassium nitrate K 2 SO 4 (aq) aqueous sodium acetate FeCl 3 (aq) aqueous ammonium hydroxide CuSO 4 (aq) aqueous lithium bromide Ba(NO 3 ) 2 (aq) aqueous magnesium hypochlorite (NH 4 ) 2 CO 3 (aq) aqueous iron (II) nitrate 5

6 Section 1 Solubility Rules Matter is classified as a pure substance or as a mixture of substances. Mixtures are composed of two or more different substances that can be separated by physical means. When different substances are mixed together, a homogeneous or mixture is formed. The proportions of components in a mixture can be varied. Each component in a mixture its original properties. Differences in properties such as density, particle size, molecular polarity, boiling point and freezing point, and solubility permit separation of the components of the mixture. A solution is a mixture of a solute dissolved in a solvent. The solubility of a solute in a given amount of solvent is dependent on the temperature, the pressure, and the chemical natures of the solute and solvent. 1. Why does water have a strong surface tension and high viscosity? 2. Give examples of homogeneous and heterogeneous mixtures: 3. In sweet tea, what are the solute and solvent? 4. Is sweet tea aqueous? How do you know? 5. The solubility of sweet tea is 209 grams per 100 g of water at 20C. Explain what this means. 6. What could you do to make more sweet tea sugar dissolve in the 100g of water? 6

7 Use Table F to determine if the following compounds are soluble or insoluble. a. NaCl e. K 3 PO 4 i. calcium hydroxide b. PbBr 2 f. MgCO 3 j. copper (II) hydroxide c. CaSO 4 g. NH 4 NO 3 k. lead(ii) sulfate d. potassium chromate h. sodium hydrogen carbonate l. ammonium sulfide Key: I Insoluble S Soluble Acetate Bromide Carbonate Chlorate Chloride Chromate Hydroxide Hydrogen Carbonate Iodide Nitrate Perchlorate Phosphate Sulfate Sulfide Aluminum Ammonium Barium Calcium Dimercury Copper II Iron II Iron III Lithium Lead Magnesium Potassium Silver Sodium Strontium Zinc 7

8 1. Double replacement reactions require the cations to switch with the anions. Identify which of the following DR reactions are written correctly. Correct the mistakes in the wrong reactions: a. (NH 4 ) 3 PO 4(aq) + AlCl 3(aq) à Al(PO 4 ) 3(s) + NH 4 Cl 3(aq) b. NaCl (aq) + AgNO 3(aq) à AgCl (S) + NaNO 3(aq) c. NaBr (aq) + PbI 2(aq) à NaI (aq) d. K 2 SO 4(aq) + BaI 2(aq) à BaSO 4(s) + 2KI (aq) e. CaCl 2(aq) + Li 2 CO 3(aq) à 2LiCl (s) + CaCO 3(aq) 2. Write the balanced chemical equation for each of the following descriptions. Use Table F to determine the state of the reactants and products (s) or (aq). Write soluble or insoluble under each reactant and product. Square off the precipitate. (a) Solutions of sodium carbonate and silver nitrate are mixed to form sodium nitrate and silver carbonate. (b) AgC 2 H 3 O 2 (aq) is mixed with NaCl (aq) to form AgCl and NaC 2 H 3 O 2. (c) Solutions of potassium sulfate and calcium chlorate are mixed to form potassium chlorate and calcium sulfate. (d) CaCl 2 (aq) and Na 2 S (aq) are mixed to form CaS and NaCl. (e) What do all the above double replacement reactions have in common? 8

9 Section 2 Factors affecting solubility The Table below lists 5 factors that may affect the rate at which solids and gases dissolve. Fill in the table by indicating if the rate of dissolving increasing, decreases, or is not effected. Then explain why. Factor Affect on Solid Solute Affect on Gaseous Solute A factory releases clean, warm water into a stream. The stream becomes severely polluted as a result. How does this happen? Fish living in the water depend on dissolved oxygen in order to breathe. Like other gases, oxygen molecules tend to spread out. In order to dissolve them, it is necessary to confine them. Heat speeds the molecules up and makes them spread out more- exactly the opposite of what needed to dissolve them. As a result, heat drives the oxygen out of the water, causing the fish to die. The dead fish begin to decay. Growing decay bacteria deplete the water of oxygen even further. In this way, clean warm water can pollute a stream. The process of dissolving gases is the opposite to the process of dissolving solids because of the differences between gases and solids. 9

10 Answer the questions below based on the reading above and your knowledge of chemistry. 1. A warm can of soda is dropped and bounces down a flight of stairs. When it is opened, carbon dioxide gas coming out of solution causes it to spray all over. Explain the effect of each of the following: a. The fact that the soda was warm. b. The fact that the soda was dropped and bounced down a flight of stairs. c. The fact that the can was opened 2. When a gas dissolves, the particles need to be confined. What do the particles of a solid need to do in order to dissolve? 3. Sugar is added to a hot cup of coffee and stirred. The sugar dissolves. Explain the effect of each of the following: a. The fact that the coffee was hot. b. The fact that the coffee was stirred. 4. Which dissolves faster, a teaspoon of sugar or a sugar cube? Why? 5. A solid is added to water and stirred. Some of it dissolves, but not all. What happens to the rate at which the solid dissolving between it was first added and when it stopped dissolving? Explain. 10

11 Section 3 Saturation Curves 1. When a solution is holding as much solute as it can at that temperature, the solution is called saturated. How can you tell a solution is saturated? Just by looking at it? Or do you have to do more? 2. When a solution is unsaturated in can hold more solute at that temperature. How can you tell a solution is unsaturated? 3. When a solution is supersaturated it is holding more solute than it should at that temperature. How can you make a supersaturated solution? 4. What type/phase of solutes: a. increase in solubility with an increase in temperature? b. decrease in solubility with an increase in temperature? c. increase in solubility with an increase in pressure? 5. Using Table G, answer the following: a. How many grams of KI dissolve at 10C? b. How many grams of NaNO 3 dissolve at 10C? c. Which salt is more concentrated at 10C, NaNO 3 or KI? d. At what temperature will 30g of KCl dissolve? e. At what temperature will 60 grams of NH 4 Cl dissolve? f. How many more grams of KClO 3 will dissolve if the temperature is changed from 20C to 50C? g. How many grams will precipitate out of KNO 3 if the temperature is changed from 60C to 0C? h. 40g of NaCl is added to 100 g of water at 100C. What type of solution is this? i. 20 grams of KClO 3 is added to 100g of water at 40C. What type of solution is this? j. 10 g of NH 3 is added to 100g of water at 70C. What type of solution is this? 11

12 6. State whether each of the following solutions is saturated, unsaturated, or supersaturated. (a) 80 g NaNO 3 in 100 g H 2 O at 10ºC (b) 90 g KNO 3 in 100 g H 2 O at 50ºC (c) 90 g KI in 100 g H 2 O at 50ºC (d) 5 g KClO 3 in 100 g H 2 O at 5ºC (e) 40 g KCl in 50 g H 2 O at 60ºC (f) 35 g NaNO 3 in 50 g H 2 O at 10ºC (g) 5 g KClO 3 in 50 g H 2 O at 5ºC (h) 30 g NH 4 Cl in 200 g H 2 O at 10ºC (i) 40 g SO 2 in 200 g H 2 O at 5ºC 7. Tell how many MORE grams of each solute must be added to 100 g of water to form a saturated solution at that temperature. Grams Solute per 100 g H 2 O a. 35 g KNO 3 at 40ºC b. 50 g NH 3 at 10ºC c. 15 g KCl at 75ºC Solute Added to make Saturated Grams Solute per 100 g H 2 O d. 35 g NaCl at 90ºC e. 5 g NH 3 at 90ºC f. 10 g KClO 3 at 40ºC Solute Added to make Saturated Grams Solute per 200 g H 2 O g. 25 g NH 3 at 5ºC h. 30 g NaNO 3 at 50ºC j. 15 g KClO 3 at 75ºC Solute Added to make Saturated 8. Tell how many grams of each solute will crystallize/precipitate/settle. Assume all solutions are saturated and in 100 grams of H 2 O. Amount cooled a. KNO 3 (aq) is cooled from 70ºC to 40ºC b. NH 4 Cl (aq) is cooled from 90ºC to 20ºC c. KCl (aq) is cooled from 55ºC to 30ºC d. KI (aq) is cooled from 20ºC to 5ºC Amount Precipitated Amount cooled e. NaCl (aq) is cooled from 100ºC to 40ºC f. KNO 3 (aq) is cooled from 65ºC to 25ºC g. KClO 3 (aq) is cooled from 100ºC to 40ºC h. NaNO 3 (aq) is cooled from 45ºC to 10ºC Amount Precipitated 9. Rank the following solids in order from least to most soluble in 100 g H 2 O at 50ºC : NH 4 Cl, NaNO 3, KClO 3, KNO 3 12

13 10. Rank the following gases in order from least to most soluble in 100 g H 2 O at 50ºC : NH 3, SO 2, HCl Section 4 Molarity and Concentration Concentration The concentration of a solution may be expressed as (M), percent by volume, percent by mass, or parts per (ppm). 1. Give an example of a solution that could be concentrated but unsaturated. 2. Give an example of a solution that is dilute but supersaturated. 3. A solution is created with 2 moles of NaCl in 1.5L of solution. Calculate the molarity. 4. A solution is created with 3.5 moles of NaCl in 250mL of solution. Calculate the molarity. 5. A solution is created with 25.0 grams of NaCl in 1.0L of solution. Calculate the molarity. 6. A solution is created with 150 grams of NaCl in 1250mL of solution. Calculate the molarity. 7. For questions 4-7 which was the most concentrated solution? The most dilute? Calculate the molarity of each of the following solutions: (a) 2.5 mol of NaOH in L of solution (b) 1.8L of solution containing 3.3 mol KNO 3 (c) 30. g of NaOH in L of solution (d) 522 g of K 2 SO 4 in 1.5 L of solution 13

14 2. Calculate the total moles of solute in each of the following solutions: (a) 1.7 L of 0.35M NaOH (b) 50 ml of 3.3- molar KNO 3 (c) 5.0 L of 1.25 M NaOH (d) 116 ml of 1.5 M K 2 SO 4 3. Calculate the total grams of solute in each of the following solutions: (a) 1.0 L of 0.5 M CaCl 2 (b) 500 ml of 3.3- molar KNO 3 (c) 0.25 L of 1.0 M NaOH (d) 42 ml of 1.7 M K 2 SO 4 4. Find the Molarity of the following solutions: a.) 0.50 moles of sodium chloride in 0.50 liters. b.) 2.00 moles of ammonia in 0.50L solution. c.) 80.0 grams of NaOH in one liter of solution. d.) 101 grams of KNO 3 in 500. ml of solution. e.) grams of CuCl 2 dissolved in 2L of water. 5. Find the mass needed for each solution: a.) A solution of 1.00L of 2.00M NaCl b.) A solution of 0.500L of 3.00M NaOH c.) A solution of 4.00L of 0.25M CuSO 4. 5H 2 O 14

15 d.) A solution of 3.00L of 1.50M NaF e.) A solution of 1.50L of 1.50M Mg(NO 3 ) 2 Percent and Parts Per Million Percent What key words do you have to look for when answering these questions? 1. Calculate the percent by mass of 25.0 grams of NaCl in 150 grams of solution. 2. Calculate the percent by mass of 150 grams of NaCl in 1250 grams of water. Calculate the percent by mass of the following solutions: grams of solute in grams of solution grams of NaCl in grams of solution grams of KI in grams of solution grams of solute in grams of water grams of solute in grams of water grams of O 2 in 25,000,000.0 grams of water 9. What could be a better unit to express your answer to number 8? 15

16 Parts Per Million: If you are the only person who wins the Mega millions and 259 million people play, what is your part per million? 10. Calculate the parts per million of 2.0 grams of NaCl in grams of solution. 11. Calculate the parts per million of 1.50 grams of NaCl in 8000 grams of water. 12. Calculate the concentration of chlorine in ppm in a swimming pool if there is 0.02 g of chlorine in 10,000 g of pool water. 13. The health of fish depends on the amount of oxygen dissolved in the water. A dissolved oxygen (DO) concentration between 6 parts per million and 8 parts per million is best for fish health. A DO concentration greater than 1 part per million is necessary for fish survival. Fish health is also affected by water temperature and concentrations of dissolved ammonia, hydrogen sulfide, chloride compounds, and nitrate compounds. A student s fish tank contains fish, green plants, and 3800 grams of fish- tank water with 2.7 x 10-2 gram of dissolved oxygen. a.) State how an increase in the temperature of the fish- tank water affects the solubility of oxygen in the water. b.) Determine if the DO concentration in the fish tank is healthy for fish. Your response must include: a correct numerical setup to calculate the DO concentration in the water in parts per million the calculated result a statement using your calculated result that tells why the DO concentration in the water is or is not healthy for fish c.) Explain, in terms of molecular polarity, why oxygen gas has low solubility in water. Your response must include both oxygen and water. d.) Under what kind of conditions of temperature and pressure would oxygen gas be most soluble in water? e.) An aqueous solution has a concentration of 7 ppm of oxygen dissolved in grams of water. Calculate the amount of oxygen in the solution in grams. Your response must include both a correct numerical setup and the calculated result. 16

17 Section 5 Colligative Properties The addition of a nonvolatile solute to a solvent causes the boiling point of the solvent to and the freezing point of the solvent to. The greater the concentration of particles, the greater the effect. 1. What is the freezing point of water at standard pressure in degrees Celsius? 2. What is the boiling point of water at standard pressure in degrees Celsius? 3. What happens to the freezing point of water when a solute is added? Why? 4. What happens to the boiling point of water when a solute is added? Why? 5. Give an example of freezing point depression in your life. 6. Give an example of boiling point elevation in your life. 7. Which solute will raise the temperature of boiling the highest? Circle one. Explain your answer. NaCl CaCl 2 C 6 H 12 O 6 Ca 3 (PO 4 ) 2 8. Which solute will lower the temperature of freezing the least? Circle one. Explain your answer. NaCl CaCl 2 C 6 H 12 O 6 Ca 3 (PO 4 ) 2 9. Which solution has the highest boiling point? (1) 0.5 M NaCl (2) 0.5 M CaCl 2 (3) 1.0 M (NH 4 ) 3 PO 4 (4) 2.0 M CH 3 OH 10. Compared to pure water, an aqueous solution of calcium chloride has a (1) higher boiling point and higher freezing point (2) higher boiling point and lower freezing point (3) lower boiling point and higher freezing point (4) lower boiling point and lower freezing point 11. Which solution has the highest boiling point? (1) 1.0 M KNO 3 (3) 1.0 M Ca(NO 3 ) 2 (2) 2.0 M KNO 3 (4) 2.0 M Ca(NO 3 ) 2 17

18 4. Which solution has the lowest freezing point? (1) 10. g of KI dissolved in 100. g of water (2) 30. g of KI dissolved in 100. g of water (3) 20. g of KI dissolved in 200. g of water (4) 40. g of KI dissolved in 200. g of water 5. As water is added to a 0.10 M NaCl aqueous solution, the conductivity of the resulting solution (1) decreases because the concentration of ions decreases (2) decreases, but the concentration of ions remains the same (3) increases because the concentration of ions decreases (4) increases, but the concentration of ions remains the same 6. Which aqueous solution of KI freezes at the lowest temperature? (1) 1 mol of KI in 500. g of water (3) 1 mol of KI in g of water (2) 2 mol of KI in 500. g of water (4) 2 mol of KI in g of water 7. Compared to a 2.0 M aqueous solution of NaCl at 1 atmosphere, a 3.0 M aqueous solution of NaCl at 1 atmosphere has a (1) lower boiling point and a higher freezing point (2) lower boiling point and a lower freezing point (3) higher boiling point and a higher freezing point (4) higher boiling point and a lower freezing point 8. Based on Reference Table F, which of these saturated solutions has the lowest concentration of dissolved ions? (1) NaCl(aq) (2) MgCl 2 (aq) (3) NiCl 2 (aq) (4) AgCl(aq) 18

19 DIRECTIONS: On the line rewrite the question substituting one of the vocabulary words for the underlined words. Then circle the correct answer or answer on the second line. Ex: Which substance undergoes a phase change from the liquid to the gas state at 100 C? vaporization (1) CO 2 (2) H 2 (3) H 2 O (4) O 2 WORD BANK saturated solution solution dilute soluble unsaturated solution solute concentrated insoluble supersaturated solution solvent equilibrium miscible distillation solubility dissociation immiscible 1. Which is a homogeneous mixture? (1) salt (2) concrete (3) bronze (4) granite 2. What is the dissolved substance in NH 4 Cl(aq)? 3. A state of balance between dissolved and undissolved solute exists in which type of solution? (1) saturated (2) unsaturated (3) supersaturated 4. Which substance does not dissolve in water? (Hint: use Table F) (1) Ca(NO 3 ) 2 (2) CaCrO 4 (3) Ca(OH) 2 (4) CaCO 3 5. Which substance dissolves easily in water? (Hint: use Table F) (1) KCl (2) AgCl (3) PbCl 2 (4) Hg 2 Cl 2 6. As temperature increases, the number of grams dissolved in a given quantity of solvent of which substance increases? (1) HCl (2) KClO 3 (3) NH 3 (4) SO 2 7. Which pair are liquids that mix to form a solution? (1) hexane and water (2) CCl 4 and water (3) ethanol and water 8. Which is a solution that contains more solute than will normally dissolve at 70 C? (1) 10g SO 2 in 100 g of water (3) 30g KClO 3 in 100 g water (2) 10g NH 3 in 100 g of water (4) 30g NaCl in 100 g water 9 Which is a solution that contains less solute than will normally dissolve at 50 C? (1) 84g SO 2 in 100g of water (3) 84g KNO 3 in 100g water (2) 84g NH 4 Cl in 100g of water (4) 84g NaNO 3 in 100g water 10. At 25 C, which is a solution that contains relatively little dissolved solute? (1) a saturated solution of NaNO 3 (aq) (2) a saturated solution of KClO 3 19

20 Solubility Table F Solubility depends on the nature of the solution, temperature, and pressure. a. Explain why Styrofoam dissolves in acetone but not water in terms of polarity. b. Using Table F determine if the following are soluble or insoluble: 1) NaNO 3 3) Magnesium hydroxide 2) Ammonium carbonate 4) CaCO 3 c. Increases in temperature make solids dissolve but gases dissolve. d. Give examples from Table G to support your previous answer. e. Pressure only affects the gas phase. Increases in pressure the solubility of a gas. Solubility Curves Table G Very soluble solutes are found near the top of table G. Those are also more concentrated. Points that fall above a line for a solute are called supersaturated. Points below are called unsaturated. Points on the line show saturated solutions. Watch out for the amount of solvent in the question!!! a. What salt is the most concentrated at 10C? Which gas? b. How much KNO 3 dissolves at 70C in 100 grams of water? c. At what temperature will 20g of SO 2 dissolve in 100g of water? d. At what temperature will 40 grams of KNO 3 dissolve in 200g of water? e. How many grams of NaCl will dissolve in 50 grams of water at 100C? f. How many grams of KCl will precipitate out of 100 gram of water if the solution is cooled from 80C to 20C? g. What type of solution is created when 50 grams of NaNO 3 are dissolved in 50 grams of water at 20C? Concentration Table T Molarity is expressed as the moles of solute per liter of solution. It is the most common unit of concentration. Percent by mass and part per million formulas are both on Table T and both require the amount of SOLUTION on the denominator. NOT water or solvent! a. What is the molarity of 5.0 moles of NaCl in 400mL of water? b. What is the volume that would hold 2.0 moles of 3.0M KI? c. Calculate the percent by mass of a solution containing 50g of KNO 3 in 250g of water. 20

21 d. Calculate the percent by mass of a solution containing 25.0g of NaClO 3 in 250g of solution. e. Calculate the parts per million of a solution containing 5.0g of KNO 3 in 25000g of water. f. Calculate the parts per million of a solution containing 1.25g of KNO 3 in 100, 000g of solution. Colligative Properties When a solute is added to a liquid the IMF increase and the liquid refuses to change phases. Therefore the boiling point increases and the freezing point decreases. Look for the most ions to do the most damage. Watch out for covalent solutes that will remain as one particle, not ionize. a. Which solution will have the highest boiling point? 4M NaCl 2M CO 2 1M Mg 3 (PO 4 ) 2 1.5M KI b. Which solution will have the lowest freezing point? NaCl CO 2 Mg 3 (PO 4 ) 2 KI 21

22 1. An aqueous solution of sodium chloride is best classified as a A) homogeneous compound B) homogeneous mixture C) heterogeneous compound D) heterogeneous mixture 2. Which formula represents a homogeneous mixture? A) H 2 O( ) B) H 2 S(g) C) NaH(s) D) HCl(aq) 3. When sample X is passed through a filter paper a white residue, Y, remains on the paper and a clear liquid, Z, passes through. When liquid Z is vaporized, another white residue remains. Sample X is best classified as A) an element B) a compound C) a heterogeneous mixture D) a homogeneous mixture 4. A mixture of sand and table salt can be separated by filtration because the substances in the mixture differ in A) boiling point B) density at STP C) freezing point D) solubility in water 5. A bottle of rubbing alcohol contains both 2- propanol and water. These liquids can be separated by the process of distillation because the 2- propanol and water A) have combined chemically and retain their different boiling points B) have combined chemically and have the same boiling point C) have combined physically and retain their different boiling points D) have combined physically and have the same boiling point 6. Given the diagram representing a process being used to separate the colored dyes in food coloring: Which process is represented by this diagram? A) chromatography B) electrolysis C) distillation D) titration 7. Which compound is insoluble in water? A) calcium bromide B) potassium bromide C) silver bromide D) sodium bromide 22

23 8. Which compound is insoluble in water? A) BaSO 4 B) CaCrO 4 C) KClO 3 D) Na 2 S 9. Which ion, when combined with chloride ions, Cl, forms an insoluble substance in water? A) Fe 2+ B) Mg 2+ C) Pb 2+ D) Zn Based on Reference Table F, which of these saturated solutions has the lowest concentration of dissolved ions? A) NaCl(aq) B) MgCl 2 (aq) C) NiCl 2 (aq) D) AgCl(aq) 11. According to Reference Table F, which substance is most soluble? A) AgI B) CaSO 4 C) PbCl 2 D) (NH 4 ) 2 CO In an aqueous solution of potassium chloride, the solute is A) Cl B) K C) KCl D) H 2 O 13. Which compound is most soluble in water? A) silver acetate B) silver chloride C) silver hydroxide D) none, all are insoluble 14. Under which conditions of temperature and pressure is a gas most soluble in water? A) high temperature and low pressure B) high temperature and high pressure C) low temperature and low pressure D) low temperature and high pressure 15. At which temperature can water contain the most dissolved oxygen at a pressure of 1 atmosphere? A) 10.ºC B) 20.ºC C) 30.ºC D) 40.ºC 16. A change in pressure would have the greatest effect on the solubility of a A) solid in a liquid B) gas in a liquid C) liquid in a liquid D) liquid in a solid 17. Which change will cause the solubility of KNO 3 (s) to increase? A) decreasing the pressure C) increasing the pressure B) decreasing the temperature D) increasing the temperature 18. At standard pressure, which substance becomes less soluble in water as temperature increases from 10. C to 80. C? A) HCl B) KCl C) NaCl D) NH 4 Cl 19. An unsaturated aqueous solution of NH3 is at 90 C in 100. grams of water. According to Reference Table G, how many grams of NH 3 could this unsaturated solution contain? 23

24 A) 5 g B) 10. g C) 15 g D) 20. G 20. According to your Reference Tables, which substance forms an unsaturated solution when 80 grams of the substance is dissolved in 100 grams of H2O at 10 C? A) KI B) KNO 3 C) NaNO 3 D) NaCl 21. Solubility data for four different salts in water at 60 C are shown in the table below. Which salt is most soluble at 60 C? A) A B) B C) C D) D 22. According to Reference Table G, how many grams of KNO 3 would be needed to saturate 200 grams of water at 70ºC? A) 43 g B) 86 g C) 134 g D) 268 g 23. According to Reference Table G, how does a decrease in temperature from 40 C to 20 C affect the solubility of NH 3 and KCl? A) The solubility of NH3 decreases, and the solubility of KCl decreases. B) The solubility of NH3 decreases, and the solubility of KCl increases. C) The solubility of NH3 increases, and the solubility of KCl decreases. D) The solubility of NH3 increases, and the solubility of KCl increases. 24. As the temperature increases from 0ºC to 25ºC the amount of NH 3 that can be dissolved in 100 grams of water A) decreases by 10 grams B) decreases by 40 grams C) increases by 10 grams D) increases by 40 grams 25. According to Reference Table G, a temperature change from 10 C to 30 C would have the least effect on the solubility of A) NaCl B) KClO3 C) NH3 D) SO2 26. The graph below represents four solubility curves. Which curve best represents the solubility of a gas in water? A) A B) B C) C D) D 24

25 27. When 5 grams of KCl are dissolved in 50. grams of water at 25 C, the resulting mixture can be described as A) heterogeneous and unsaturated B) heterogeneous and supersaturated C) homogeneous and unsaturated D) homogeneous and supersaturated 28. A solution contains 130 grams of KNO 3 dissolved in 100 grams of water. When 3 more grams of KNO 3 is added, none of it dissolves, nor do any additional crystals appear. The temperature of the solution is closest to A) 65ºC B) 68ºC C) 70ºC D) 72ºC 29. A solution containing 90. grams of KNO 3 per 100. grams of H2O at 50. C is considered to be A) dilute and unsaturated B) dilute and supersaturated C) concentrated and unsaturated D) concentrated and supersaturated 30. A solution contains 90 grams of a salt dissolved in 100 grams of water at 40ºC. The solution could be an unsaturated solution of A) KCl B) KNO 3 C) NaCl D) NaNO 3 B) 31. According to Reference Table G, how many grams of NH 4 Cl must be dissolved in 100 grams of H2O at 70ºC to reach solution equilibrium? A) 52 g B) 56 g C) 62 g D) 86 g 32. What is the total number of grams of potassium chloride needed to saturate exactly 300 grams of water at 10 C? A) 60 B) 70 C) 80 D) A solution containing 55 grams of NH 4 Cl in 100. grams of water is saturated at a temperature of A) 47ºC B) 57ºC C) 67ºC D) 77ºC 34. The molarity of an aqueous solution of NaCl is defined as the A) grams of NaCl per liter of water B) grams of NaCl per liter of solution C) moles of NaCl per liter of water D) moles of NaCl per liter of solution 35. Which unit can be used to express solution concentration? A) J/mol B) L/mol C) mol/l D) mol/s 36. How many moles of solute are contained in 200 milliliters of a 1 M solution? A) 1 B) 0.2 C) 0.8 D)

26 37. Which preparation produces a 2.0 M solution of C 6 H 12 O 6? [molecular mass = 180.0] A) 90.0 g of C 6 H 12 O 6 dissolved in ml of solution B) 90.0 g of C 6 H 12 O 6 dissolved in ml of solution C) g of C 6 H 12 O 6 dissolved in ml of solution D) g of C 6 H 12 O 6 dissolved in ml of solution 38. What is the total number of moles of solute in 2.0 liters of 3.0 M NaOH? A) 1.0 mole B) 2.0 moles C) 3.0 moles D) 6.0 moles 39. What is the total number of grams of HI in liter of 1.00 M HI? A) 1.00 g B) g C) 64.0 g D) 128 g 40. What is the total number of grams of NaOH (formula mass = 40.) needed to make 1.0 liter of a 0.20 M solution? A) 20. g B) 2.0 g C) 80. g D) 8.0 g 41. What is the molarity of an H2SO4 solution if 0.25 liter of the solution contains 0.75 mole of H2SO4? A) 0.33 M B) 0.75 M C) 3.0 M D) 6.0 M 42. When 20. milliliters of 1.0 M HCl is diluted to a total volume of 60. milliliters, the concentration of the resulting solution is A) 1.0 M B) 0.50 M C) 0.33 M D) 0.25 M 43. If 100. milliliters of a 1.0- molar NaCl solution is evaporated to 25 milliliters, what will be the concentration of the resulting NaCl solution? A) 0.25 M B) 2.0 M C) 0.50 M D) 4.0 M 44. Which solution contains exactly 0.50 mole of H 2 SO 4? A) 1.0 L of a 1.0 M solution B) 2.0 L of a 1.0 M solution C) 1.0 L of a 0.50 M solution D) 2.0 L of a 0.50 M solution 45. What is the molarity of a solution that contains 30. grams of NaOH in 500. milliliters of solution? A) 0.75 M B) 1.3 M C) 1.5 M D) 2.6 M 46. What is the molarity of a solution of KNO 3 (molecular mass = 101) that contains 404 grams of KNO 3 in 2.00 liters of solution? A) 1.00 B) 2.00 C) D)

27 47. Which type of concentration is calculated when the grams of solute is divided by the grams of the solution, and the result is multiplied by 1,000,000? A) molarity B) parts per million C) percent by mass D) percent by volume 48. Which unit can be used to express the concentration of a solution? A) L/s B) J/g C) ppm D) kpa 49. What is the concentration of a solution, in parts per million, if 0.02 gram of Na 3 PO 4 is dissolved in 1000 grams of water? A) 20 ppm B) 2 ppm C) 0.2 ppm D) 0.02 ppm 50. What is the concentration expressed in parts per million of a solution containing 15.0 grams of KNO 3 in 65.0 grams of H2O? A) ppm B) ppm C) ppm D) ppm 51. What is the total mass of solute in grams of a solution having a concentration of 5 parts per million? A) g B) 0.05g C) 0.5 g D) 5g 52. Compared to pure water, an aqueous solution of calcium chloride has a A) higher boiling point and higher freezing point B) higher boiling point and lower freezing point C) lower boiling point and higher freezing point D) lower boiling point and lower freezing point 53. Which concentration of a solution of CH 3 OH in water has the lowest freezing point? A) 0.1 M B) 0.01 M C) M D) M 54. A 1 kilogram sample of water will have the highest freezing point when it contains A) dissolved particles B) dissolved particles C) dissolved particles D) dissolved particles 55. Which solution will freeze at the lowest temperature? A) 1 mole of sugar in 500 g of water B) 1 mole of sugar in 1,000 g of water C) 2 moles of sugar in 500 g of water D) 2 moles of sugar in 1,000 g of water 27

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