1b. looking at water & its contaminants

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1B. Looking at 1B. Looking at Water & Its Water & Its Contaminants Contaminants Learning more about the chemistry of water and how substances interact with water

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1B. Looking at Water & Its Contaminants. Learning more about the chemistry of water and how substances interact with water. Do Now:. The teacher has two substances on the desk (A and B). Are they the same? Venture a guess as to what you think they are. - PowerPoint PPT Presentation


  • 1B. Looking at Water & Its ContaminantsLearning more about the chemistry of water and how substances interact with water

  • Do Now:

    The teacher has two substances on the desk (A and B). Are they the same? Venture a guess as to what you think they are.Explain why beetles have the ability to walk on water. (Take a look at the picture below)

  • Objectives:SWBAT: Learn the physical properties of water & compare to another liquid.Use a balanceRead a grad. cylinderMake and record measurementsRecord observations


  • Water has Physical PropertiesMatter can be distinguished by its properties.Physical properties are those that can be observed and measured without changing the chemical makeup of the substanceCan you think of some?Write down at least 3 physical properties of water that you can think of.*

  • Physical Properties of water:Color colorless, clearOdor - odorlessDensity = mass/ volume Temperature dependentFreezing point = 0CBoiling point = 100CSurface tension

  • Pure WaterPure water is water with absolutely nothing else dissolved or suspended in itProperties of pure waterClearColorlessOdorlessTasteless *

  • Lab DemoMake and record proper observations for each demonstration.

  • Do Now Draw a graduated cylinder, with the appropriate volume markings and layer the liquids according to density.5 mL liquid A, Density = 3.4g/ml2 ml liquid B, Density = 0.90/ml3 ml liquid C, Density = 1.00g/ml

  • Do Now What physical property of water explains the sheeting action under the swimmers right arm?

  • ObjectivesSWBAT compare and contrast surface tension between water and alcoholSWBAT define matter and discuss the physical properties of water. SWBAT calculate density

  • Surface Tension

  • Surface Tension:Forces of attraction between the hydrogen atoms in water that keep the atoms close togetherAlmost as if they form a barrier and make the water molecules stick togetherHeld together by cohesive forces.Responsible for creating a meniscusResponsible for spherical water dropsDoesnt stick to wax (on cars etc.)Adheres weakly, so molecules stick together.

  • Molecular view of surface tension

  • HWPg 50 (1-4)

  • Do NowDraw:A) a water molecule (H2O)B) 2H2O

  • ObjectivesSWBAT identity the number of different compounds in a substance or mixtureSWBAT draw different mixtures and answer questions related to those pictures

  • Particulate LevelTo understand the macroscopic (large scale & readily observed) properties of water, you have to understand waters behavior at the particulate level the level of small particles the level of atoms and molecules*

  • SubstancesAtoms building blocks of matterElements made of one kind of atomRepresented by symbols (H, O, Ne) & sometimes formulas (H2, O2)Molecules made of atoms joined together atoms can be the same or differentCompounds made of different elements combined togetherRepresented by formulas (H2O, KCl)*

  • MODELS:REPRESENTATIONS OF ATOMS & MOLECULESThese pictures are one kind of model (space filling model).*

  • Drawing ModelsSample Problem: Draw a model of two gaseous compounds in a homogeneous mixture.What do you need to know to draw your model?What is a homogeneous mixture?What might a gaseous compound look like?How many compounds are in this mixture?There is more than one drawing possible.*

  • PracticeDescribe the picture:

    1. What type of mixture is this?2. How many compounds?3. What state of matter?

  • Drawing ModelsWhich of the following drawings best represents a homogeneous mixtures of two gaseous compounds?*

  • Drawing ModelsThe best answer is b.* 2 types of molecules are uniformly mixed Atoms are colored to represent different elements Not homogeneous 3 different compounds, not 2b & c are space-filling models. a is a ball-and-stick model. Both are acceptable.

  • Drawing ModelsWork in pairs on WKST U1B.5- Modeling Matter


  • Do NowWhat is a solution?

    Describe the difference between a heterogeneous and homogeneous mixture

  • ObjectivesSWBAT review the differences between types of mixtures.SWBAT create a concept chart of substances and mixtures and provide examples of each.SWBAT differentiate between symbol, element, compound, and molecule.



  • A. Matter FlowchartMATTERCan it be physically separated?Homogeneous Mixture(solution)Heterogeneous Mixture



  • Substances Dissolve in WaterAqueous solutions water based solutionsSOLUTE- substance that is being dissolvedSOLVENT- substance that dissolves the solute (usually water, in aqueous solutions it is water)


  • SolutionsAll solutions are homogeneous mixtures

    A solute dissolves in a solvent to make a solutionSolutions are clear but not necessarily colorlessA conductivity test indicates the presence of dissolved charged particles*

  • Substances Dissolve in Water


    SampleSoluteSolventSalt WaterCoffeelemonade

  • Matter is divided into a mixture or a substanceSubstance:Definite composition, not physically able to separate

    Mixture:two or more substances coming together but keeping their individual propertiesFoul Water was a mixture of water, used coffee grinds, oil, garlic powder, salt

  • Types of MixturesHomogeneous Mixture:Composition is the same or uniform throughout

    Heterogeneous Mixture:Composition is not the same or uniform throughout.

  • 2 Types of Heterogeneous MixturesSuspension heterogeneous mixture containing large, solid particles that can settle out or be separated by filtration

    Colloid heterogeneous mixture containing particles too small to settle out cloudy Tyndall effect*

  • Types of SubstancesElements:One type of atom

    Compounds:Two or more types of atoms chemically bonded together

  • A. Matter FlowchartExamples:graphitepeppersugar (sucrose)paintsoda

  • A. Matter FlowchartExamples:graphitepeppersugar (sucrose)paintsoda

    elementhetero. mixturecompoundhetero. mixturesolution

  • Mixtures(variable composition)Homogeneous Solutions evenly distributedHeterogeneousnot evenly distributed

  • Diatomic ElementsHydrogenNitrogenOxygenFluorineChlorineBromine Iodine

    There are 7 diatomic elements

    These atoms are never alone, if they are the pair up with the same atom

  • C. MixturesExamples:mayonnaisemuddy waterfogsaltwaterItalian salad dressing


  • Do NowFill in table on worksheet Unit1B4,6&9

  • ObjectivesDistinguish between symbols, chemical formulas and equationsDetermine the number of protons, electrons and neutrons in an atom

  • Symbols, Formulas, & EquationsThe international language of chemistry includes symbols, formulas, & equations.Symbols are like letters.Formulas are like words.Equations are like sentences.*

  • The lettersSymbols Elements Elements are organized on the Periodic Table of ElementsEach element is represented by a symbolCapital letterCapital letter & lower case letterFind some of these symbols on the Periodic Table.*

  • The Periodic Table of Elements contains much more useful information than just symbols.

    You will be learning more about this table throughout this course.People use aluminum to make a variety of products, including foil, cans, & lightweight construction materials.*

  • Silicon has properties that lie between those of metals and nonmetals. It is classified as a metalloid. One of its primary uses is in electronic devices.*

  • Sulfur is a nonmetal used in products such as fungicides and rubber of automobile tires.*

  • The wordsFormulasFormulas represent specific chemical substances.

    Formulas are made of symbols.

    Formulas may include subscripts.

    A subscript refers back to the symbol immediately before it. A 1 is understood & not written.*

  • ExamplesCO1 carbon & 1 oxygenCO21 carbon & 2 oxygensNH31 nitrogen & 3 hydrogensH2O2 hydrogens & 1 oxygenH2SO42 hydrogens, 1 sulfur, & 4 oxygens

  • Diatomic ElementsMost elements exist as individual atoms and are represented with symbols.Some elements exist as 2 bonded atoms of the same element.For example, hydrogen is a diatomic gas, so is always written as H2 when it is an uncombined element.*

  • The sentencesEquationsEquations give the details of chemical reactionsChemical reactions involve the breaking & making of chemical bonds, causing atoms to be rearranged into new substances.The new substances have different properties from those of the original materials.*

  • The sentencesEquationsThe original substances (reactants) are written first. Then, an arrow points to the new substances that are made (products).reactants productshydrogen + oxygen water

    2H2 + O2 2H2ONote that this equation is balanced. The total number for each kind of atom is the same for both reactants & products. *

  • Oxygen

    (number of protons)(and number of electrons if neutral)(number of protons and neutrons)(Oxygen)Atomic NumberAtomic MassElementSymbol

  • Practice ProblemsComplete the missing information and include the number of protons, neutrons, and electrons. Worksheet- Unit 1 B.7 part 2- Using the Periodic Table

  • CompleteWorksheet Unit1B7 Worksheet Unit1B7 part 2

  • HWPg 50-51 (5-18)

  • Do Now:Pg 51 (19-20) &Complete the table below:

    Element/ NameAtomicNumberAtomic Mass# protons# electrons# neutronsNa________W________Au________

  • ObjectivesSWBAT draw out Lewis Diagrams of different atomsSWBAT identify ions as cations and anions and be able to determine the formula for ions and be able to name them.SWBAT work in groups to answer questions as a conclusion to activity

  • Parts of the AtomProton- In nucleus, positive charge and a mass of 1Neutron-In nucleus, neutral charge and a mass of 1Electron-Outside nucleus, negative charge and no mass

  • Complete the chart

    Part of AtomChargeMassProtonNeutronElectron

  • So if this is an atom What makes atoms different?How is carbon different from oxygen?Different numbers of protons

  • Rubbing a balloon against your hair results in static electricity.

    Clothes taken out of the drier often show static cling.

    The shock that you sometimes receive after you walk across a rug & touch a doorknob is another example of matters electrical nature.

    What causes these phenomena?

    Static cling is best seen when the humidity is low.*

  • Attraction & RepulsionThe electrical properties of matter can be summarized as follows:

    What are these positive and negative particles?*

  • Subatomic ParticlesEvery neutral (uncharged) atoms contains an equal number of positively charged protons (+) and negatively charged (-) electrons.# of (+) protons = # of (-) electronsPositive-Negative attractions between the protons in one atoms the electrons in another atom hold atoms together in bonds.Most atoms also contain neutral particles having no charge (0) called neutrons.


  • Lewis Dot StructureValence Electrons: outermost electrons Electron Configuration:

    Energy LevelMAX. # of electrons1st 22nd 83rd84th18

  • Determining approximate placement of electrons Chlorine (atomic #_____)# protons = _____# electrons = _____Outermost energy level: _________

    # of valence electrons: __________

    Energy LevelMAX. # of electrons1st 2nd 3rd4th

  • Lewis Dot Structure:

  • Practice:

    Draw the Lewis Dot Diagrams for the following Atoms:



    FWorksheet: Unit 1 B.9 Valence Electrons

  • Ions and Ionic CompoundsRecall: Molecules make up one kind of compound.Ions make up another kind of compound.Ions are electrically charged atoms (or groups of atoms).Ions are formed when neutral atoms gain or lose electrons.*

  • IonsIons are electrically charged atoms (or groups of atoms).Ions are formed when neutral atoms gain or lose electrons.*

  • IonsRecall: What charge do electrons carry?NegativeWhen atoms gain negative electrons, they form negative ions.When atoms lose negative electrons, they form positive ions.*

  • IonsFor example, sodium (Na) is # 11 on the Periodic Table.It has 11 (+) protons and 11 (-) electrons.If it lost 1 (-) electron, it would have 11 (+) protons and 10 (-) electrons.It has one more proton than electrons, so it has a charge of -1.The symbol for a sodium ion is Na1+ or just Na+. (The 1 is understood.)*

  • IonsFor another example, chlorine (Cl) is # 17 on the Periodic Table.It has 17 (+) protons and 17 (-) electrons.If it gained 1 (-) electron, it would have 17 (+) protons and 18 (-) electrons.It has one less proton than electrons, so it has a charge of +1.The symbol for a chloride ion is Cl1- or just Cl-. (The 1 is understood.)*

  • Do Now (day 7)List the number of protons, electrons, and neutrons in each ion O2-H+F-Do any of these atoms have complete valence shells?

  • ObjectivesSWBAT determine the formulas for ionic compoundsSWBAT name different ionic compounds

  • Ionic CompoundsOppositely charged ions connect together to form ionic compounds.For example, sodium ions (Na+) connect to chloride ions (Cl-) to make sodium chloride (NaCl), or table salt.*

  • Sodium chloride consists of an equal number of positive and negative ions arranged in a 3-dimensional network called a crystal.A scanning electron micrograph shows the cubic structure of NaCl crystals.*

  • A space-filling model of NaCl provides information about how the individual sodium ions & chloride ions are arranged within the salt crystal.What else does this model suggest about the sodium and chloride ions or sodium chloride?*

  • If an ionic compound dissolves in water, the individual ions would separate from each other and spread out throughout the water.

    To show that they were now in an aqueous solution, an (aq) would be added after the symbols for the ions.

    Na+(aq) Cl- (aq)


  • More about IonsCation positive ion

    Anion negative ion

    Monoatomic ions (or monatomic)

    Polyatomic ionsNa+,


    Na+, Cl-, Mg2+, O2-, Al3+, N3-

    NH4+, CO32-, SO42-, PO43-*

  • Common IonsSee text p. 40 for a list of common ions.*

  • Practice:Find trends on the periodic tableWorksheet # Unit 1 B.9 part 2 Lewis Dot Structures

  • Formulas for Ionic Compounds2 Rules for Writing Formulas for Ionic Compounds

    1. Cation first, then anion

    2. Correct formula will be neutral, with the fewest number of each ion needed to make the total electrical charge zero

    No charges are shown in the formula.*

  • Practice ProblemsNaCl One Na1+ and one Cl1- cancel each other out.+1 + -1 = 0CaCl2One Ca2+ needs two of the Cl1- to cancel it out.+2 + -1 + -1 = 0Note: Negative monoatomic ions change their ending to ide.Examples above are sodium chloride and calcium chloride.

  • Formulas Containing Polyatomic IonsFormulas for compounds containing polyatomic ions follow the same rulesIf a subscript is needed, it follows the entire polyatomic ion, which is enclosed in parenthesesFor example, the calcium ion has a +2 charge, and the nitrate ion has a -1 charge*

  • Formulas Containing Polyatomic IonsFor example, the calcium ion has a +2 charge (Ca2+), and the nitrate ion has a -1 charge (NO31+). Two nitrate ions are needed to balance out the charge on one calcium ion.The formula for calcium nitrate is: Ca(NO3)2. No charges are shown in the formula.Polyatomic ions do not change their endings.*

  • Naming Ionic Compounds1. Name the cation, then the anion2. Have the last few letters changed to ide (monoatomic ions only)

    Ex. KF, potassium fluoride

    Ex. Ca(NO3)2, calcium nitrate

    Practice Worksheet Unit 1B.9 & B.10 Ion supplement

  • Write the formula and name the following ionic compounds

    1. Ca2+ Br-2. PO43- Ag+ 3. CO32- NH4+ 4. Al3+ NO3-

    What does the word ionic mean?

  • Practice:Worksheet (Unit 1B.9 part 3)

    Study for quiz

  • IB.11 WATER TESTINGday10*

  • Do NowExplain what charge the following items typically carry and WHY!LithiumChlorineCalciumDraw the Lewis Dot diagram for Li+.Draw a picture of a heterogeneous mixture of elements X and B.

  • Objectives1. SWBAT start to review for the test by going over the answers review questions.2. SWBAT read and think critically about the Riverwood Fish Kill.3. SWBAT create 2 possible hypothesis about the Riverwood fish kill.


  • Pure vs. Clean WaterIn the U.S., we all have access to abundant, low cost, clean, but not pure waterEven if the cost was not prohibitive, it would be impossible to have 100% pure water. Atmospheric gases (e.g., O2, N2, CO2) will always dissolve in the water to some extent.


  • HOW DO YOU NARROW DOWN THE DATA TO GET THE ANSWER?The cause of the fish kill may be related to something suspended in or dissolved in the water. What might it be?*

  • Chemistry at WorkTo learn about careers that require knowledge about what you are learning about in class right now, read text pp. 48-49, Environmental Cleanup: Its a Dirty Job But Thats the Point


  • ConcernsDissolved oxygen (DO) levels will testMicroorganisms none presentDissolved matter must consider amounts & effect of temperature on solubility will testSuspended particles will testOther InformationNo illness water conservation tips more water trucked in 3 day crisis expected

  • Now what?Water experts agree that the fish kill was caused by something either dissolved or suspended in the Snake River.How can you determine the exact cause?Knowing properties of water & properties of substances that may be found in it will help.Knowing language of chemistry will help you communicate your findings.*

    Colloid is the famous Tyndall effect (e.g. the light shining thru glass)*