Do Now

Do NowDefine the following words:SoluteSolventSolution

Provide an example of each

1C. Investigating the 1C. Investigating the Cause of the Fish KillCause of the Fish KillObtaining the knowledge & skills needed to evaluate Snake River water data & to determine the cause of the fish kill

1C. Objectives1C. ObjectivesExplain the solubility of

substances in waterDescribe the behavior of ionic

compounds, heavy metals, acids & bases, molecular substances, & gases (particularly oxygen) in water

1C.1 SOLUBILITY OF 1C.1 SOLUBILITY OF SOLIDS IN WATERSOLIDS IN WATER

What is solubility?What is solubility?Imagine

dissolving a spoonful of salt in water

What is solubility?What is solubility?The salt is the ____________The water is the ______________The mixture of the salt & the

water is a __________________As you stir, the white crystals

dissolve in the waterThe solution is colorless & clear

What is solubility?What is solubility?What would happen if you added

another spoonful of salt?And another…. And another?Eventually, you wouldn’t be able to

dissolve any more. Some salt would fall to the bottom, no matter how long you stirred.

The solution would be saturated; it would hold all the solute it could.

No more salt can dissolve.The solution is saturated.

What is solubility?What is solubility?If you heated the water, you might

be able to dissolve a little more salt.

The maximum quantity of a substance that can dissolve in a certain quantity of water – at a specified temperature – is called its solubility.

You might say grams of salt per 100 grams of water at 20oC

What is solubility?What is solubility?Although size of the salt crystals

& how vigorously you stir affect how long it would take for the salt to dissolve, they do not affect how much can dissolve at a specified temperature

Temperature & SolubilityTemperature & SolubilityThe amount of

solute that can dissolve in a specified amount of solvent varies with temperature

The graphical representation of this relationship is called the solute’s solubility curve

Temperature & SolubilityTemperature & SolubilityEach point on the

solubility curve indicates a solution in which the solvent contains as much dissolved solute as it normally can at that temperature

Such a solution is called a saturated solution

Temperature & SolubilityTemperature & SolubilityQuestion: At

40oC, how much KNO3 will dissolve in 100 g water to form a saturated solution?

Answer:


90oC, how much KCl will dissolve in 100 g water to form a saturated solution?

Answer:


what temperature will 70 g of KNO3 dissolve in 100 g of water to make a saturated solution?

Answer:

Temperature & SolubilityTemperature & SolubilityQuestion: Which

one of the three solutes is the most affected by temperature?

Answer: Question: The

most affected?Answer:

Temperature & SolubilityTemperature & SolubilityThink about a

solution that contains 80 g of KNO3 in 100 g of water at 60 oC

The point is below the curve

This is an unsaturated solution

Temperature & SolubilityTemperature & SolubilityWhat do you expect would happen

if you cooled a saturated solution?Crystals would form and fall to the

bottom – usuallySometimes, cooling a saturated

solution does not cause crystals to fall out

This is an unstable solution called a supersaturated solution

QuestionHow much potassium nitrate will

dissolve in 150g of water at 40°C?

Answer:

ROCK CANDYROCK CANDY

When seed crystals are added to a supersaturated sugar solution, they cause excess dissolved sugar to crystallize onto a string

HOT SPRINGSHOT SPRINGSAs the water in Emerald Pool (Yellowstone National Park) cools and evaporates at the edges, it becomes supersaturated, and precipitates begin to form.

Do NowTurn to page 76 and use the

chart: What mass of O2 can be

dissolved in 2000.0 g of water at 30.0 °C?

Take out the worksheet and the homework (pg. 85 #1-5) from the other night.

Objectives1. SWBAT define Saturated,

supersaturated, and unsaturated solutions.

2. SWBAT answer questions about solubility curves and practice reading and interpreting graphs.

Stand Up and turn to the person next to you…Let’s Review the following words: SoluteSolventSolutionSaturated UnsaturatedSupersaturated

Pg. 56 #1-3

1C.1 SUPPLEMENT: 1C.1 SUPPLEMENT: SOLUBILITY & SOLUBILITY & SOLUBILITY CURVESSOLUBILITY CURVES

1C.2 Solubility & Solubility Curves, pp. 55-56As extra practice, you could read the sample problems & try the 3 questions at the bottom of p. 56.

1C.3 CONSTRUCTING 1C.3 CONSTRUCTING A SOLUBILITY CURVEA SOLUBILITY CURVE

Investigating Matter, pp. 57-59

Do NowExplain why the crystals formed

in the experiment yesterday.

Objectives1. SWBAT create a solubility

curve based on their results 2. SWBAT describe two separate

steps required in the dissolving process;

3. SWBAT explain how water’s polarity makes it an effective solvent for many ionic compounds.

1C.4 DISSOLVING 1C.4 DISSOLVING IONIC COMPOUNDSIONIC COMPOUNDS

Do NowTurn to page 75 and use the

chart: What mass of O2 can be

dissolved in 1500.0 g of water at 30.0 °C?

Objectives1. SWBAT define Saturated,

supersaturated, and unsaturated solutions.

2. SWBAT answer questions about solubility curves and practice reading and interpreting graphs.

3. SWBAT describe two separate steps required in the dissolving process;

4. SWBAT explain how water’s polarity makes it an effective solvent for many ionic compounds.

Dissolving ProcessDissolving ProcessIn your lab, you observed

Potassium Nitrate dissolving in water

This is a macroscopic phenomenon

Chemistry is concerned with what happens at the particulate level – atomic and molecular phenomenon, which cannot be observed easily

Dissolving ProcessDissolving ProcessFactors that contribute to

dissolving a solid material:◦Temperature◦Agitation◦Time

But how do the particles of solute & solvent interact to make dissolving happen?

Water’s RoleWater’s RoleWater is a polar

moleculeAlthough it is

neutral overall, it has an uneven distribution of electrical charge.

Partial positive region at one end

Partial negative region at other end

Water’s RoleWater’s RoleIt has a bent or

V-shapeThe Oxygen end

has greater concentration of electrons than the two Hydrogen ends

Water’s RoleWater’s RoleView “Molecular Views of Water”

Water’s RoleWater’s RolePolar water

molecules are attracted to other polar substances & to substances composed of electrically charged particles

Electrical attractions make it possible for water to dissolve many kinds of substances

Salt Dissolving in Water

Think about the ions & molecules interacting at different times.

Salt Dissolving in WaterSalt Dissolving in WaterQ. What forces

hold the ionic lattice together?

A. Opposing ionic charges

Salt Dissolving in WaterSalt Dissolving in WaterQ. Why do the

water molecules interact with ions?

A. Water’s molecular polarity allows it to interact with both positive & negative ions.

Salt Dissolving in WaterSalt Dissolving in WaterQ. What do the

dissolved ions have in common with each other?

A. They are all solvated – surrounded – by water molecules.

Salt Dissolving in WaterSalt Dissolving in WaterQ. How are the

dissolved ions different?

A. Positive H ends of H2O are aligned with negative Cl ions, and negative O ends of H2O are aligned with positive Na ions

Salt Dissolving in WaterSalt Dissolving in WaterQ. On the

particulate level, what would evaporating water imply for this system?

A. The crystal lattice would begin to reform with fewer water molecules to overcome the ion-ion attractive forces.

Water’s RoleWater’s RoleView “Modeling Matter: Attraction

Between Particles”Q. What factors influence whether or

not an ionic compound dissolves in water?

A. Properties of both solute & solvent, because dissolving involves competition among 3 types of attractions:◦Solvent – Solute◦Solvent – Solvent ◦Solute – Solute


Between Particles”Q. What factors influence whether

or not an ionic compound dissolves in water?

A. Properties of both solute & solvent, because dissolving involves competition among 3 types of attractions:◦Solvent – Solute◦Solvent – Solvent ◦Solute – Solute

Think-Pair-ShareGo to:http://www.sumanasinc.com/web

content/animations/content/propertiesofwater/water.html

And answer the following questions on the worksheet

Do NowWhat ions does salt dissolve into?Draw each ion solvated by water

molecules. (Make sure you draw the water molecules in the right direction!)

Objectives1. SWBAT practice reading and

interpreting solubility curves.2. SWBAT draw water molecules

and orient them in the correct direction to dissolve various substances.

Do Now Draw a calcium ion solvated by

water molecules.

Objectives1. SWBAT define solute

concentration.2. SWBAT describe and calculate

mass concentration (pph, ppm, and ppb).

3. SWBAT explain the relevance to environmental chemists


Between Particles”

1C.5 THE 1C.5 THE DISSOLVING DISSOLVING PROCESSPROCESS

Modeling Matter, p. 62

The Dissolving ProcessThe Dissolving ProcessView “Dissolving Ionic Compounds”View “Modeling Matter Ionic

Solutions

Do Now For a salt solution that is .56

ppm, calculate the amount of salt in 2,000 g of solution.

Do NowClean off your desk. Take out a calculator and

something to write with.

Objectives1. SWBAT define heavy metals,

green chemistry, regulatory limits, acids, bases, alkaline, and pH.

2. SWBAT describe the health concerns for Pb2+ and Hg2+.

3. SWBAT describe the pH ranges that affect the health of fish

1C.7 DESCRIBING 1C.7 DESCRIBING SOLUTION SOLUTION CONCENTRATIONSCONCENTRATIONS

Developing Skills, pp. 64 #1-5

1C.8 INAPPROPRIATE 1C.8 INAPPROPRIATE HEAVY-METAL ION HEAVY-METAL ION CONCENTRATIONS?CONCENTRATIONS?

Heavy MetalsHeavy MetalsMany metal ions are essential to our

health◦ Iron(II) Fe2+

◦Potassium K1+

◦Calcium Ca2+

Some “heavy-metal” ions are harmful.◦Masses are heavier than the essential metal

ions.◦Toxic: bind to proteins, preventing them from

performing their normal tasks◦Nervous system, brain, kidneys, liver, death◦Lead Pb2+

◦Mercury Hg2+

Do NowDraw a picture of 20 g lithium

fluoride dissolved in 100 grams of water

Draw a picture of 20 g lithium fluoride dissolved in 200 grams of water

Objectives1. SWBAT define heavy metals,

green chemistry, regulatory limits, acids, bases, alkaline, and pH.

2. SWBAT describe the health concerns for Pb2+ and Hg2+.

3. SWBAT describe the pH ranges that affect the health of fish

Heavy MetalsHeavy MetalsNot removed as waste as they

move through the food chainConcentrated in bodies of fish &

shellfish – even when present in low concentrations in surrounding water

Hard to detect in low concentrations

Difficult & costly to removeHow to prevent poisoning?Prevention: “Green Chemistry”

Lead Ions (PbLead Ions (Pb2+2+))Plumbum – Plumber – ancient Roman water

pipesPottery, automobile batteries, solder,

cooking vessels, pesticides, paints (primary ingredient in red paint that protects bridges & other steel structures from corrosion)

Leaded gasoline – phased out in the 1970s – was a better burning fuel. Soils around heavily traveled roads are still contaminated

Mercury Ions (Hg Mercury Ions (Hg 2+2+))Only metallic

element that is a liquid at room temperature

Hydragyrum – liquid silver or quicksilver

“silent” light switches, street lamps, thermometers, thermostats, fluorescent light bulbs, paints, antiseptics, fungicides, pesticides

During the 18th & 19th centuries, mercury compounds were used in the making of felt hats.

Ultimately, mercury poisoning caused symptoms such as numbness, staggered walk, tunnel vision, and brain damage, giving rise to the expression “mad as a hatter.”

Heavy MetalsHeavy MetalsA sudden release of a large amount of

a heavy-metal ion might cause a fish kill

It would depend on:◦what ion ◦ its concentration◦species of fish◦other factors

Is there a source of heavy metal ions along the Snake River within 15 km of Riverwood?

What concentration would be toxic?

1C.9 INAPPROPRIATE 1C.9 INAPPROPRIATE pH LEVELS?pH LEVELS?

pHpHpH scale reports: acid, bases, or

chemically neutralpH usually between 0 to 14

◦< 7 - acid (lower numbers, more acidic)◦= 7 - neutral◦> 7 - base/alkaline (higher numbers,

more basic)Change in 1 pH unit = 10X difference

Ex. Soft drinks = pH of 3 Lemon juice = pH of 2 Lemon juice is 10X more acidic than soft

drinks

Do NowDraw the pH scale and label the

following on it◦Weak acid◦Strong Base◦Strong Acid◦Neutral◦Weak Base

0 1 3 5 7 9 11 13 14

CharacteristicsCharacteristicsACIDSH+ in water

◦ HCl, H2SO4, H3PO4

Litmus: blue to redSour – Don’t taste!Conduct electricity

BASESOH- in water

◦ NaOH, Ca(OH)2

Litmus: red to blueBitter – Don’t taste!Conduct electricity

pH of Common pH of Common SubstancesSubstances

pH continuedpH continuedNeutral solutions (pH = 7) are neither

acids nor bases◦NaCl (table salt) is an ionic compound

that is neutral◦C12H22O12 (sugar) is a molecular

compound that is neutralRainwater is slightly acidic (pH ≈ 5.8)Both acids & bases effect living

thingsEPA requires drinking water be

between 6.5 to 8.5

pH continuedpH continuedToo low a pH in rivers, lakes, &

streams◦Impairs fish egg development – affects

reproduction◦Increases concentration of metal ions –

by leaning metal ions from surrounding soil – Al3+ can be toxic to fish in high concentrations

Too high a pH◦Can dissolve skin & scales

pH continuedpH continuedEPA requires pH of drinking water be

between 6.5 to 8.5Fish can tolerate a pH between 5.0 to

9.0Expert anglers try to fish in water

with a pH between 6.5 and 8.2pH of Snake River – on a normal day

– ranges from 7.0 – 8.0, nearly optimal for fishing

Could the pH on the Snake River near Riverwood have abruptly changed?

Do NowWhat were some of the acids

from yesterday’s lab?

What were some of the bases from yesterday’s lab?

Objectives1. SWAT explain the solubility of

molecular substance sin water and consider their role in the fish kills

2. SWBAT create a lab to test and design solubility of different items together.

1C.10 INAPPROPRIATE 1C.10 INAPPROPRIATE MOLECULAR MOLECULAR SUBSTANCE SUBSTANCE CONCENTRATIONS?CONCENTRATIONS?

Molecular SubstancesMolecular SubstancesIonic substances

are crystalline solids at room temperature

Ionic substances release ions when they dissolve in water

Molecular substances are found as solids, liquids, or gases at room temperature – state depends on strength of attraction among the molecules

Molecular substances remain as whole molecules when they dissolve in water

Molecular SubstancesMolecular Substances

What determines the solubility of a molecular substance in water?

Attraction of a substance’s molecules for each other compared to their attraction for water molecules

Distribution of electric charge within the molecules is a major factor

Molecular SubstancesMolecular SubstancesMost molecular compounds contain

atoms of nonmetallic elementsRemember, these atoms are linked

together by the attraction of one atom’s positive nucleus to another atom’s negative electrons

Molecular SubstancesMolecular SubstancesIf the differences in attractions

between the two atoms are big enough, electrons move from one atom to another, forming ions.

If the differences in attraction between the two atoms exist but are not that big, they may cause the electrons to shift around and become unevenly distributed.

The ability of an atom to attract electrons is known as its electronegativity.

Molecular SubstancesMolecular SubstancesShow “Solubility of Molecular Sub

stances”“Like Dissolves Like”Polar molecules dissolve in polar

solventsNonpolar molecules dissolve in

nonpolar solvents

Think-Pair-Share1. Draw a water molecule with

it’s partial charges.2. Explain why it’s polar.3. What molecular substances

would water dissolve with and why?

Concept ChartSolubility

Molecular Substances

Explain how it dissolves:



HomeworkYou must read part 1 of C.11

Solvents on pg. 72-74 (top)Write out the personal answers

to the 3 questions on the bottom of pg. 73

This REQUIRED for you to proceed with next week’s lab, and will count as 20% of your lab grade.

Do NowExplain why oil and water do not

dissolve in each other.

ObjectivesSWBAT create models of different

molecular substances.SWBAT demonstrate how water

molecules orient around ionic compounds.

SWBAT explain why polar and nonpolar substances can or cannot dissolve in each other.

Molecular SubstancesMolecular SubstancesWere dissolved molecular

substances present in the Snake River when the fish died?

If so, were they responsible for the fish kill?

Depends on what was present and in what concentrations

That depends on how each solute reacts with water’s polar molecules

1C.11 SOLVENTS1C.11 SOLVENTSInvestigating Matter, pp. 72-75

Do NowExplain why oil and water do not

dissolve in each other.

1C.12 1C.12 INAPPROPRIATE INAPPROPRIATE DISSOLVED OXYGEN DISSOLVED OXYGEN LEVELS?LEVELS?

Do NowWhy do fish need oxygen?

Objectives1. SWBAT describe the difference

between solubility of solids and gases.

2. SWBAT explain the metabolic changes of fish as temperature and dissolve oxygen change.

3. SWBAT describe factors that can change the amount of dissolved oxygen.

4. SWBAT complete yesterday’s lab.

Oxygen & Other GasesOxygen & Other GasesIonic & molecular

solids tend to have a higher solubility at higher temperatures

The opposite tends to be true for gases

Also, most gases are much less soluble in water than solids are – at any temperature

Oxygen & Other GasesOxygen & Other GasesIn addition to the temperature &

the type of solvent, the solubility of a gas also depends on gas pressure.

Is this relationship directly or inversely proportional?

GasesGasesSoda has extra CO2 forced

into it under high pressureWhen a can or bottle of

soda is opened, the solution is now supersaturated at the lower pressure, & some excess dissolved CO2 escapes as bubbles

The “flat” soda is still saturated with the gas

1.C. 13 1.C. 13 TEMPERATURE, TEMPERATURE, DISSOLVED OXYGEN, DISSOLVED OXYGEN, AND LIFEAND LIFE

Temperature & Dissolved Temperature & Dissolved OxygenOxygenDid the temperature of the Snake River

have something to do with the fish kill?

Temperature & Dissolved Temperature & Dissolved OxygenOxygenHow does a temperature change affect

fish?Cold-blooded: body temperatures rise

& fall with the water temperatureRise

◦ Increases metabolism◦ Eat more◦ Swim more◦ Require more dissolved oxygen◦ Also increases metabolism of other aquatic

organisms (i.e., aerobic bacteria) that compete with fish for dissolved oxygen

Temperature & Dissolved Temperature & Dissolved OxygenOxygen

Rise in temperature, decreases the amount of dissolved O2 in the water while it increases the fish’s need for it

A long stretch of hot summer days sometimes kills fish

Temperature & Dissolved Temperature & Dissolved OxygenOxygen

Hot, summer days are not always the cause

Many industries use water to cool their heat-producing processes, dumping the heated up water back into the rivers or lakes

Temperature & Dissolved Temperature & Dissolved OxygenOxygenCan too much dissolved oxygen

be a problem?When oxygen gas dissolves, so

does nitrogenWhen the total amount of

dissolved gas reaches between 110% to 124% of saturation (a supersaturated state), gas-bubble trauma may develop in fish

Temperature & Dissolved Temperature & Dissolved OxygenOxygenGas bubbles form in the blood

and tissues of fishO2 bubbles can be partially

utilized during metabolism, butN2 bubbles block the capillariesDeath within hours or daysPrompt dissection after death

can find gas bubbles in the gills

Supersaturation of water with oxygen & nitrogen can occur at the base of a dam or hydroelectric project, as the released water forms “froth,” trapping large quantities of air

Do NowExplain what happens to the

amount of dissolved oxygen as the temperature increases?

How about when the pressure increases?

Objectives1. SWBAT examine what happens

to fish when too much oxygen dissolves in the river.

2. SWBAT answer questions on section 1.c. to help study for their test on Thursday.

Lab Solubility ReviewPolar Substances dissolve other

__________ or ____________.

Non Polar Substances dissolve _______________.

Dissolving Substances (Lab)List several substances that will

dissolve in water and why….

Hexane is NON POLAR, list several substances that will dissolve in hexane.

Common Nonpolar substancesHexaneLamp OilPaint ThinnerFats

HomeworkPg. 83 #23-31, pg. 84 #33, 35

Do NowAt what temperature will a

saturated solution contain 40g KCl dissolved into 100g of water?

ObjectivesSWBAT answer multiple choice

and short answer questions on chapter 1.C. to help them study for their test tomorrow.

Temperature & Dissolved Temperature & Dissolved OxygenOxygenWhat caused the Riverwood fish kill?How will you decide what was the

actual cause?You will start by examining water-

related measurements collected by scientists & engineers on the Snake River

From these data & what you have learned in class, you will decide on the actual cause of the fish kill

1.C.14 DETERMINING 1.C.14 DETERMINING THE CAUSE OF THE THE CAUSE OF THE FISH KILLFISH KILL

Making Decisions, pp. 79-81

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