k. Solutions Packet Test 2

Unit 11

SolutionsIntroduction: A solution is a homogenous mixture. Perhaps the best way to get an idea just how common solutions are is to go grocery shopping. There you will see virtually every type of solution, in all sorts of colors and types. This unit is primarily a roll-up-your sleeves and learn how to do things unit. Learn how to make a 25% (v/v) fruit juice solution. Dilute a chocolate solution from 20% to 8%. Find out why they salt the roads in the winter and just how much of an effect it has. How do we make and modify solutions?

Schedule: Day 1 Learn How to make rock candy; introduction to solutions Measure density of tiny objects Theory of making, diluting, and concentrating solutions How to make and dilute solutions Why they put salt on the roads Put it all together activity Rock candy lab Intro to solutions powerpoint Flink lab Solution concentration powerpoint Making solutions activity Colligative properties Test review Solutions test homework Ws 11.1: introduction to solutions Rock candy questions Complete lab ws ws Study for test Read next unit introduction.

2 3 4 5 6 7

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Name__________________________ Period______________ Lab11.1: Rock Candy Lab Rock Candy Lab Introduction: Have you ever noticed on television how clean the scientists labs are? How carefully they work with their solutions, their little pipettes, or even with their cadavers? Usually Hollywood hopelessly botches any attempt to portray scientists, but in this case they got it right. Good science requires pure chemicals. And to this day one of the best ways to prepare a pure solid sample is by recyrstallization- the process of isolating pure crystals from a solid/liquid solution. In this experiment you will make rock candy at home and bring it in to share with your classmates. This is an excellent example of recrystallization in action. Safety Notice: Since no food is allowed in the lab, this experiment must be performed at home. Rock Candy A video can be seen here at http://chemistry.learnhub.com/lesson/9991-rock-candy-video Prep: 15 min., Cook: 20 min., Stand: 14 days. Ingredients 1 Pie tin A clear cup 6 cups of sugar 4 wood skewers Cardboard to cover cup Masking tape

Recipe 2. Bring 2 cups of water to a boil, then add 6 cups of sugar and stir until dissolved. Measure carefully, as our experiments suggest that as little a measurement off by as little as 5% can make a huge difference in crystallization time. Add any food-grade additives you like: food coloring, cinnamon oil, vanilla, etc. 4. Fill a clear plastic cup with the hot sugar solution, cover with the cardboard, and tape shut. Stick skewers in, not touching the bottom. Let stand 10 to 14 days.

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Name_______________________________ period_________________ lab 1.1rockcandy Use any reliable sources necessary on the web to answer the following questions: 1. Draw the chemical structure of glucose, fructose, and sucrose, with their chemical formula below each structure.

glucose: formula:___________

fructose: formula:________

sucrose: formula:___________

2. Which of the above sugars is table sugar? Glucose, fructose, of sucrose?

2. It is said that a crystal resembles the structure of the molecule it is formed from. The hexagonal quartz crystals from SiO2 are an example. Since we started from sugar crystals, dissolved them in water, then let them reform slowly, the process is known as recrystallization. Based on the chemical structure of table sugar, draw a prediction of what your crystals will look like.

Predicted close-up view of a sugar crystal 4. Explain in you own words why it may a good idea to coat your string in sugar to aid in recyrstallization. The principle is known as nucleation, but please explain it without sounding like a science geek.

5. Why do we use so much sugar and so little water in this recipe? The principle is known as supersaturation, but explain it in your own words without sounding like a science teacher.

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Name___________________________ Period____________ Rock Candy Lab Notebook

rockcandylabnotebook

Please make daily notes as you observe your rock candy experiment progressing. You should include observations, comparisons to other experiments, and document any changes, such as heating, adding ventilation, or any substances added to the solution. Date Observations Changes made to experiment Comparison to others

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3. How does it happen?

4. How does it NOT happen?

5. Will heating or pressure help?

6. Make Crystals

SolutionsWhat are they? Homogeneous mixtures Only one thing visible Where are they? Everywhere!

7. Types 8. Measuring

2. What are they?

What is in a solution?

9. Making them 10. Using them

Solvent: dissolvermouthwash water granite bronze

Solute(s): dissolvedyes no no yesChemadventure Chapter 11: Solutions

1. Where are they?

Is it a solution?

1



A molecular view of dissolving:


6. Make Crystals7. Types 8. Measuring

2. What are they?

Fully dissolved salt water Partly dissolved


Solvation:Not a salt (ex: sugar)

1. Where are they?

= solvent surrounding the solute2

Electrolyte: Salt. Non-Electrolyte:

Chemadventure Chapter 11: Solutions

5





Name Methanol Ethanol Propanol Butanol

Why dont oil and water mix? Soluble in Formula water?

Solubility

Greasier

2. What are they?

CH3OH CH3CH2OHCH3CH2CH2OHCH3CH2CH2CH2OH

yes yes Yes No!watery


1. Where are they?

Greasy Rule of thumb:4. How does it NOT happen?

like dissolves likeChemadventure Chapter 11: Solutions

3




Heating Solutions A solubility surprise:Heating makes Most solids More Soluble Most gases Less Soluble

2. What are they?


1. Where are they?

Global implications

4Chemadventure Chapter 11: Solutions

6



Is there a way to increase the solubility of ANY solution?



Yes: Henrys LawS1/P1 = S2/P2

Solubility is proportional to pressure

S~P

2. What are they?


1. Where are they?

If sol. Is 1g/L at 1 atm, it will be 2 ______g/L at 2 atm Everyone: if solubility is 3.45 g/L at 5.6 atm, what is the solubility at 1 atm?3.45/5.61 = S2/1(Henrys Law Worksheet)Chemadventure Chapter 11: Solutions

S2 = 0.614 g/L5



The process:

Watch a video online here or play the flv file here or the avi file here

How to make crystals:recrystallization supersaturation



The principle:

2. What are they?

1. Make a hot supersaturated solution and cool

saturated


2.

Or evaporate Or Reduce pressure

1. Where are they?

The process of forming the very first crystal during crystallization is calledFun nucleation video here

nucleation6Chemadventure Chapter 11: Solutions

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SolutionsType Gas-gas Gas-liquid Liq-Liq Solid-liq Solid-solid Ex. Air Soda Vinegar Ocean Fillings Solvent N2 H2O H2O H2O Ag solute O2 CO2 salts Hg7Chemadventure Chapter 11: Solutions

2. What are they?


Acetic acid

1. Where are they?



Concentration



2. What are they?

10 g NaCl 90 g H2O

% by mass (% m/m)10% NaCl by Mass

Mass solute x 100 Mass of solution Volume of solute x 100 Volume of solution Moles of solute Liter of solution Moles of solute Kg of solvent Moles of soluteChemadventure Chapter 11: Solutions

10 mL juice % by volume (% v/v) 90 mL H2O 10% NaCl by Volume 58.5 g NaCl 1L solution 58.5 g NaCl 1 kg water 58.5 g NaCl 162 g H2O


Molarity (M)1M NaCl

1. Where are they?

Molality (M) 1m NaCl L1 only Mole Fraction (X)XNaCl = 0.1L1 only

Moles solution

8

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Molarity Examples


6. Make Crystals


1. Where are they?

You have a 100.5 mL solution containing 5.1 g glucose (molar mass = 180.16 g/mol). What is the molarity of that solution? Solution Molarity = moles of solute/L of solution Moles solute = 5.1 g glucose x 1 mole glucose/180.16 g glucose = 0.0283 moles glucose L of solution = 100.5 mL x 1L/1000 mL = 0.1005 L solution Molarity = 0.0283 moles/0.1005 L solution = 0.282M Molarity ws9Chemadventure Chapter 11: Solutions

2. What are they?




Another example



Make 100 mL of a 1M NaOH solution1 mole NaOH 40 g NaOH x x 0.1 liter solution 4 g NaOH liter solution mole NaOHTake 4 g NaOH; add water til 100 mL.

2. What are they?


1. Where are they?

10Chemadventure Chapter 11: Solutions

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As solvent increases, concentration

Dilution


6. Make Crystals


decreases

2. What are they?

Concentration may be Molarity, % v/v, % mass How can I dilute 53.4 mL of a 1.50M soln of NaCl to make it a 0.800M solution? Easy: C1V1 = C2V2 (1.50mol/L)(53.4mL)= (0.800mol/L)(V2) V2 = 100. mL (dilute to 100 mL to get 100 mL of a 0.8M soln)5. Will heating or pressure help?

C1 V1 = C2 V2


1. Where are they?

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How do solutes affect boiling and freezing point?

L2: concepts only. (L1 all)

Colligative Properties


2. What are they?

collective


1. Where are they?

Solutes elevate the boiling point Solutes lower the freezing point (road salt)12Chemadventure Chapter 11: Solutions

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Solutes elevate boiling point5. Will heating or pressure help?


L1 only

Fewer solvent molecules on surfacex

2. What are they?

pm

Particle molality# of ions

BP elevation constant molality

Sugar = 1 NaCl = 2 CaCl2 = 3


= moles solute/Kg solventWhat is the boiling point of a 2.75m aqueous NaCl solution?Tb =Kbm x pm Particle molality = 2 (easy to forget) = (0.512)(2.75 x 2)= 10.22 oC BP = 102.82 oCChemadventure Chapter 11: Solutions

1. Where are they?

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Interfere with crystal formation L1 only Particle molalityTf = Kfmx

Solutes lower freezing pointpm


6. Make Crystals


2. What are they?

FP depression

constant molality = moles solute/Kg solventWhat is the freezing point of a 2.75m aqueous NaCl solution?Tf =Kfm x pm Particle molality = 2 (easy to forget) = (1.86)(2.75 x 2)= 10.22 oC FP = -10.22 oC 14

Sugar = 1 NaCl = 2 CaCl2 = 3


1. Where are they?

Next: Energy


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Name: _______________________________ Date: _______ Period: ______ Plastic Bead Density Activity

Lab11.2

In this demonstration we will flink a plastic bead using sugar and water to determine the density of the solution. We will then use our data to determine the concentration of the solution by mass, volume, and molarity. Useful Formulas: Density = mass/volume % by Mass = (mass solute/mass solution) x 100 % by volume = (volume solute/volume solution) x 100 Molarity = M = moles solute/liters solution

Procedure: Using a test tube, water, and sugar, Make your bead hover. Keep track of exactly how many mL of water and how many grams of sugar are in your solution.1. Data Volume of water: _______mL Mass of water:__________g (same number since density of water is 1 g/mL) Volume of sugar: ________g Mass of sugar = _____mL (sucrose density = 1.59 g/mL). Show your calculation below: Total volume of solution: _________mL (measure using a graduated cylinder. Total mass of solution:___________g (add up mass of water and mass of sugar) 2. Calculations. Use the formulas on the first page for your calculations. You must show your work for credit. 1. Determine the density of the bead.

2. Determine the % sugar in the solution by volume.

3. Determine the % sugar in the solution by mass.

4. Determine the molarity of the sugar (C12H22O11) solution. Note that 1 mole of sugar is 338 grams

Summarize your results here for credit: Results: 1. Density of bead: ___________2. % sugar in solution by volume:_________3. % Sugar in solution by mass:___________4. Molarity of sugar solution:__________

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Name_________________________ Period________________ Talking about Solutions

ws 11.1

For some of us, when we think of a chemist we imagine some person in a lab coat mixing chemicals together. That person is preparing a solution, which is what this unit is all about. Read the paragraphs below and then use your newfound knowledge to answer the questions that follow. A solution is a homogeneous mixture, which means that only one thing is visible in the solution. The substance that is dissolved is the solute, and the substance that does the dissolving is the solvent. On a molecular scale dissolving involves the solvent surrounding the solute, and if they are salts they are divided into their ionic components- this process is known as solvation. Solutes that are salts are known as electrolytes. If the solutes are not ionic, like sugar for example, they are non-electrolytes. In general if the solute has a chemical structure similar to the solvent, it will dissolve. For this concept (solubility) it is said that like dissolves like. In the organic world one can identify, for example, greasy (hydrocarbon chains), watery (OH groups), and brick-like (alternating double-bonded rings like Greasy: will dissolve in benzene) groups. A brick: hard to

HO

greasy solvents

It has often been observed that one can, at least temporarily, can handle. For example, a maximum of 35.9 grams of table salt (NaCl) is soluble in 100 mL of water at 25 O C: this is a saturated solution; it has all the salt it can handle. But if you add it slowly you can get 40 or even 45 grams of salt to dissolve in water. It is now supersaturated, and the extra salt will precipitate or crash out of solution by doing almost anything- it is ultra-sensitive. Its almost like the first molecule of salt needs to crystallize, but none of the moleculesregion volunteering. That first watery are crystal forming from a supersaturated solution is known as nucleation, and there are two ways to get a volunteer. The classic way is to add a tiny amount of solid salt (known as a seed crystal)kind of like adding a volunteer; this is called heterogeneous nucleation. The second way is to just bump the solution, or keep waiting, and finally a molecule decides to volunteer on its own. This is hard to replicate because it is so sensitive, and is known as homogeneous nucleation. Finally, when the solute precipitates slowly this is known as recrystallization, and is a great way to make super-pure crystals. One can improve the solubility of a substance by changing the pressure or temperature of the solution. For solid solutes in a liquid solution (like salt in water), solubility usually, but doesnt always increase with temperature. For example, more sugar will dissolve in water if you heat it up. Now consider soda, where heating soda makes it go flat. So for gases dissolved in liquids, solubility decreases as temperature increases. Globally, since more oxygen will dissolve in cold water than hot, this explains why the nutrient-rich seas are near the poles. Finally, solubility increases with pressureby selling soda in pressurized containers more carbon dioxide can be added to soda, giving it a better taste. This is known as Henrys Law, which is our next topic. 13

watery: will dissolve in dissolve in anything. watery solvents (like water) add more solute to a solvent than it

Name______________________________ Period__________ WS 11.1 Intro to solutions Please read the previous page completely before answering the questions below Use the word back to define or answer the following questions Word Bank- These may not be used at all, or may be used more than once _____A. A homogeneous mixture is a _______ _____B. Excessive solute temporarily dissolved in a solvent results in _________ _____C. Adding a seed crystal results in ___________ nucleation _____D. An ionic solute in an _________ _____E. A solution only has one thing visible- it is __________ _____F. A non-ionic solute is a ____________ _____G. The dissolvER in a solution is the _______ _____H. Crystal formation with no additive is ___ nucleation. _____I. The substance that gets dissolvED in a solution is the ___. _____J. Solvent molecules surrounding the solute molecules is ____. _____K. When the first solute molecule precipitates is _____. _____L. A solution that has all the solute it can dissolve is _____. _____M. Add _______a to promote heterogeneous nucleation. _____N. dissolving a solute then crystallizing again is ______. Predict if the following solutions are soluble (S) or insoluble (I). Solute Solvent 14. methanol CH2OH Water (HOH) ethanol (CH3CH2OH) 15. naphthalene 16. methane (CH4) Gasoline (CH3CH2CH2CH2CH2CH3) water 1. Solution 2. Homogeneous (use twice) 3. Solvent 4. Solute 5. Solvation 6. Electrolyte 7. non-electrolyte 8. supersaturation 9. nucleation 10. heterogeneous 11. recrystallization 12. seed crystal 13. saturated

Soluble (S) or insoluble (I)?

17. hexanol (CH3CH2CH2CH2CH2CH2OH) 18. Describe three ways to increase the solubility of a solute in a solution.

19. Why do whales do most of their eating in the nutrient-rich waters near the poles?

20. What is Henrys Law? 14

Name: ______________________________ Period_________ Henrys Law

WS11.2

A sure-fire way to increase the solubility of any solute is to pressurize the solution. You see this in action every time you open a can or bottle of soda: as soon as you open it the pressure in the container goes down, so the solubility of the carbon dioxide in water goes down, and it precipitates as bubbles. Put another way, soda makers can dissolve more carbon dioxide in their soda by pressurizing the solution. Henrys Law states this fact -that solubility is proportional to temperature mathematically. The formula is:

S1 S2 P P 1 2Where S1 and S2 are the initial and final solubilities, and the Ps are for pressure. Since the units cancel and are always positive, any consistent units can be used. Example: Id like to make some super-carbonated soda. The solubility of CO2 in water at room temperature is 3.3 g CO2 per liter of solution at STP (273K, 1 atm). Id like to triple that. How much pressure should I apply? Solution: This one you might be able to do in your head. To triple the solubility we need to triple the pressure- from 1 atmosphere to 3 atmospheres:

S1 S2 3.3 g /L 9.9 g/L (1 atm)(9.9 g/L) ; ; x= 3 atm P P 1 atm x (3.3 g/L) 1 21. 0.85 g of a gas at 4.0 atm of pressure dissolves in 1.0 L of water at 298 K, how much will dissolve in 1.0 L of water at 1.0 atm of pressure at the same temperature?

2. 1.8 g of a gas at 2.5 atm of pressure dissolves in 2.0 L of Carbon Tetrachloride at 420 K. What pressure would the solution have to be at if 4.7 g of the same gas is dissolved at the same volume and temperature?

3. 4.28 g of a gas at 1.7 atm of pressure dissolves in 2.3 L of water at 527 K, how much will dissolve in 1.0 L of water at 1.0 atm of pressure at the same temperature?

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Name_________________________ Period________________ Solution Making Activity

ws 11.3

People are making solutions all the time. A cup of tea contains about 1% caffeine by mass, for example. In this activity you will prepare and dilute several solutions. The following formulas will be helpful:

C1V1 = C2V2 Where C = concentration. Usually in moles/liter, it can also be percent by mass, or percent by volume V = volume in liters Part one: Preparing solutions Example Deliver 250 mL of a 10% v/v fruit juice solution to your instructor. Provide your calculation and recipe below. Solution: ten percent of the solution is juice so Calculation Recipe (.1)(250 mL) = 25 mL juice Dilute 25 mL of fruit juice to 250 mL with water. Deliver each of the following solutions up to your instructor. 1. Deliver 25 mL of a 5% v/v fruit juice solution to your instructor. Provide your calculation and recipe below. Calculation Recipe

mass solute x 100 mass solution volume solute Percent solution by volume x 100 volume solution moles of solute Molarity = M = Liters of solution Percent solution by mass Dilution formula:

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2. Deliver 20 mL of a 31% v/v fruit juice solution to your instructor. Provide your calculation and recipe below. Calculation Recipe

Part two: Diluting solutions Example: Take ten mL of your 5% fruit juice solution from #1, dilute it to 3%, and deliver it to your instructor. Provide your calculation and recipe below. Solution: use the dilution formula to find the total volume of your diluted solution. Calculation Recipe C1V1 = C2V2 Dilute ten mL of your solution from #1 to 16.7 (5)(10) = (3)(x); x = 16.7 mL mL 4. Take 5 mL of your 31% fruit juice solution from #2, dilute it to 23%, and deliver it to your instructor. Provide your calculation and recipe below. Calculation Recipe

Part three: Preparing solutions based on Molarity (L1 only). Example: Prepare 80 mL of an aqueous 0.5M NaCl solution. Provide your calculation and recipe below. Solution: use the Molarity formula, molar mass of NaCl, and volume of your solution to find out how many grams of salt you need. Calculation Recipe Dilute 1.6 g NaCl to 40 g NaCl 0.5 moles NaCl x x 0.08 Liters solution = 1.6 grams NaCl 80 mL with water. Liter of solution mole NaCl

5. Deliver 74 mL of a 0.7M NaCl solution to your instructor. Provide your calculation and recipe below. Calculation Recipe

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Name________________________ Period_________________ Making Solutions Calculations

WS 11.4 making solutions

An essential skill for any scientist is the ability to make and modify solutions. To be sure your can calculate how to prepare solutions, Use the formulas below to answer each question. If you have any questions refer to worksheet 11.3 The following formulas will be helpful:

C1V1 = C2V2 Where C = concentration. Usually in moles/liter, it can also be percent by mass, or percent by volume V = volume in liters Type 1: Percent by mass and volume 1. How would you prepare 2 liters of a 35% m/m apple juice solution? Provide your calculation and recipe below. Calculation

mass solute x 100 mass solution volume solute Percent solution by volume x 100 volume solution moles of solute Molarity = M = Liters of solution Percent solution by mass Dilution formula:

Recipe

2. How would you prepare 5 mL of an aqueous 31%v/v NaCl solution? Note that the density of NaCl is 2.16 g/mL? Provide your calculation and recipe below. Calculation Recipe

3. How would you prepare a 10% fruit juice solution from concentrate for any volume? Calculation Recipe

Type 2: Concentration and dilution 4. How would you dilute 2 liters of a 35% m/m apple juice solution down to 19%? Provide your calculation and recipe below. Calculation Recipe

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5. How would you concentrate 1 gallon of a 10%v/v chocolate milk solution up to 24%? Provide your calculation and recipe below. Calculation Recipe

Type 3: Molarity, molality, and mole fraction (L1 only) 6. How would you dilute prepare 50 liters of 2M NaOH solution? Calculation

Recipe

7. How would you prepare 3 liters of a 4m vinegar (C2H4O2 in water) solution? Provide your calculation and recipe below. Calculation Recipe

8. Bonus Question: Provide a recipe for preparing 200 mL of a 25% v/v NaCl solution, then concentrating it to 12M. Calculation Recipe

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Name: ______________________________ Period: _____ Colligative Properties WS I L1 only

WS11.4

Directions: For each of the following questions use the appropriate relationship or equation to solve the problem. 1. What are the boiling point and freezing point of a 0.625m Aqueous solution of any nonvolatile, nonelectrolyte solute?

2. What are the boiling point and freezing point of a 0.40m solution of sucrose in ethanol?

3. A lab technician determines the boiling point elevation of an aqueous solution of a nonvolatile, nonelectrolyte to be 1.12C. What is the solutions molality?

4. A student dissolves 0.500 mol of a nonvolatile, nonelectrolyte solute in one kilogram of benzene (C6H6). What is the boiling point elevation of the resulting solution?

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Name: _____________________________________ Period: _____ Colligative Properties WS II

WS11.5

Directions: For each of the following questions use the appropriate relationship or equation to solve the problem.

1. What is the boiling point elevation and freezing point depression of a solution containing 50.0 g of glucose (C6H12O6) dissolved in 500.0 g of water?

2. What are the freezing point and boiling point of each of the following solutions? a. 2.75m NaOH in water

b. 0.586m of water in ethanol c. 1.26m of naphthalene (C10H8) in benzene

3. A rock salt (NaCl), ice, and water mixture is used to cool milk and cream to make homemade ice cream. How many grams of rock salt must be added to water to lower the freezing point 10.0C?

4. What is the freezing point and boiling point of a solution that contains 55.4 g NaCl and 42.3 g KBr dissolved in 750.3 mL H2O?

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How to ace the solutions unit. Solutions are ground zero in the chemical world- thats where most of the action is. Gases are difficult to contain, or even see. Solids dont react well because of surface area issues. Solutions, on the other hand, are easy to see, react, store, and work with. Its no surprise, then, that solutions are all around us. In the grocery store, at the gas station, in our bodies- solutions abound. This has been predominantly a hands-on unit. Once we familiarized ourselves with the vocabulary, we learned how to prepare solutions of different concentrations, and how to change their concentration. We also learned how solutes affect the melting point and boiling point of solutions. To help you ace this unit, we begin with a story to sharpen your language skills in this unit. Then we present some situations where solutions need to be prepared and their concentrations adjusted. And we finish with a road salt example of colligative properties in action. Dont forget to review your worksheets, PowerPoints, and labs before you take the solutions test. Read the story below and fill in the blanks and answer the questions as you go. The story is designed to include all of the new vocabulary and techniques you have learned. 1. Fill in the blanks to review the vocabulary used in this unit: Today I decided to make rock candy. I mixed sugar with water, so my solute is ________ and the solvent is _________, and since the resulting mixture was clear and colorless it was ______________. It took a while for the sugar to dissolve, probably because the big chunks of sugar made the molecular process of ___________ slow. I was surprised to see that this solution did not conduct electricity; apparently sugar is a _________________. I was also surprised to see how much sugar dissolved in water, sugar is highly _________________ in water. In fact I put so much sugar in that when I shook the solution it spontaneously crystallized; apparently the solution was __________________. Since I didnt add a seed crystal to the solution, this is specifically known as _______________ _______________. It was cool watching the first crystal form, that moment known as ___________________. I took one of my recrystallized sugar crystals and placed it under an atomic force microscope. I could see numerous O-H groups, which reminded me of water. I can see why the saying __________ ___________ __________ is used to predict solute-solvent solubilities. I would predict sugar to be ___________ in hexane (CH3CH2CH2CH2CH2CH3), and ____________ in ethanol (CH3CH2OH). To increase that solubility, I could _____________, _____________, or add more _____________, although one of these doesnt always work (__________________). I know that in the cases of gases, dissolved in liquids, solubility increases when the solution is _______________. And pressurizing a solution to dissolve more solute is an example of __________ __________ in action. 2. Henrys Law: Solubility is proportional to _____________. If the solubility of a solute in water is 2.8 g/L at 1 atmosphere pressure, and the pressure is increased to 3 atmospheres, the solubility will increase to ________ g/L. 22

3. Concentration and dilution For all of these questions you have 29 grams of table salt in 500 mL of solution. a. Describe how to prepare this solution

b. Calculate the percent salt by mass (water has a density of 1 g/mL)

c. Calculate the percent mass by volume (table salt has a density of 2.16 g/mL)

d. Calculate the molarity of the solution (table salt has a molar mass of about 58 g/mol)

e. This solution will have a (higher/lower) boiling point than pure water, and a (higher/lower) freezing point than pure water.

f. Calculate the molality of the solution (L1 only; assume 950 g water).

g. Calculate the freezing point of this solution (L1 only; Kf H2O = 1.86 OC/m; use data above for molality).

h. Calculate the boiling point elevation of this solution (L1 only; Kb H2O = 0.512 OC/m; use data above for molality).

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k. Solutions Packet Test 2