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Chemistry 30S/PGL Crystal Growing Project
Objective (What will I accomplish?)Work independently and apply the principles of solution chemistry to grow a crystal athome.
Rationale (Why am I doing this?)To develop a working understanding of the following terms.
• Solute
•• Solvent
•• Solution
•• Concentrated •
Soluble
• Mixture
• UnsaturatedInsoluble
• Heterogeneous • SaturatedHomogeneous • Precipitate
• SupersaturatedDilute
• Aqueous
• Crystal
Procedure1. Research and develop a procedure for growing a crystal at home.2. Conference with the teacher to articulate your method and have it approved.3. Display your crystal in a three dimensional exhibit.
Timeline
Project Stage Due Date(s)
1. Experimental MethodDue
2. Student & TeacherPlanning Conferences
3. Begin Growing Crystal
4. Crystal Exhibit
Bragging Rights Bonus CategoriesOne bonus mark will be awarded to each student that wins a bragging rights category, asdetermined by a class vote (silent auction method). No student may win more than onebragging rights title. No student may be awarded a bonus mark where the project markwould exceed 100%. The bonus mark in tied votes in any category will be split betweenno more than two winners, with each winner receiving one bonus mark. In the case of athree or more person tie in a single category winners will not be awarded a bonus mark.NOTE: in case of disagreement, the final decision to award a bonus mark rests with theteacher.
• Biggest crystal
• Best decorated
• Most functionallooking
• Most perfectlooking
• Smallest crystal
• Best display
• Coolest shape or design
• Most colourful• Greatest number of detached
crystals
Chemistr OS/PGL Crystal Growing Project
CRYSTAL GRO NG PROJECT ASSESSMENT RUBRIC
Name:P ANNING CONVERSATION
Criteria
Articulates amethod
Pictures of growingstages displayed
Crystal DisplayInformation
Crystal Display
Expert
(4 points)
Student articulates amethod personalized
to their homeenvironment to
successfully grow acrystal that requires
no revisions
CRYSTA
Minimum of threepictures illustrating
diverse stages ofgrowth includingsome method of
measurement clearlyvisible with date
stampsInformation aboutthe chemical used,the growing time,
the biggestchallenge, and themost rewarding
experienceassociated with
growing the crystalis communicated in
the display
Colourful,attractive, three-
dimensional displayincluding crystal
Intermediate(3-2 points)
Student articulates amethod to
successfully grow acrystal that requiresminor revisions (3)
or the studentrequires furtherinformation toarticulate their
method (2)EXHIBIT
One (3) or two (2)aspects of expert
level criteriamissing
Two (2) or three (3)criteria met
Two (2) or three (3)criteria met
Novice( -0 point)
Student is unable toarticulate a method
(0) or presents amethod that clearly
has not been thoughtout and/or is not
personalized to theirenvironment (1)
More than twoaspects of expert
level criteriamissing (1) or nopictures displayedof growing stages
(0)
Less than twocriteria met (1) or
no displayinformation present
(0)
Only one criteriamet (1) or no crystal
displayed (0)
/16
Chemistry 30S/PGL Crystal Growing Project
Voting Instructions
Silent Auction Method: Cut out each ticket. Cast your ballot by placing each ticket in theappropriate container.
^ggest Gr^stalMost Perfect
L Crystal
Coolest Cr^sttl
shape or Design
best Decorated
CrystalSmal lest Crystal
1"^ost Colourful
Crystal
Most Futr\!
CrystalFest Display
1 cst Detac{1ed
Crystals
Senteo Handheld Method: Record the number of the person you wish to vote for besidethe category name. Open voting document by clicking here.
CategoryCandidate
CategoryCandidate
Number Number1. Best Decorated 6. Most Detached
Crystal Crystals
2. Best Display b7. Most Functional
Crystal
3. Biggest Crystal --------- 8. Most PerfectLooking Crystal
4. Coolest Shape or 9. Smallest SingleDesign Crystal
5. Most ColourfulCrystal
_
_ nd
Reining a SolutionMisleading Labelling
Milk is sometimes labelled as "homoge-nized," meaning that the cream is equallydistributed throughout the milk. This use ofthe word does not match the chemistry defi-nition of homogeneous. Using the strictchemistry definition, milk is not a homoge-neous mixture, but a heterogeneous mixture.Milk is not a solution.
a homogeneous mixture of sub-stances composed of at least one solute andone solvent
_ a uniform mix-ture of only one phase
a substance that is dissolved in asolvent (e.g., salt, NaCl)
the medium in which a solute isdissolved; often the liquid component of asolution (e.g., water)
Figure 1Gasoline, shown here in a spill on asphalt, is
a nonaqueous solution containing many dif-
ferent solutes (mostly hydrocarbons such as
benzene and paraffin) in an octane solvent.
The composition of gasoline is not fixed: It
varies with the source of the raw material,
the manufacturer, and the season.
Many of the substances that we use every day come packaged with water. We buyother substances with little or no water, but then mix water with them before use.For example, we may purchase syrup, household ammonia, and pop with wateralready added, but we mix baking soda, salt, sugar, and powdered drinks withwater. Most of the chemical reactions that you see in high school occur in a waterenvironment. Indeed, most of the chemical reactions necessary for life on ourplanet occur in water.
Because so many substances dissolve in it, water is often referred to as theuniversal solvent. Of course, this is an exaggeration. Not all things dissolve inwater. Imagine if they did; we would not be able to find a container for water.
Before restricting our study to mixtures involving water, we will review themore general definition and types of a solution.
Solutions
Solutions are homogeneous mixtures of substances composed of at least onesolute and one solvent. Liquid-state and gas-state solutions are clear (trans-parent)-you can see through them; they are not cloudy or murky in appear-ance. Solutions may be coloured or colourless. Opaque or translucent (cloudy)mixtures, such as milk, contain undissolved particles large enough to block orscatter light waves. These mixtures are considered to be heterogeneous.
It is not immediately obvious whether a clear substance is pure or is a mix-ture, but it is certainly homogeneous. Homogeneous mixtures in the liquid stateand the gas state are always clear with only one phase present. If you were to doa chemical analysis of a sample of a homogeneous mixture (i.e., a solution), youwould find that the proportion of each chemical in the sample remains the same,regardless of how small the sample is. This is explained by the idea that there is auniform mixture of particles (atoms, ions, and/or molecules) in a solution.Empirically, a solution is homogeneous; theoretically, it is uniform at the atomicand molecular level.
Both solutes and solvents maybe gases, liquids, or solids, pro-
Table 1: Classification of Solutionsducing a number of different com-binations (Table 1). In metal alloys,such as bronze or the mercuryamalgam used in tooth fillings, thedissolving has taken place in liquidform before the solution is used insolid form. Common liquid solu-tions that have a solvent other thanwater include varnish, spray furni-ture polish, and gasoline. Gasoline,for example, is a mixture of as manyas 400 different hydrocarbons andother compounds (Figure 1). Thesesubstances form a solution-ahomogeneous mixture at the molecular level. There are many such hydrocarbonsolutions, including kerosene (a Canadian-invented fuel for lamps and stoves),and turpentine (used for cleaning paintbrushes). Most greases and oils will dis-solve in hydrocarbon solvents.
Solutein solvent Example of solution
gas in gas oxygen in nitrogen (in air)
gas in liquid oxygen in water (in most water)
gas in solid oxygen in solid water (in ice)
liquid in gas water in air (humidity)
liquid in liquid methanol in water (in antifreeze)
liquid in solid mercury in silver (in toothfillings)
solid in liquid sugar in water (in syrup)
solid in solid tin in copper (in bronze)
266 Chapter 6
6.1
Other examples of liquids and solids dissolving in solvents other than waterinclude the many chemicals that dissolve in alcohols. For example, solid iodinedissolved in ethanol (an alcohol) is used as an antiseptic (Figure 2). Aspirin(acetylsalicylic acid, ASA) dissolves better in methanol (a poisonous alcohol)than it does in water, for example, when doing chemical analyses. Of course, itshould never be mixed with alcohol when ingested. Some glues and sealantsmake use of other solvents: acetic acid is used as a solvent of the components ofsilicone sealants. You can smell the vinegar odour of acetic acid when sealingaround tubs and fish tanks.
The chemical formula representing a solution specifies the solute by using itschemical formula and shows the solvent by using a subscript. For example,
NH3(aq)
ammonia gas (solute) dissolved in water (solvent)
NaCl(aq)
solid sodium chloride (solute) dissolved in water (solvent)
l2(al)solid iodine (solute) dissolved in alcohol (solvent)
C2H5OH(aq)
liquid ethanol (solute) dissolved in water (solvent)
By far the most numerous and versatile solutions are those in which water isthe solvent (Figure 3). Water can dissolve many substances, forming manyunique solutions. All aqueous solutions have water as the solvent and are clear(transparent). They may be either coloured or colourless. Although water solu-tions are all different, they have some similarities and can be classified ordescribed in a number of ways. This chapter deals primarily with the character-istics of aqueous solutions.
Properties of Aqueous SolutionsCompounds can be classified as either electrolytes or nonelectrolytes.Electrolytes are solutes that form solutions that conduct electricity. At this pointwe will restrict ourselves to compounds in aqueous solutions. Compounds areelectrolytes if their aqueous solutions conduct electricity. Compounds are non -
electrolytes if their aqueous solu-tions do not conduct electricity.Most household aqueous solutions,such as fruit juices and cleaningsolutions, contain electrolytes. Theconductivity of a solution is easilytested with a simple conductivityapparatus (Figure 4) or an ohm-meter. This evidence also provides adiagnostic test to determine theclass of a solute-electrolyte ornonelectrolyte. This very broadclassification of compounds intoelectrolyte and nonelectrolyte cate-gories can be related to the maintypes of compounds classified inChapter 2. Electrolytes are mostly
_00 Thighly soluble ionic compounds
(e.g., KBrtaq)), including bases such as
Figure 4ionic hydroxides (e.g., sodium hydrox-
The bulb in this conductivity apparatus lightside, NaOH(aq}). Most molecular
up if the solute is an electrolyte.
The Nature and Properties of Solutions 267
Figure 2Tincture of iodine is a solution of the element
iodine and the compound potassium or sodium
iodide dissolved in ethanol. It is used to pre -vent the infection of minor cuts and scrapes.
a solute dissolved in
water
Figure 3
Concentrated hydrochloric acid (often sold
under its common name, muriatic acid) con-
tains hydrogen chloride gas dissolved in
water, It is used to etch concrete before
painting it, clean rusted metal, and adjust
acidity in swimming pools.
a compound that, in an
tion, conducts electricity
a compound that, in an
us solution, does not conduct electricity
I
ations in a suitable1. Carry out your Procedure, recording your obseformat.
6.1
(d) Using the evidence you have collected in your experiment, answer theQuestion: Which of the white solids labelled 1, 2, 3, and 4 is calcium chlo-ride, citric acid, glucose, and calcium hydroxide?
(e) Evaluate the evidence by critiquing the Experimental Design, Materials,and Procedure. Look for any flaws, sources of error, and possible improve-ments. Overall, how certain are you about your answer to the Question?
Understanding Concepts
1. Classify the following mixtures as heterogeneous or homogeneous.Justify your answers.(a) fresh-squeezed orange juice(b) white vinegar(c) red wine(d) an antique bronze dagger(e) a stainless steel knife(f) an old lead water pipe(g) humid air(h) a cloud(i) a dirty puddle
2. Which of the following are solutions and(a) milk(b) apple juice(c) the gas in a helium-filled balloon
poppure watersmoke-filled airsilt-filled waterrainwater14K gold in jewellery
3. State at least three ways of classifying solutions.
4. (a) What is an aqueous solution?(b) Give at least five examples of aqueous solutions that you can
find at home.
5. Using the information in Table 3, classify each of the compounds aseither an electrolyte or a nonelectrolyte. Provide your reasoning.
6. (a) What types of solutes are electrolytes?(b) Write a definition of an electrolyte.
7. Describe the solutes in the following types of solutions:(a) acidic(b) basic(c) neutral
8. Electrolytes are lost during physical activity and in hot weatherthrough sweating. The body sweats in order to keep cool-cooling by
which are not solutions?
(d)
(e)
(f)
(g)
(h)
(i)
Table 3
Compound Class
methanol molecularsodium chloride highly soluble ionic
hydrochloric acid acid (molecular)
potassium hydroxide base (ionic hydroxide)
The Nature and Properties of Solutions 269
GRADE 11 CHEMISTRY • Topic 4: Solutions
SKILLS AND ATrITUDES OUTCOMES
C11-0-Ul: Use appropriate strategies and skills to develop an understanding of chemical concepts.
ialogies, concept frames, concept maps, manipulatives, particulate representations, role-
uiations, sort-and-predict frames, word cycles...
C11-0-R1: Synthesize information obtained from a variety of sources.
include: print and electronic sources, specialists, other resource people
with a small crystal seed placed at the bottom. The crystal solid that results willform a tall column in the beaker if poured slowly. The column is fragile.
TEACHER NOTES
Most chemical reactions occur in an aqueous medium, and not in the solid, liquid,or gaseous phase. Students should be familiar with the nine types of solutionspresented. below and should be able to provide an. example for each. Emphasize thatthe smaller amount in a solution is usually classified as the solute and the largeramount the solvent. Ask students to provide examples other than those presentedbelow.
Types of Solutions
Solution Example
solid in solid •
copper in silver (sterling silver).
zinc in copper (brass)
solid in liquid •
salt in water (ocean water)•
iodine in alcohol (tincture)
solid in gas •
microscopic particulates in air•
mothball particles in air
liquid in solid •
mercury in silver amalgams (tooth fillings)*
liquid in liquid •
ethylene glycol in water (engine antifreeze)•
methanol in water (gas line antifreeze)
liquid in gas •
water vapour in air
gas in solid •
hydrogen in palladium** (purification of hydrogen)•
poisonous gases adsorbed in carbon (charcoal filter)
gas in liquid •
carbon dioxide in beverages (carbonated beverages)•
oxygen in water (supporting aquatic life)
gas in gas •
oxygen in nitrogen (air)
Have students ask their dentists to explain the use of a known carcinogen in an amalgam fororal/dental use.
** At room temperature, palladium will absorb 900 times its own volume of hydrogen.
Journal Writing
Have students relate the demonstration/discrepant event in their journals. Studentscould also include their dentists' explanation of the use of a known carcinogen in anamalgam for oral/dental use (as a follow-up).
Topic 4: Solutions
Dissolving of Molecular and Ionic Compounds
H
C12H220:11
Sucrose dissolved in water
The dissociation of
sodium chloride
into positive and
negative ions
Na*
CI
Na'
CI k Na' Cl
H
Na
Ci .., ;. Na`
H
CI
Na' K", ClH
IV Cr1 (s)
N (aq)+ Cl
(aq)
0 Copyright 2002 Nelson Thomson Learning
29
Inter m o ec ices ai
Polar solute molecules (in red) are surrounded by polarsolvent molecules (in green).
-H
H-0:------- H-N-H------- :O-H
H
H
H
:O-H
H
Multiple hydrogen bonds between ammonia and water result ina very high solubility for ammonia.
0 Copyright 2002 Nelson Thomson Learning
28
SOLUTIONS: TYPES OF SOLUTIONS
Objective: Differentiate among unsaturated, saturated, and supersaturated solutions.
Equipment and Chemicals: Lab Setup:
5OmL1.
Burnerbeaker
3.
Test tube holder
4.
Dropper pipet5.
Small test tubes6.
Flint striker(3)7.
sodium thiosulfate pentahydratecrystals
Safety:1. Wear safety goggles over your eyes2. Observe all glassware precautions3. Observe all fire precautions4. Clean up all spills immediately5. Rinse affected areas with lots of running water6. Sodium thiosulfate pentahydrate may be harmful if swallowed and may cause
irritation to skin, eyes, and mucous membranes.7. Wash your hands with soap and water after conducting the experiment.
Procedure:1. Obtain all materials.2. Label three test tubes A, B, and C.3. Half fill test tube A with sodium thiosulfate pentahydrate crystals. Return to your
lab station.4. Remove 5 crystals and set aside. Pour half of the remaining sodium thiosulfate
pentahydrate into test tube B.5. Place two of the 5 reserved crystals into test tube C.6. Add one half complete dropper pipet of water to each test tube. Drum test tubes
B and C with your fingers to dissolve each solution.7. Clamp test tube A with test tube holders and gently heat in a burner flame for 3 to
5 seconds at a time. Use the proper technique for heating and mixing as describedto you by the instructor.
8. Fill a 250 mL beaker with about 175 mL of cold tap water. Gently place each testtube into the cold water to cool. Wait three minutes. Do not agitate any of thesolutions.
9. One at a time, remove each test tube from the water bath, dry the outside withpaper towel, and insert a single crystal into the solution. Hold the bottom of eachtest tube in your hand. Record your observations.
10. Drum test tubes B and C on your fingers in an attempt to dissolve the crystal.11. Dissolve any solids remaining in the test tubes and rinse down the sink with lots
of water.12. Rinse all remaining glassware with lots of tap water and put all equipment away.
SOLUTIONS: TYPES OF SOLUTIONS
Observations:Test Tube A Test Tube B Test Tube C
Questions:1. Identify which solutions are unsaturated, saturated, and supersaturated.
2. Describe the differences between unsaturated, saturated, and supersaturated solutions.
TYPES OF SOLUTIONS LAB RUBRICCriteria Novice Intermediate Expert
Student observes Student does not Student is naggedAll aspects of the
proper safety wear their safety once or more aboutlab are conducted in
precautions goggles or has a lab not following propera safe manneraccident safety precautions
Student follows Evidence that theEvidence that the
written and student has notstudent has not Student follows all
verbal followed more thanfollowed one written written or verbal
instructions one written or verbalor verbal instruction instructions
instruction
Evidence of Little or no evidence Some evidence that a Evidence that all
equitable of equitable group member group members
participation participation by a participated more participatedgroup member than another equitably
More than one pieceEvidence of Entire station is
Lab station is of evidence remainschemicals or a piece cleaned up with no
cleaned up after of chemicals orof equipment remains evidence remaining
lab equipment afterafter cleanup of equipment or
cleanup chemicals
Solubility Curve of KN03
ObjectiveConstruct a solubility curve of potassium nitrate.
Chemicals• KNO3
• Tap water
SafetyDo not burn yourself on the hotplate. Be careful with glassware and thermometres.
Equipment•
Test tube
•
Temperature probe
•
Hotplate•
Test tube
10 mL graduated
•
250mL beakersholder
cylinder
(2)•
Dropper pipet
Procedure
1. Set up a water bath by filling a 250 mL beaker with approximately 175 mL of tapwater and carefully placing it on a hotplate. Set the hot plate to high. One groupmember should be consciously monitoring the water bath at all times.
2. Obtain all materials. Boot the computer, launch the software package, and set upthe temperature probe. Press the MON button to activate the sensor.
3. Place clean dry test tube in a clean 250 mL beaker.4. Label the test tube with an indelible marker if you are sharing a water bath.5. Obtain the appropriate mass of potassium nitrate in your test tube, as instructed by
your teacher.6. Fill a clean 10 mL graduated cylinder with 10.0 mL of tap water. Using a dropper
pipet, suction out 2.0 mL of water and add it to the test tube. Be sure to read themeniscus properly as directed by your instructor.
7. Insert the clean dry temperature probe into the test tube.8. Place the test tube with the probe in it into the hot water bath to dissolve the
KNO3. Monitor your solution and the cord to prevent any lab accidents.9. Once your solution has completely dissolved, using a test tube holder remove the
test tube from the water bath with the temperature probe still in it and place in theempty 250 mL beaker. Turn off the hotplate and unplug it. Carefully transportthe beaker and test tube to your lab station.
10. Continuously observe your solution with stirring as it cools, recording thetemperature at which crystals first begin to appear. Record the temperature in thetable below beside your corresponding mass of KNO3.
11. Repeat steps 7 to 9 as many times as possible in order to obtain precise results.12. To clean up, return your test tube and thermometer to the hot water bath. Allow
solutions to dissolve and empty them into the appropriate beaker for recycling.13. Rinse all equipment with lots of water and put it away.
www. pembinatrails.ca/shaftesbury /mrdeakin
adeakin pembinatraiis.ca204) 888-5898 'L Shaftesbury High School, 2240 Grant Ave, Wpg, MB, R3P OP7
Solubility Curve of O
Quantitative DataMass and Temperature Data for Saturated Potassium Nitrate Solutions
Mass of KNO3 (g) Volume of water (mL) Crystallization Temperature (°C)
Trial 1 Trial 2 Trial 3 Average
1.00
1.50
2.00
2.50
3.00
3.50
4.00
CalculationsShow a sample calculation of the conversion of grams KNO3 per volume of water tograms KNO3 per 100 mL water.
SOLUB TY CURVE OF O, LAB RUBRIC
Criteria Novice Intermediate Expert
Student observes Student does not Student is naggedAll aspects of the
proper safety wear their safety once or more aboutlab are conducted in
precautions goggles or has a lab not following propera safe manneraccident safety precautions
Student follows Evidence that theEvidence that the
written and student has notstudent has not Student follows all
verbal followed more thanfollowed one written written or verbal
instructions one written or verbalor verbal instruction instructions
instruction
(
Evidence of Little or no evidence Some evidence that a Evidence that all
equitable of equitable group member group members
participation participation by a(
participated more participatedgroup member than another equitably
More than one pieceEvidence of Entire station is
Lab station is of evidence remains
I chemicals or a piece cleaned up with nocleaned up after of chemicals or o f
equipment remains evidence remaininglab equipment after
after cleanup of equipment orcleanup chemicals
www.pembinatrails.ca/shaftesbury/mrdeakin ' adeakinCapembinatrails.ca(204) 888-5898 J Shaftesbury High School, 2240 Grant Ave, Wpg, MB, R3P OP7
Solubility Curve of KNO
Conclusion1) Construct and hand in a graph of mass of KNO3 per 100 mL H2O on the y - axis
versus temperature on the x - axis.2) Draw the curve of best fit.
Questions:
1) Describe the relationship between the solubility of KNO3 and the temperature ofthe solvent.
2) Using your graph, determine how many grams of KNO3 can be dissolved in 100grams of water at the following temperatures:
a) 35°C
b) 60°Cc) 70°C
3) Predict whether the following solutions of KNO3 would be considered saturated,unsaturated or supersaturated.
a) 75 g of KNO3 in 100 ml waterb) 60 g of KNO3 in 100 ml of water.
www.pembinatrails.ca/shaftesbury/mrdeakin "5 [email protected] (204) 888-5898 J Shaftesbury High School, 2240 Grant Ave, Wpg, MB, R3P OP7
GRADE 11 CHEMISTRY - Topic 4 Appendices
pendix 4.6: Solubility Curve
0 40 50 60 70 80 90 100
Temperature (°C)
0 10 20
150
140
0
120
400
0
20
10
0
Topic 4 Appendices - 17
ZjVLUDM11-T %wUKVC*Answer the following questions basedon the scslublllty curve below.
h salt is least soluble In water
at 20' C?
2. How many grams of potassium
chloride can be dissolved in 200 g
of water at 80° C?
3. At 40' C, how much potassium
nitrate cs b be dissolved Jn.300. g of __ r4water?
__ s-
4. Which salt shows the least change
In solubility from 0° - 100° C?
At 30° C, 90 g of sodium nitrate Is
dissolved in 100 g of water. Is this
solution saturated, unsaturated or
supersaturated?
wvme
IleI I I 001YI,=--]
Lj90
"k ZI
I;rA -A-70
A-K
Hf-
-
_-, H
20 30 40 50 80 70 80 90 100
Temperature (0°C)
CO 1
1
140
130
4120
0
-60
40
30
20
10
0
6. A sat uroted-soiutlon-ofpatassium chlorate is formed from one hundred grams ofwater. If the saturated solution Is cooled from 80° C to 50° C, how many grams ofprecipitate are formed?
7. What compound shows a decrease Insolubility from 011 to 100° C?
Which salt Is most soluble at 10° C?
9. Which salt is least soluble at 50° C?
Which salt is least soluble at 900 C?
:hemistry lF8766
67
®lnstructtonal Fair, I
Date
Class
Text Reference: Section 16-2
Name
CHAPTER 16 REVIEW ACTIVITY
Solubility Curves
Study the solubility curves in the figure, and thenanswer the questions that follow.
1. What relationship exists between solubilityand temperature for most of the substancesshown?
2. a. What is the exception?
b. What general principle accounts for this ex-ception?
3. a. Approximately how many grams of NaNO3will dissolve in 100 g of water at 20°C?
b. How many grams will dissolve at 60°C?
4. How many grams of NH4CI will dissolve in1 dm3 of H2O at 50°C?
5. Ninety grams of NaNO3 is added to 100 g of H2Oat 0°C. With constant stirring, to what temperaturemust the solution be raised to produce a saturatedsolution with no solid NaNO3 remaining?
6. A saturated solution of KCIO3 was made with300 g of H2O at 40°C. How much KC1O3 could berecovered by evaporating the solution to dryness?
7. live hundred grams of water is used to make asaturated solution of KCI at 10°C. How many moregrams of KCI could be dissolved if the tem-perature were raised to 100°C?
8. A saturated solution of KNO3 in 200 g of H2O at50°C is cooled to 20°C. How much KNO3 will pre-cipitate out of solution?
3. a.
b.
4.
5.
6.
7.
8.
COPYRIGHT by Prentice Hall, Inc.Reproduction of this master is restricted to duplication for classroom use only.
2. a.
b.
100
CHEMISTRY: The Study of Matter
16-11
III!
I H111111111
11-^[if
IIIIIIIII
fillfit III IIIIIH-11 If
IIt III IIIHIL-11 IIII
11111
1111111
if
IIIPbGUSkAm- nltr.tt
If 11,111-J-47
111 11
Soc9utn ^He
fill
-1-111 H HEIA
III [till It it tillIIII, ; 11illf If 1114T]10 20 30 40 50 . 00
70 e0 90 100
Temper.tur! ("C)
potassium sulfate
240
22
t20
a
k
25
j
010 20
7060 90
Temperature (°C}
SCIENCE
' Solubility Calculations .................................................. ....................«.N..«.....
1. Calculate the maximum number of grams of each solute that can be dissolved:
a) potassium nitrate in 300 cm3 b) sodium chloride in 1 250 cm3
c) sodium nitrate in 50 cm3
of water at 80° C,
I
of water at 40° C.
I of water at 00 C.
2. Calculate the minimum volume of water needed to dissolve;
a) 5170 g of sodium chloride
b) 10.0 g of potassium nitrate
c) 1.00 kg of sodium nitrate
in water at 1 000 C.
I
in water at 010 C.
I
in water at 500 C.
3. Calculate the temperature the water must be to just dissolve;
a) 80.0 g of potassium nitrate
b) 60.0 g of potassium nitrate
in 200 cm3 of water.
in 50 cm3 of water.
4. Calculate the mass of precipitate in each case below;
The temperature is then changed to 13° C.
a) a saturated solution of sodium nitrate
in 400 cm3 of water at 100' C is made.
c) 500.0 g of sodium niaze
in 500 cm3 of water.
b) a saturated solution of potassium nitrate
in 250 cm3 of water at 8O° C is machThe temperature is then changed to 8° C.
Molarity Practice Problems
1) How many grams of potassium carbonate are needed to make 200 mL ofa 2.5 M solution?
2) How many liters of 4 M solution can be made using 100 grams of lithiumbromide?
3) What is the concentration of an aqueous solution with a volume of 450that contains 200 grams of iron (II) chloride?
4) How many grams of ammonium sulfate are needed to make a 0.25 Msolution at a concentration of 6 M?
5) What is the concentration of a solution with a volume of 2.5 literscontaining 660 grams of calcium phosphate?
6) How many grams of copper (II) fluoride are needed to make 6.7 liters of a1.2 M solution?
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O 2000 Cavalcade Publishing, All Rights Reserved
Making Solutions Practice Problems
Explain how you would make the following solutions. Your answer should be astatement, not just how many grams of the substance you need to make thesolution.
7)2Lof6MHCI
8)
0.75 L of 0.25 M Na2SO4
9)
250 mL of 0.75 M lithium nitrite
10) 4.5 mL of 0.05 M magnesium sulfate
11) 90 mL of 1.2 M BF3
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Making a Solution Lab
Before you begin to obtain glassware and chemicals,know that EACH member of the group must check inwith Mr. Deakin 3 times during this experimen
1. Show me your complete answer, including yourstatement - to the prompt:
Explain how to make a 100.00 mL solution of 0.20mol/L potassium nitrate.
2. Show me your dissolved solution BEFORE youpour it into the volumetric flask.
3. Show me how you lined the meniscus up with thegraduation mark on the neck of the volumetricflask BEFORE you invert and mix your solution.
DILUTING A SOLUTION LAB
Purpose:Prepare a 0.016 mol/L solution from 100.00 mL of 0.20 mol/L stocksolution of potassium nitrate.
Chemicals & Equipment:• 100.00 mL of 0.20 mol/L potassium nitrate
• Droppersolution
pipet• 150 mL beaker
• 50 mL beaker• Distilled water
• Funnel• 10 mL graduated cylinder
Procedure:1. Obtain all chemicals and equipment.2. Empty all of 0.20 mol /L stock solution into a 150 mL beaker.3. Rinse the volumetric flask 3 times with very small amounts of
distilled water. Fill 1/3 full with distilled water and set aside.4. Fill a 10.0 mL graduated cylinder with the correct amount of stock
solution. Use a dropper pipet to obtain a precise amount.5. Check your work with the instructor before moving on to the next
step.6. Pour the solution from the graduated cylinder into the volumetric
flask.7. Fill to just under the calibration mark.8. Put a very small amount of distilled water into a 50 mL beaker and
use the dropper pipet to fill the volumetric flask to the calibrationmark.
9. Stopper your solution and check with your instructor.10.Invert the solution 3 times to mix.11. Rinse all remaining solutions down the drain with lots of running
water, rinse remaining and put everything away.
DILUTING A SOLUTION LAB
Before you begin to obtain glassware and chemicals, EACHmember of the group must check in with Mr. Deakin 3 timesduring this experiment.
1. Show me your complete answer, including your statement- to the prompt:
Explain how to make a 100.00 mL solution of 0.016 mob Epotassium nitrate from a 0.20 moliL stock solution.
2. Show me a volumetric flask 1/3 full of water and agraduated cylinder filled with 10.0 mL of 0.20 mol/Lstock solution.
3. Show me how you lined the meniscus up with thegraduation mark on the neck of the volumetric flaskBEFORE you invert and mix your solution.
DILUTING A SOLUTION LAB RUBRICCriteria Novice Intermediate Expert
Student observes Student does not wearStudent is nagged once All aspects of the lab
proper safety their safety goggles oror more about not
are conducted in a safeprecautions has a lab accident
following proper safetymanner
precautions
Student followsEvidence that the Evidence that the
written andstudent has not student has not
Student follows all
verbalfollowed more than one followed one written or
written or verbal
instructionswritten or verbal verbal instruction
instructionsinstruction
Evidence of Little or no evidence ofSome evidence that a
Evidence that allequitable equitable participation
group membergroup members
participation by a group memberparticipated more than
participated equitablyanother
More than one piece ofEntire station is
Lab station isevidence remains
Evidence of chemicals cleaned up with nocleaned up after
echemicals or equipment
or a piece of equipment evidence remaining oflab after cleanup
remains after cleanup equipment orchemicals
Dilutions Worksheet
12)lf I have 340 mL of a 0.5 M NaBr solution, what will the concentration be if Iadd 560 mL more water to it?
13)lf I dilute 250 mL of 0.10 M lithium acetate solution to a volume of 750 mL,what will the concentration of this solution be?
14)lf I leave 750 mL of 0.50 M sodium chloride solution uncovered on awindowsill and 150 mL of the solvent evaporates, what will the newconcentration of the sodium chloride solution be?
15)To what volume would I need to add water to the evaporated solution inproblem 3 to get a solution with a concentration of 0.25 M?
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Writing Balanced Ionic Equations for Precipitate Reactions
Write the balanced dissolving ionic (DIE), overall ionic (OIE), and the net ionicequations (NIE) when:
1. a solution of silver nitrate is mixed with sodium iodide solution.
2. solutions of potassium chromate and strontium bromide combine.
3. an ammonium hydroxide solution is mixed with a solution of copper (I) chromate.
4. aqueous lithium sulphate combines with dissolved calcium iodide.
4) 0
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2 (204) 888-5898
Shaftesbury High School, 2240 Grant Ave, Wpg, MB, R3P OP7
Solubility Rules Worksheet
1. Name or give the chemical formula for each of the followingcompounds.
2. State whether they are soluble (will dissolve) or insoluble (will notdissolve) in solution. Use solubility rules.
Chemical Formula Name Solubili1. NH4CH3COO2. Ba(OH)23. Iron (II) Carbonate4. NaOH5. RbNO36. Cesium Sulfate7. MgSO48. ZnC129. Zinc Hydroxide1 O.Zn3(PO4)2
11.AgBr12.KNO313.Al2S314. Silver Acetate15.Sr2CrO416. Aluminum Phosphate
17.BaSO418. Ca(OH)219.BaCO320.MgCrO421. Iron (III) sulfide22.NH4CN23. Silver Iodide24.Hg2SO425. Lithium Chloride
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Solubility Chart
Negative Ions Positive Ions Solubility
Essentially All Alkali ions (Li+, Na', K+, Rb+, Cs+) Soluble, (aq)
Essentially All Hydrogen ion, H+ Soluble, (aq)
Essentially All Ammonium ion, NH4' Soluble, (aq)
Nitrate, NO3" Essentially Alt Soluble, (aq)
Acetate,CH3COO
Essentially All, EXCEPT Ag+ Soluble, (aq)
Chloride, Cl--
z+
z+Ag , Pb
, Hgz
, Cu , TlLow Solubility,
Bromide, Br(s)
Iodide, I- Alt others Soluble, (aq)
zSulfate, SO4Ag+, Caz+, Srz+, Baz+, Pbz+
Raz+ Low Solubility,(s)
All others Soluble, (aq)Alkali ions and H% NI-14% Be +, Mg +, Ca l%
z+ z+z+Soluble (aq)Sz_
S lfidSr , Ba , Ra
,u e,
All othersLow Solubility,
(s)Alkali ions and H+, NH4, Sr +, Ba +, Ra +, TL+ Soluble, (aq)
Hydroxide, OH-Alt others
Low Solubility,(s)
Phosphate, Alkali ions and H+, NH4+ Soluble, (aq)P043-Carbonate,
2-C0
All othersLow Solubility,
3(s)
Sulfite, S03 2-
Chromate, Baz+, Srz+
Pbz+, Ag+ Low Solubility,2C 04r
All others Soluble, (aq)
f) P1
Solubility Rules Lab
Objectives1. Examine the solubilities of pairs of ionic solutions in double displacement
reactions.2. Write balanced dissociation, overall ionic, and net ionic equations for precipitate
reactions.3. Verify the solubility rules.
Lab Setup
1. Paper towel
2. Aqueous solution of ions3. Watch glass 4. Tap water5. Glass stir rod
Chemicals1. 0.1 M AgNO3(aq)
2. 0.5 M Pb(N03)2(aq) 3. 0.5 M K2Cr04(aq)4. 0.1 M Fe(NO3)3(aq) 5. 6.0 M NaOH(aq)
6. 0.5 M Nahaq)
Safety• Wear safety goggles over your eyes at all times during the experiment• Clean up all spills immediately with copious quantities of tap water• Rinse affected areas with copious quantities of running tap water• All solutions are poisonous, AgNO3 permanently stains skin and clothing dark brown,
and NaOH is corrosive, so observe appropriate precautions
Procedure1. Into a clean, dry watchglass, add two drops of your solution.2. Combine your solution with two drops of another solution. Mix with a clean, dry
stir rod. Record your observations.3. repeat steps 1 and 2 until you have combined your solution with every other
solution.4. Rinse all glassware with copious quantities of tap water, dry all equipment, and
return it to its original location.
9
Solubility Rules Lab
Data & Observations
Solution &Observation
BalancedDissociation
Equation
Cations do NOTdissolve withthese Anions
Anions do NOTdissolve withthese Cations
2.
3.
4.
5.
6.
Balanced DIE, OIE, NIE
ConclusionExplain how the results of the experiment verify the solubility rules.
Answers
2. 7.5% VN
3. 32% WN
4. 4.8% W/W
5.8 mg
6. 5.4 ppm
7. (a) 1/1000
(c) 30ug
8. 1.8 mol/L
Understanding Concepts
1. What are three different ways of expressing the concentration of asolution?
2. Gasohol, which is a solution of ethanol and gasoline, is considered tobe a cleaner fuel than just gasoline alone. A typical gasohol mixtureavailable across Canada contains 4.1 L of ethanol in a 55-L tank offuel. Calculate the percentage by volume concentration of ethanol.
3. Solder flux, available at hardware and craft stores, contains 16 g ofzinc chloride in 50 mL of solution. The solvent is aqueous hydrochloricacid. What is the percentage weight by volume of zinc chloride in thesolution?
4. Brass is a copper-zinc alloy. If the concentration of zinc is relativelylow, the brass has a golden colour and is often used for inexpensivejewellery. If a 35.0 g pendant contains 1.7 g of zinc, what is the per-centage weight by weight of zinc in this brass?
5. If the concentration of oxygen in water is 8 ppm, what mass ofoxygen is present in 1 L of water?
6. Formaldehyde, CH2Oigi, is an indoor air pollutant that comes fromsynthetic materials and cigarette smoke. Formaldehyde is controver-sial because it is a probable carcinogen. If a 500-L indoor air samplewith a mass of 0.59 kg contained 3.2 mg of formaldehyde, this wouldbe considered a dangerous level. What would be the concentration offormaldehyde in parts per million?
7. Very low concentrations of toxic substances sometimes require theuse of the parts per billion (ppb) concentration.(a) How much smaller is 1 ppb than 1 ppm?(b) Use the list of equivalent units for parts per million to make a
new list for parts per billion.(c) Copper is an essential trace element for animal life. An average
adult requires the equivalent of a litre of water containing 30 ppbof copper a day. What mass of copper is this per kilogram ofsolution?
8. A plastic dropper bottle for a chemical analysis contains 0.11 mol ofcalcium chloride in 60 mL of solution. Calculate the molar concentra-tion of calcium chloride.
Making Connections
9. Toxicity of substances for animals is usually expressed by a quantitydesignated as "LD50." Use the Internet to research the use of thisquantity. What does LD50 mean? What is the concentration in ppm fora substance considered "extremely toxic" and one considered"slightly toxic"?Follow the links for Nelson Chemistry 11, 6.3.
Reflecting
10. How is your report card mark in a subject like a concentration? Whatother ratios have you used that are similar to concentration ratios?
Calculations Involving ConcentrationsSolutions are so commonly used in chemistry that calculating concentrationsmight be the primary reason why chemists pull out their calculators. In associ-ated calculations, chemists and chemical technicians also frequently need to cal-
284 Chapter 6
6.3
14.8 mol
1L
VNH3=2.5L
nNH3 = 2.5
x 14.8 mod
1Y
nNH_ = 37 mol
The amount of ammonia present in the bottle is 37 mol.
You should always check that your answer makes sense. For example, inSample Problem 8, 14.8 mol/L means that there is 14.8 mol of ammonia in 1 Lof solution. Therefore, 2.5 L, which is greater than i L, must produce an amountgreater than 14.8 mol.
In some situations you may know the molar concentration and need to findeither the volume of solution or amount (in moles) of solute. In these situationsuse either the volume/amount or amount/volume ratio. Notice that the units ofthe quantity you want to find should be the units in the numerator of the con-version factor ratio.
What volume of a 0.25 mol/L salt solution in a laboratory contains 0.10 mol ofsodium chloride?
0.25 mol"NaCI =
1L
nNaCI = 0.10 mol
v
=0.10
x
1LNaC1
0.25 ^rrdl
VNaCI = 0.40 L
You need 0.40 L of salt solution to provide 0.10 mol of sodium chloride.
Understanding Concepts
11. Rubbing alcohol, C3H7OH11), is sold as a 70.0% VN solution forexternal use only. What volume of pure C3H701-10) is present in a 500-mL (assume three significant digits) bottle?
12. Suppose your company makes hydrogen peroxide solution with ageneric label for drugstores in your area. What mass of purehydrogen peroxide is needed to make 1000 bottles each containing250 mL of 3.0% WN H2O2(aq)?
13. The maximum acceptable concentration of fluoride ions in municipalwater supplies is 1.5 ppm. What is the maximum mass of fluorideions you would get from a 0.250-L glass of water?
Figure 5Aqueous ammonia is purchased for sciencelaboratories as a concentrated solution. Whatis the concentration of the solute?
Answers
11. 0.350 L
12. 7.5 kg
13. 0.38 mg
The Nature and Properties of Solutions 287
CONCENTRATION QUESTIONS
Toothpaste contains 0.24 % w/w of sodium fluoride. If 0.50 g of toothpaste issqueezed onto a toothbrush, what mass of sodium fluoride is used? (0.0012 g)
2. Zinc oxide is the main ingredient in sunscreen. A premium brand advertises itssunscreen contains 10 % w/v of zinc oxide. What size bottle contains 23 grams ofzinc oxide? (230 mL)
3. The maximum contaminant level of lead in drinking water is 15 ppb. Assuming awater source has 15 ppb of lead, what mass of lead are you drinking if youconsume 2 L of water a day? If lead accumulates in the fat cells of your body,how many grams of lead are in your body after 1 year? (3 x 10-5 g, 0.01095 g)
4. Tincture of iodine is used as a disinfectant for boo-boos. If 25 mg/mL ofpotassium iodide is dissolved in a bottle of iodine tincture, what percent by massis the solution? (2.5 % w/v)
5. Joanne drinks water containing 0.08 g of dissolved minerals. What concentrationin parts per million of minerals is present in a 500 mL bottle of water? (160 ppm)
DILUTION QUESTIONS
6. Natalie likes to feed the humming birds in her garden. If she dissolves 12 g offructose - chemical formula C6H1206 - in 250 mL of water, what is theconcentration of her sucrose solution? (0.27 mol/L)
7. If humming birds are partial to a 0.10 M solution of fructose and Natalie's birdfeeder only holds 100 mL of solution, how much of her original solution must shedilute to make a new 0.10 M solution? (37 mL)
Limiting Factor Questions
For each of the following pairs of solutions,a) write the balanced dissolving equations
b) write the balanced overall ionic equationc) write the balanced net ionic equation
d) calculate the concentrations of all ions in solutione) calculate the mass of the precipitate
125 mL of 0.25 M barium iodide solution and 75 mL of 0.10 M sodium sulfatesolution are mixed.
2. Two solutions containing 200 mL of 0.15 M strontium chloride and 150 mL of 0.09 Mpotassium chromate are mixed.
225 mL of 0.5 M silver nitrate solution and 275 mL of 0.12 M lithium iodide solutionare mixed.
4. Two solutions containing 150 mL of 0.15 M lithium chloride and 150 mL of 0.10 Mlead (II) acetate are mixed.
A 50 mL solution of magnesium nitrate with a concentration of 0.20 M is combinedwith 100 mL of 0.15 M rubidium hydroxide.
6. 100 mL of 0.10 M ammonium phosphate solution is mixed with 200 mL of 0.12 Msilver nitrate solution.
7. A 150 mL solution of potassium hydroxide with a concentration of 0.40 M is
combined with 100 mL of 0.15 M aluminum acetate.
8. Two solutions containing 100 mL of 0.10 M sodium carbonate and 200 mL of 0.10 M
aluminum chloride are mixed.
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