Solutions for 6.1A Extra Practice Questions: Properties of Solutions

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1 6.1B Solutions for 6.1A Extra Practice Questions: Properties of Solutions ist some properties that could be used to construct dianostic tests to identify the type of solute in each of the followin solutions. 1. an aqueous solution of a molecular substance does not conduct electricity has no effect on the color of litmus paper 2. an aqueous solution of a neutral ionic compound has no effect on the color of litmus paper 3. an aqueous solution of an acid turns blue litmus paper red 4. an aqueous solution of a base turns red litmus paper blue 5. Identify, by name, the solute and solvent in each of the followin solutions. (a) NaOH (b) CO 2 solute: sodium hydroxide solute: carbon dioxide solvent: water solvent: water (c) Br 2(al) (d) M(HCO 3 ) 2 solute: bromine solute: manesium hydroen carbonate solvent: alcohol solvent: water 6. Question Which of the solutions labelled A, B, C, and D contain HCl, NaClO4, NH 2 OH, NaOH? Experimental Desin (a) Write an experimental desin to answer the question. Identify all variables and controls. Each solution is tested with a conductivity apparatus and with litmus paper. The inpendent variable is the solution tested; the dependent variable is the dianostic test; and the controlled variables are the concentration and temperature of the solution. Pure water is used as a control. Materials (b) ist all materials required for this investiation. lab apron well plate or small beaker safety lasses conductivity tester solutions A, B, C, D red and blue litmus paper distilled water bottle Procedure (c) Write a list steps necessary to answer the question. (There are no special disposal requirements.) 1. Place about 1 m of pure water in a clean well. 2. Test and record the conductivity of the water. 3. Test with red and blue litmus, and record any color chane. 4. Rinse and clean the conductivity leads. 5. Repeat steps 1-4 usin the iven solutions in place of water. 6. All solutions are disposed in the sink and litmus paper into the waste basket. 3-6 Unit 3 ab and Study Masters Copyriht 2002 Nelson Thomson earnin

2 6.2B Solutions for 6.2A Extra Practice Questions: Explainin Solutions 1. The followin substances are common chemicals: butane, C 4 H 10(), (lihters); ethanol, C 2 H 5 OH (l), (alcoholic drinks); dichloromethane, CH 2 Cl 2(l), (solvent in correction fluid) (a) Classify the type(s) of intermolecular forces present amon molecules of each of these substances. butane, ondon dispersion forces; low ethanol, ondon dispersion, dipole-dipole, hydroen-bondin forces; hih dichloromethane, ondon dispersion and dipole-dipole; moderate (b) Predict the solubility (low, moderate, or hih) of each substance in water. (See above) 2. Why do ionic compounds have a hih solubility in water, compared to their solubility in any other solvent? Ionic compounds contain electrically-chared ions. The very polar water molecules are able to form many attractions to both the positive and neative ions. 3. ist the three features of a water molecule that make water the best solvent. Water molecules have a small size, are hihly polar, and have a considerable capacity for hydroen bondin. 4. For each of the followin substances, write the chemical formula includin pure state of matter at SATP, predict the solubility (low/hih) in water, and if appropriate write a balanced dissociation equation. (a) silver sulfide A 2 S (s) low (b) ammonium borate (NH 4 ) 3 BO 3(s) hih (NH 4 ) 3 BO 3(s) 3 NH BO 3 3- (c) copper(ii) nitrate trihydrate Cu(NO 3 ) 2 3H 2 hih Cu(NO 3 ) 2 3H 2 Cu NO H 2 O (l) (d) lucose, C 6 H 12 O 6(s) hih 3-12 Unit 3 ab and Study Masters Copyriht 2002 Nelson Thomson earnin

3 6.3B Solutions for 6.3A Extra Practice Questions: Concentration Use concentration as a conversion factor to calculate the quantity requested in each question below. Communicate your problem-solvin approach, includin units and correct certainty. 1. Cow s milk contains 4.5 of lactose per 100 m of milk. What mass of lactose is present in 250 m (one lass) of milk? 4.5 m lactose 250 m m 2. A 10% W/V salt solution is used for makin pickles. What mass of salt is present in 750 m of this solution? 10 m NaCl 750 m m 3. A 250 m measurin cup of cleanin solution contains 1.2 mol of dissolved ammonia. What is the molar concentration of this solution? C NH3 1. 2mo l 4.8 mol/ Fish require a concentration of about 4.5 ppm (4.5 m/) of dissolved oxyen in water. What volume of water would contain 100 m of oxyen? v 100 m 1 H2O m 5. What volume of concentrated, 14.6 mol/ phosphoric acid would contain 2.00 mol of solute? 1 v H3PO mol mol 6. What mass of table salt is needed to prepare 1.20 of 5.20 mol/ solution? n NaCl mol 6.24 m NaCl What is the molar concentration of zinc nitrate if 94.2 of solute is dissolved to make 2.00 of solution? n Zn(NO3) mol C Zn(NO3) mol mol / Unit 3 ab and Study Masters Copyriht 2002 Nelson Thomson earnin

4 6.5D Solutions for 6.5C Extra Practice Questions: Dilution In the followin questions, concentrated refers to the concentration of the most common commercial reaent as listed in the table of Concentrated Reaents inside the back cover of the textbook. 1. An ammonia solution is made by dilutin 150 m of the concentrated commercial reaent until the final volume reaches 1000 m. What is the final molar concentration? 150 m 14.8 mol/ 1000 m 2.22 mol/ 2. What volume of a 500 ppm reaent solution is required to prepare a 2.5 solution with a 100 ppm concentration? 500 ppm ppm A 500 m bottle of concentrated acetic acid is diluted to make a 5.0% solution. Find the volume of diluted solution that is prepared. 500 m 99.5% 5.0% v f In a chemical analysis, a 25.0 m sample was diluted to m and analyzed. If the diluted solution had a molar concentration of mol/, what was the molar concentration of the oriinal sample? 25.0 m m mol/ 2.16 mol/ 5. If a 355 m can of soda pop is diluted to a final volume of 1.00, what can be said quantitatively about the concentration of the diluted solution as compared with the oriinal solution? The diluted solution has a concentration times or 35.5% of the oriinal solution Unit 3 ab and Study Masters Copyriht 2002 Nelson Thomson earnin

5 6.5F Solutions for 6.5E Extra Practice Questions: Solution Preparation Communicate your problem-solvin approach when answerin the questions below. 1. Calculate the molar concentration of a solution made by dissolvin 20.0 of sodium hydroxide to make 300 m of solution. n NaOH mol C NaOH mol 1.67 mol/ Pure sodium thiosulfate-5-water, Na 2 S 2 O 3 5H 2, is used to make 250 m of 20.0 mmol/ solution. Find the mass of solute required. n Na2 S 2 O 3 5H 2 O mmol 5.00 mmol m Na2 S 2 O 3 5H 2 O 5.00 mmol What mass of copper(ii) nitrate will be required to prepare 10.0 of mol/ solution? n Cu(NO3 ) mol 1.00 mol 2 m Cu(NO3 ) 1.00 mol What volume of 75 mmol/ solution can be prepared from 10 of sodium carbonate? n Na2 CO mmol v Na2 CO 94 mmol mmol 5. Determine the volume of concentrated hydrochloric acid required to prepare 10.0 of a mol/ solution mol mol What volume of concentrated ammonia is required to prepare 2.0 of a 1.0 mol/ solution? mol mol Unit 3 ab and Study Masters Copyriht 2002 Nelson Thomson earnin