M I S S S H U E YC H E M C O M M

UNIT 1: WATER: EXPLORING SOLUTIONS

ESSENTIAL QUESTIONS

• What techniques can we use to purify water?• What are the physical properties of water?• Why do some substances readily dissolve in

water and others do not?• How does chemistry contribute to effective water

treatment?

ARTICLE REVIEW

• Fish Kill Triggers Riverwood Water Emergency

SECTION A: SOURCES AND USES OF WATER

• Uses of water:1. _________________________2. _________________________3. _________________________4. _________________________5. _________________________6. _________________________7. _________________________8. _________________________9. _________________________10. _________________________

A.4 WATER SUPPLY AND DEMAND

• Family of four uses 390 gallons daily.• Direct water use – volume that can be directly

measured.• Indirect water use – hidden uses of water that

you may never have considered.• Ex. Slice of pizza??Figure 1.12

A5. WATER USE IN THE US

• For each region in the US, name the greatest single use of water.• A. the east b. the south c. the midwest• D. the west e. alaska f. hawaiiExplain the differences in how water is used in the east and the west. Think about where most people live and where most of the nation’s factories and farms are located. What other regional factors help explain the general patterns of water use?List two factors about the weather, economy, or culture that could explain the greatest water use within each of these six U.S. regions.

A.6 WHERE IS THE WORLD’S WATER?

• 97% of the world’s water.1. Ocean2. Glaciers

PHYSICAL STATES OF WATER

• Gaseous state: water vapor• Liquid state: lakes, rivers, oceans, clouds, and

rain.• Solid state: ice

CITY WATER

• Surface water: water supply originated in a river or other body of water.• Ground water: water in a well.

RURAL WATER

• Aquifer: water-bearing layer of rock, sand, or gravel, then pumped to the surface.

A.8 RIVERWOOD WATER USE

• Pg.22• http://

www.youtube.com/watch?v=xxNfJLMNS4E&list=FLHywkjQDas46hk_l2QAeKaA&feature=mh_lolz

SCIENTIFIC METHOD

Hypothesis – testable statementcontrols – remain constantvariable – is changed

Model – explanation of how phenomena occur and how data or events are related.Theory – broad generalization that explains a body of facts or phenomena.

ACCURACY AND PRECISION

• Accuracy – close to the expected value• Precision – a number of measurements close to

each other.

What is more accurate?Graduated cylinderOrBeaker

SIGNIFICANT FIGURES

• Indicates how precise a measurement is.rule example1. Zeros between other nonzero digits are significant

a. 50.3 m has three sig figsb. B. 3.0025 s has five sig figs

2. Zeros in front of nonzero digits are not significant.

a. 0.892 kg has three sig figsb. 0.0008 ms has one sig fig

3. Zeros that are at the end of a number and also to the right of the decimal are significant

a. 57.00 g has four sig figsb. B. 2.000000 kg has seven sig figs

4. Zeros at the end of a number but to the left of a decimal are significant if they have been measured or are the first estimated digit; if not they are NOT significant.

a. 1000 m may contain from one to four sig figs, depending on the precision of the measurement, in this book it will be assumed there is one sig fig.

b. 20 m has one sig fig (scientific notation will indicated sig fig number)

RULES FOR CALCULATING WITH SIG FIGSType of calculation Rule exampleAddition or subtraction When measurements

are added or subtracted, the answer can contain no more decimal places than the least accurate measurement

97.3 + 5.85 --------- 103.15 103.2Round off

Multiplication or division

The final answer has the same number of sig figs as the measurement having the smallest number of sig figs.

123x 5.35------------- 658.05 658 Round off

SIG FIG PRACTICE

Perform these calculations following the rules for sig figs.a. 26 x 0.02584 = ?b. 15.3 / 1.1 = ?c. 782.45 - 3.5328 = ?d. 63.258 + 734.2 = ?

SI unit – measurements in science.

VolumeDensity – m/v

A sample of aluminum metal has a mass of 8.4g. The volume of the sample is 3.1 cm3. calculate the density of aluminum.

Dimensional analysis – math technique that allows you to use units to solve problems involving measurements.

SECTION B

• Article reading

• B.1 PHYSICAL PROPERTIES OF WATER• Matter – anything that occupies space and has

mass.• Physical properties: observed and measured

without changing the substance.• Density – mass of material within a given volume.• D = m/v

WATER PROPERTIES

• Freezing point – 0 C when liquid water forms a solid.• Aqueous solution – water-based solution.• Important aqueous solutions in your life:• ____________________• ____________________• ____________________

B.3 MIXTURES AND SOLUTIONS

• Mixture – when two or more substances combine and retain their individual properties.• Heterogeneous (suspension)• Homogeneous (solution)• Solute• Solvent

• Pg.30

B.4 PARTICULATE VIEW OF WATER

• Particulate level – at the level of its atoms and molecules.• Atoms – building blocks of matter.

• Element – matter made up of only one type of atom.• Compound – composed of the atoms of two or

more elements bonded together in fixed proportions.• Ex.

• Chemical formulas – representing compounds or elements, showing ratios of how they bond.• Ex. • Substance – element or compound with uniform

and definite compositions.• Molecule – smallest unit of a molecular

compound that retains the properties of that substance.

B.5 PICTURES IN THE MIND

• Macroscopic – large-scale, easily observed without microscopes or other tools.• Models – representations of atoms and molecules.• Pg.33 ques. 1-7

B.6 SYMBOLS, FORMULAS, AND EQUATIONS

• Chemical symbols – letters to represent element.• Periodic table of the elements – arrangement

of elements according to the number of protons.

COMMON ELEMENTSAluminum Al Hydrogen HBromine Br Iodine ICalcium Ca Iron FeCarbon C Lead PbChlorine Cl Magnesium MgCobalt Co Mercury HgCopper Cu Nickel NiFluorine F Nitrogen NGold Au Oxygen OPhosphorus P Potassium KSilver Ag Sodium NaSulfur S Tin Sn

WHAT ELEMENT IS THIS?

Kpotassium

WHAT ELEMENT IS THIS?

Alaluminum

WHAT ELEMENT IS THIS?

Brbromine

WHAT ELEMENT IS THIS?

Cacalcium

WHAT ELEMENT IS THIS?

Ccarbon

WHAT ELEMENT IS THIS?

ClChlorine

WHAT ELEMENT IS THIS?

CoCobalt

WHAT ELEMENT IS THIS?

FFluorine

WHAT ELEMENT IS THIS?

AuGold

WHAT ELEMENT IS THIS?

HHydrogen

WHAT ELEMENT IS THIS?

IIodine

WHAT ELEMENT IS THIS?

FeIron

WHAT ELEMENT IS THIS?

PbLead

WHAT ELEMENT IS THIS?

MgMagnesium

WHAT ELEMENT IS THIS?

HgMercury

WHAT ELEMENT IS THIS?

NiNickel

WHAT ELEMENT IS THIS?

NNitrogen

WHAT ELEMENT IS THIS?

OOxygen

WHAT ELEMENT IS THIS?

PPhosphorus

WHAT ELEMENT IS THIS?

AgSilver

WHAT ELEMENT IS THIS?

NaSodium

WHAT ELEMENT IS THIS?

SSulfur

WHAT ELEMENT IS THIS?

SnTin

WHAT IS THE ATOMIC NUMBER?

O – Oxygen8

WHAT IS THE ATOMIC NUMBER?

C – Carbon6

WHAT IS THE ATOMIC NUMBER?

H – Hydrogen1

WHAT IS THE ATOMIC NUMBER?

Au – Gold79

WHAT IS THE ATOMIC NUMBER?

N – Nitrogen7

B.8 ELECTRICAL NATURE OF MATTER

• Electrons – negatively charged particles• Protons – positively charged particles, in nucleus• Neutrons – neutral particles, in nucleus

B.9 IONS AND IONIC COMPOUNDS

• Ions – electrically charged atoms or groups of atoms.• Ionic compounds –

substances composed of positive and negative ions• Cation – positive ion Na+• Anion – negative ion Cl-• Polyatomic ion – ion

consisting of a group of bonded atoms

B.11 WATER TESTING

• Precipitate – insoluble material in water.• Qualitative test – looking at non numerical

descriptions.• Quantitative tests – numerical data.

• Ionic compounds• Metal + nonmetal

B.12 PURE AND IMPURE WATER

• Pg. 45• Gases in atmosphere dissolve in water, nitrogen,

oxygen, carbon dioxide• 46-47 Read

SEC. C INVESTIGATING THE CAUSE OF THE FISH KILL

• Solubility – substance that will dissolve in water.• Saturated – maximum quantity of a substance

that will dissolve in a quantity of water.• What effects solubility?

• Solubility curve – relationship between temperature and solubility

• Unsaturated solution – solution that contains less dissolved solute than the amount that the solvent can normally hold at that temperature.• Supersaturated solution – unstable solution

that contains more solute than could usually be dissolved at that temperature.• Ex. Rock candy (pg.55)

C.4 DISSOLVING IONIC COMPOUNDS

• Form ions in water• Polar molecule – electrons are not evenly

distributed throughout its structure.• Partial positive region and partial negative region.• Ex. water

DIATOMICS

Reactant and Products are shown in chemical equationsReactant are the substances that are used to make a chemical reaction               Products are substances produced by the reaction                Na + Cl --->   NaCl                reactant  --> products

Diatomic Molecules - some elements bond to themselves, like H2

GEN-U-INE diatomic molecules U should remember that the diatomic molecules all end in -GEN or -INE(or  H N F O I C B )       H2    N2   F2     O2  I2   Cl2   Br2

C.8 INAPPROPRIATE HEAVY-METAL ION CONCENTRATIONS?

• Essential Metal Ions:• Iron(II) Fe2+• Potassium K+• Calcium Ca2+• Magnesium Mg2+

Heavy-metal ions – atoms have greater masses than those of essential metallic elements, harmful to humans and other organisms. • Lead Pb2+ -bind to proteins in biological systems,• Hg2+ prevents proteins from performing their

normal task.

HEAVY METAL HARM

• Damage to the nervous system, brain, kidneys, and liver, which can even led to death.• They become concentrated within the bodies of

fish and shellfish.• Costly to remove• Hard to detect• Prevention: using alternate materials in industry.

Called Green Chemistry

LEAD IONS (PB2+)

• Latin name – plumbum• Plumber – water pipes in ancient Rome were

commonly made of lead.

• Used in:• Pottery, automobile electrical storage batteries, solder,

cooking vessels, pesticides, and paints

Many were replaced with iron, copper or plastic materials.1970s lead was added to gas to produce a better-burning automobile fuel. Released in atmosphere.

MERCURY IONS HG2+

• Liquid at room temp• Latin name = hydrargyrum, quicksilver or liquid

silver• Uses:• Electrical conductor, thermometers, thermostats, hats,

light bulbs, pesticides

• Vapor is hazardous, absorbed through skin

CHEMICAL POSTER

C.9 INAPPROPRIATE PH LEVELS

• pH – measure and report the acidic, basic, or chemically neutral character of a solution.• Range = 0---14• Neutral = 77> acidic7<basic (alkaline solutions)1pH unit = tenfold difference in acidity or alkalinitypH 3 soft drinks, pH 2 lemon juiceLemon juice is 10 time more acidic than soft drinks.

LITMUS PAPER

• Indicator to show level of acidity or alkalinity.• Blue – basic• Red – acidic• Acidic and basic solutions conduct electricity.• What does this tell you?• Ions present in the solution.• Acids – release H+ ions • Bases – release OH- ions

NEUTRAL SUBSTANCES

• Sucrose, sodium chloride solutions = neutral• Low pH in streams• Fish-egg development is impaired• Increase the concentrations of metal ions by leaching

metal ions from surrounding soil.

High pH in streams• alkaline solutions are able to dissolve organic

materials, including skin and scales

EPA REQUIREMENTS

• Drinking water be within the pH range of 6.5 – 8.5• Fish can tolerate 5.0 – 9.0

• Did the pH change to kill all the fish?

C.10 INAPPROPRIATE MOLECULAR SUBSTANCE CONCENTRATIONS

• Molecular substances – composed of molecules not ions.

• Molecular substances can be harmful for aquatic life.• Examples: ethanol C2H5OH, succinic acid C4H6O4,

carbon dioxide CO2, oxygen gas O2• What determines the solubility of a molecular

substance in water?• Distribution of electrical charge within molecules.• Electronegativity – ability of an element’s atoms

to attract shared electrons when bonding within a compound. causes e- to be unevenly distributed among the atoms.

POLAR MOLECULE

• Negative and positive side of a molecule.• “like dissolves like”• Polar dissolves polar• Nonpolar dissolves nonpolar• Ex. Oils, soaps soap attracts oils

C.11 SOLVENTS

• Soluble – will dissolve• Insoluble – will not dissolve

C.12 INAPPROPRIATE DISSOLVED OXYGEN LEVELS?

• As temperature goes up less oxygen is dissolved.• Gas solubility in water is directly proportional to

the pressure of that gaseous substance on the liquid.• Increase in water temperature affects fish by

decreasing the amount of dissolved oxygen in the water and by increasing the oxygen consumption of fish.