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Lesson 2.2: Molecules, Compounds and Mixtures Learning Target: I can describe what happens when more than 1 atom comes together. Vocabulary: compound; mixture, heterogeneous, homogenous Warm Up: Complete Socrative Assessment. Copy errors and confusions. Teaching: Review LT; Vocabulary; Socrative Results Possible Misconception: If there were a mixture of water and salt in a beaker, could you separate the water from the salt? The Task: 1. Take notes on the topic by copying information from the guided notes sheet. **See pages 2-5 of this

document 2. “Check Your Understanding” **See page 6 of this document 3. “Marshmallow Molecules” assignment **See pages 7-8 of this document

b. Page 7 includes the assignment directions c. Page 8 includes a self-assessment opportunity for you to check your work

4. Complete the "Compounds and Mixtures" assignment **See pages 9-10 of this document 5. Investigating Substances in the Chemical Reactions Sim **See page 11 of this document 6. Can substances change into different substances? **See pages 12-13 of this document 7. Synthetic Materials: Making Substances in the Lab**See page 14 of this document 8. Enrichment: Finding Chemical Reactions**See page 15 of this document salt can be dissolved using water and later evaporated. Summarize: Check your answers

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Learning Target(s): I can describe what happens when more than 1 atom comes together. The particles in an element, molecule, compound and mixture look different. Element: a substance that is made of 1 kind of atom Aluminum Atom An Element: Many Atoms

Pure elements are made up of all 1 kind of atom. Every atom will have the same number of protons. The atoms in an element are NOT bonded to one another. Notice the 2nd picture, there are a bunch of identical atoms just sitting next to each other. Elements have atoms that are chemically the same.

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Sometimes molecules are shown by showing where their outer electron layers are overlapping. (the first picture of oxygen and ozone) Sometimes molecules are shown by drawing them as balls stuck together. (the second picture of oxygen and ozone) Sometimes molecules are shown by drawing them as balls connected by sticks. The balls are the molecules and the sticks are the bonds holding them together. Notice how in both examples, there is more than one atom that is connected in some way. This is different than the element that did not have the atoms connected.

Oxygen Oxygen

Molecule: more than one atom bonded together Elements bond together when they share or transfer their outer shell electrons (valence electrons) If you look at the particles in a substance, there are many ways that a molecule can be shown. Below are a few examples. Oxygen (O2)

Ozone (O3)

Molecules can have more than one element. Sugar (C6H12O6)

Glucose has carbon, hydrogen, and oxygen atoms bonded together. Because there is more than one kind of atom, it is a molecule. Molecules can be made up of more than one of the same kind of element or of more than one different kind of element. You can tell this because there is more than one chemical symbol (C, H, and O). Each chemical symbol represents a different element. You can also often tell there are different molecules because the color or shading of the “balls” are different to show they are different kinds of atoms. The small numbers are called subscripts. These tell how many atoms of each element are bonded together. In C6H12O6, there are 6 C’s (carbon atoms), 12 H’s (hydrogen atoms), and 6 O’s (oxygen atoms).

Oxygen

Oxygen Oxygen

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Compounds: More than one different element bonded together Water (H2O)

Carbon Dioxide (CO2)

Sodium Chloride or Salt (NaCl)

All compounds are also molecules! (But not all molecules are compounds.)

Na Cl

Water, H2O, has two hydrogen and one oxygen atom. It is important to draw it in a triangle shape. You can tell it is a compound because there are two different chemical symbols (H and O). You can also tell it is a compound because there are two different colored/shaded balls that are connected by a bond.

Some compounds have double bonds. This means that there are more outer electrons being used to make the bond. The two lines between the oxygen and carbon atoms means carbon dioxide has a double bond. Notice again that there are two different elements involved so it is a compound.

A salt is a kind of compound. We are familiar with table salt, but there are many kinds of salts. They are typically formed between an alkali metal and a halogen. Notice again that there are two different kinds of elements, Na and Cl. This makes it a compound. Each new capital letter in the chemical symbol means it is a new element.

Carbon dioxide (CO2) is a molecule and a compound. Because there is more than one atom bonded together it is a molecule. Because the two atoms are different (notice the shading of the balls is different), it is also a compound.

Oxygen (O2) is a molecule. It is not a compound. Because there is more than one atom bonded together it is a molecule. Because the two atoms are the same (notice the shading of the balls is the same), it cannot be a compound.

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Mixtures have multiple molecules that are mixed together, but not bonded together. Notice in the beaker of salt water to the right that there are salt molecules and water molecules, but they are not connected together. Salt water is a solution. It has one thing dissolved into another. Solute- the “thing” that gets dissolved Solvent – the “thing” that does the dissolving Solute - the thing that gets dissolved

Mixtures: A mix of compounds and molecules that can be separated by physical means (ex. By sifting/straining, magnets, dissolving, evaporating, etc) Salt Water (NaCl dissolved in H2O)

There are two types of mixtures. Heterogeneous: mixtures that are not the same throughout Ex: pizza, cookie dough, Italian dressing Homogeneous: mixture that is the same throughout Ex: air, tree sap, Mountain Dew, tap water Oxygen, Oxygen, and Air

This is oxygen the element. It is not bonded or mixed with any other atoms.

This is oxygen (O2) the molecule. It is bonded with another oxygen atom. This is the oxygen we breathe. This is the oxygen that we use during cellular respiration and that plants produce during photosynthesis.

Air is a mixture. There are many molecules mixed together but not bonded together. Notice that Oxygen (O2) is one of these molecules but it is not the only molecule in air. IMPORTANT: Oxygen is NOT air!!!!

Methane <1%

Atmosphere (Air) Gas Mixture

Nitrogen 78%

Oxygen 21%

Water Vapor <1% Carbon Dioxide <1%

Helium <1%

Neon <1%

Argon <1%

Krypton <1%

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Check Your Understanding: Look at the particles of the following substances. Determine if it is an element, compound or mixture.

1. Pure Gold (Au) 6. Nitrogen

2. Sugar (C6H12O6) 7. Ammonia (NH3)

3. Kool Aid 8. Silver (Ag)

4. Mystery Substance 9. Carbonic Acid (H2CO3)

5. Hydrogen Peroxide (H2O2) 10. Air

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Marshmallow Molecules LT: I can create models to describe how the particles in an element, molecule, compound, and mixture compare.

1. In this activity, the different colored marshmallows represent atoms and toothpicks represent bonds between atoms. Each element will be color coded and should be represented correctly in each section: Oxygen = blue; Carbon = red; Chlorine = purple; Hydrogen = yellow; Sodium = green

2. Divide your paper into four sections as shown:

3. In the Elements section of the paper, glue on one oxygen, carbon, chlorine, hydrogen, and sodium atom (marshmallow). Under each marshmallow, label it with its element name.

4. Using marshmallows and toothpicks, create the following items: **Be sure to reference the notes pages so that you use the correct number and type of atoms and represent the correct number and shape of bonds. a. Hydrogen diatom (H2): occurs when one hydrogen atom bonds to another hydrogen atom b. Oxygen diatom (O2): is unique because it is formed with a double bond. There are four outer shell

electrons being shared. c. Water (H2O) d. Carbon dioxide (CO2) e. Methane (CH4) f. Salt water

5. Draw and label each model in the appropriate section of the 4-section chart. Briefly describe your

reasoning for placing the item in the section of the chart. If an item belongs in more than 1 section, redraw the item in the other section(s).

6. Respond to the following prompts: a. Which section of the chart did not have any toothpicks? Why? b. If you were looking at the particles of a molecule, what is one thing you could you see that you would

not see in a compound? c. In the mixture section, should the water and the salt be connected with a toothpick? Explain.

Elements

Molecules

Compounds

Mixtures

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Check Your Work: a. Hydrogen diatom (H2): occurs when one hydrogen atom bonds to another hydrogen atom.

A yellow marshmallow connects to another yellow marshmallow with a small toothpick.

b. Oxygen diatom (O2): is unique because it is formed with a double bond. There are four outer shell electrons being shared. A blue marshmallow connects to another blue marshmallow with two small toothpicks to show a double bond.

c. Water (H2O): is formed when one oxygen atom bonds with 2 hydrogen atoms. As you read in the notes page, a water molecule is in the shape of a triangle with the oxygen in between the hydrogen molecules. A triangle shape is made with 2 yellow marshmallows placed on two sides of a blue marshmallow using one small toothpick on each side. There should not be a toothpick that connects the two yellow marshmallows.

d. Carbon dioxide (CO2): is formed when a carbon atom is double bonded to two oxygen atoms. There is

1 blue marshmallow on 2 opposite sides of a red marshmallow. This molecule should have marshmallows all in a straight line using 2 toothpicks for each bond.

e. Methane (CH4): is formed when one carbon atom bonds to four hydrogen atoms. The key is that the

carbon is connected to each of the hydrogen atoms. Four small toothpicks are stuck into a red marshmallow (one on each side). It should look like an x or a + sign. A yellow marshmallow is stuck to the end of all of the toothpicks.

f. Salt water: occurs when salt dissolves in water. These molecules mix, but to not bond together. To make a salt molecule (NaCl) a green marshmallow is connected with a small toothpick to a purple marshmallow. The salt molecule and the water molecule are placed next to each other but are not connected.

Remember: If my item is made of only 1 kind of atom, it is an element. If my item is made of more than 1 atom bonded together, it is a molecule. If my item is made of more than one different element bonded together, it is a compound. ***All compounds are also molecules! (But not all molecules are compounds.) If my item is made of multiple molecules that are mixed together but not bonded together, it is a mixture.

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Name:________________________________ Date: ________________ Class: __________ #: __________ Comparing Compounds and Mixtures LT: I can compare properties of compounds and mixtures. Procedure:

1. Collect the following substances- granular sugar, rubbing alcohol, and salad oil. 2. Observe the color, appearance, and state of each substance. Note the thickness or texture of each

substance. Record your observations on the table below. 3. Stir a spoonful of each substance into separate glasses of tap water and observe. Record your

observations in the table below. Data and Observations:

Substance Sugar Rubbing Alcohol Salad Oil

1. Color

2. Appearance

3. State

4. Thickness/texture

5. In water

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Analysis: 1. Compare the different properties of the substances. How do they compare before and after mixing?

2. The chemical formulas for each substance are written below:

Sugar: C12H22O11 Alcohol: C2H6O Oil: C18H34O2

Describe how the compounds above compare (in their elements and proportions).

3. After adding each compound to water, describe how each mixture compares. Do they appear as heterogeneous or homogenous mixtures?

4. If there were a mixture of sand and salt in a beaker, how would you separate the sand from the salt? The Enrichment: I can plan an investigation to demonstrate that mixtures are combinations of substances that can be separated by physical means. Task: Develop and carry out a procedure for separating a mixture of sand, salt, iron filings, and marshmallows by physical means.

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InvestigatingSubstancesintheChemicalReactionsSimLT:Icanuseadigitalsimulationtoinvestigatesubstancepropertiesandatomicmodelsinordertodeterminethatdifferentsubstancesaremadeupofdifferenttypesandnumbersofatomsarrangedindifferentways. Atoms are too small to see. Scientists rely on models to study things that are too small (or too large) to see. The Chemical Reactions Simulation can help us learn more about the atoms that make up various substances. The Simulation is a scientific model. Although this model is different from real life, it is accurate in many ways. We know that different substances have different properties. To learn more about why this is the case, we are going to use the Chemical Reactions Sim to investigate different samples at two scales: the macroscale that is visible to us, and the much smaller atomic scale. This will help us learn more about atoms and what they tell us about substances and their properties.

1. ExploretheChemicalReactionsSim:https://apps.learning.amplify.com/chemicalreactions/•testoneortwosubstancesatthesametime.•turnontheViewAtomicScaletoggletoseethesubstancesattheatomicscale.•turnonViewPropertiestoggletoviewsomeofthepropertiesofsubstances.Usethefollowingsentencestarterstodescribeyourthoughts:

•Inotice/observe...•Ithinkthisisimportantbecause...•Iwonder...

2. Withyourpartner,comparetheatomic-scalemodelsofthethreesamplesshownbelow.

Drawanddescribehowthesemodelsaresimilarandhowtheyaredifferent.

3. Basedontheatomic-scalemodelsofthesamples,recordoneofthefollowingclaimsyouthinkisbest:

Claim1:Allthreesampleshavethesameproperties.Therefore,theyarethesamesubstance.Claim2:Twosampleshavethesameproperties.Therefore,theyarethesamesubstance.However,onesamplehasadifferentsetofproperties.Therefore,thissampleisadifferentsubstance.Claim3:Allthreesampleshavedifferentproperties.Therefore,theyaredifferentsubstances.

4. FindthesubstancesrepresentedbythesemodelsintheChemicalStockroommodeoftheSim.

a. Observeandrecordtheirproperties.b. DoestheevidencefromtheSimsupporttheclaimthatyouchose?c. WhatevidencedidyoufindintheSimtosupportyouranswer?

5. Completethefollowingprompts:BasedonmyobservationsintheSim,Ithink:

d. sample1andsample2are-thesamesubstancewiththesameproperties. -differentsubstanceswithdifferentproperties.

e. sample1andsample3are

-thesamesubstancewiththesameproperties. -differentsubstanceswithdifferentproperties.f. sample2andsample3are

-thesamesubstancewiththesameproperties. -differentsubstanceswithdifferentproperties.

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Cansubstanceschangeintodifferentsubstances?LT:Icancollectdatafromaninvestigationanddigitalsimulationinordertoexplainifsubstancescanchangeintodifferentsubstances.InitialObservations1.Donotmixanyliquidsyet.Nevertasteorsmellanything.2.Recordthepropertiesofeachsubstanceinthedatatable(“Beforecombining”section).Reminder:Propertiesarethingssuchascolor,texture,andphaseatroomtemperature.CombiningSubstances3.Slowlypourtheentirecontentsofeachcupintothecuplabeled“product.”4.Donotstirtheproduct.It’simportantthatyounotmovethecup.5.Observewhathappensintheproductcupforatleastoneminute.6.Recordthepropertiesofthesubstanceorsubstancesinsidetheproductcupinthedatatable(“Aftercombining”section).Table1:_________________________________________Beforecombining AftercombiningSubstance1dissolvedinwatercalciumchloride(CaCl2):

Substance2dissolvedinwatersodiumcarbonate(Na2CO3):

Product:

Mass:

Mass:

Mass:

Whathappenedwhenyoucombinedthetwosubstancestogetherinthecup?

Thesubstanceschangedintodifferentsubstances.Thesubstancesdidnotchangeintodifferentsubstances.Iamnotsureifthesubstanceschangedintodifferentsubstances.

ChemicalReactionsSortingTool:Usethistooltohelpyouevaluateevidence.PlaceevidenceontheEvidenceGradientbasedonhowstrongyouthinktheevidenceisaccordingtotheEvidenceCriterion:Moredetailedobservationsprovidestrongerevidence.

https://apps.learning.amplify.com/sortingtool/#/tool/166/level/13_Evaluating_Evidence_id_2583

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MixingSubstancesintheSim1. LaunchtheChemicalReactionsSim:https://apps.learning.amplify.com/chemicalreactions/2. InLaboratoryAmode,presstheAddSubstancebuttonandchoosecalciumchloride(CaCl2).3. PresstheAddSubstancebuttonandchoosesodiumcarbonate(Na2CO3).4. PressTESTandobservewhathappens.5. PressRESULTSandexaminetheresults.6. PressREVIEWandcomparethesubstancesattheTestStartandTestEnd.

Drawthe“TestStart”and“TestEnd”atomicmodel.7. TurnonViewAtomicScaleandViewPropertiestoggles.

Howdothepropertiesofthedifferentsubstancescompare?

8. Useevidencefromthefinalreviewscreentohelpyouanswerthequestionsbelow.a. Whathappenedwhenyoucombinedthetwosubstancestogetherinthecup?

ExplainyouranswerusingevidencefromtheSim.Thesubstanceschangedintodifferentsubstances.Thesubstancesdidnotchangeintodifferentsubstances.Iamnotsureifthesubstanceschangedintodifferentsubstances.

b. Basedontheevidenceyoucollectedinthehands-onactivityandtheSim,answertheInvestigationQuestion:Cansubstanceschangeintodifferentsubstances?

-Whatevidencedidyougatherfromthehands-oninvestigationthatsupportsyourclaim?-WhatevidencedidyougatherfromtheSiminvestigationthatsupportsyourclaim?c. Thelawofconservationofmatterstatesthatalthoughmattercanchangeform,itcannotbecreatedor

destroyed.Inotherwords,thenumberofatomsinthereactants(the“ingredients”orsubstancesbeforeachemicalreaction)willequaltheatomsintheproducts(thethingsthataregivenoffafterthe“ingredients”undergoachemicalreaction).Howcanweprovethelawofconservationofmatterforourhands-onexperimentandSimmodel?Whatwouldyouexpecttohappen?

d. Comparethecombinedmassofthe2liquidsbeforeandafterthechemicalreaction.Thesumofthemassofthe2liquidsbeforemixingwas___________.Themassofthe2liquidsaftermixingthemwas___________.

e. Comparethenumberofeachtypeofatomatthe“TestStart”tothenumberofeachtypeofatomatthe“TestEnd.”Didyouuseanymoreoranylessofanatom?Areyourreactantsandproductsthesame?Describehowthearrangementsofatomshavechanged.

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SyntheticMaterials:MakingSubstancesintheLab

LT:Icanusetextevidencetodescribehowandwhysyntheticsubstancesaremade.

Forbillionsofyears,everysubstanceonEarthwasproducedinnature,throughnaturalprocesses,andwithoutinputfrompeople.However,withinthelastfewcenturies,peoplehavebegunexperimentingwithmakingsubstanceswecan’tfindinnature.Substancesthatareproducedbyhumansinsteadofbeingfoundinnaturearecalledsynthetic.Scientistsmakesyntheticsubstancesbyarrangingatomsandmoleculesinthelab.Theyusewhattheyknowaboutdifferenttypesofatomsandmoleculestoarrangethemandmakethekindsofsubstancestheywant.Onetypeofsyntheticmaterialthatyouprobablyuseeverydayisplastic.Scientistsdevelopedplasticsintheearly1900s.Plasticismadefrompetroleum,anaturalresourcethatisalsousedtomakegasolineandotherproducts.Bycombiningdifferentatomsandmolecules,scientistsareabletomakelotsofdifferentkindsofplasticforlotsofdifferentpurposes,frombottlestoboats.Plasticisveryuseful,butalsocausesproblems.Forexample,alargeamountofplasticendsupintheoceanandharmsoceananimals.

Insomecases,syntheticsubstancesarecopiesofsubstancesfoundinnature.Ifthesyntheticsubstancesarecopiesofnaturalsubstances,scientistscananalyzethenaturalsubstancesandarrangethesametypesofatomsinthesameway.Forexample,manyplantsfoundintherainforestsofAsia,Africa,andSouthAmericahavepropertiesthatcanbeusedforhealingallkindsofhealthproblems,fromsmallcutstoseriousdiseases.Theseplantshavebeenusedforhealingbypeoplewholiveinandneartherainforestsforthousandsofyears,andinrecentyears,scientistshavebeguntounderstandthesubstancesinsidethemthatmakethemgoodforhealing.Insomecases,scientistshavebeenabletomakesyntheticversionsofthosesubstances,producingtheminlargeamountswithoutneedingtotraveltotherainforests.

Syntheticmedicinesaren’tanydifferentattheatomiclevelfromthenaturalmedicinesfoundintherainforest.Afterall,moleculesarejustmolecules—whetherthey’remadeinnatureorinalab,thesametypesofatomsarrangedinthesamewaysalwaysformthesamemoleculesthatbehaveinthesameways.

Therainforestisarichsourceofmedicinesforhumanstouse,butitmaynotbeformuchlonger.Earth’srainforestsarebeingburnedandcutdowntomakeroomforfarmsandotheruses.Infact,about325squarekilometers(125squaremiles)arecutdowneveryday.Atthisrate,ourrainforestsmaybegonesoon.

a. Howaresyntheticsubstancesmade?b. Attheatomiclevel,aresyntheticmedicinesdifferentfromnaturalmedicines?Explainyouranswer.c. Whyisitusefultobeabletoproducesyntheticmedicines?

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Enrichment:FindingChemicalReactionsLT:Icanuseadigitalsimulationtofindtwosubstancesthatreactwhenmixedtogetherandtwosubstancesthatdonotreactwhenmixedtogether.1. LaunchtheSimandopenLaboratoryAmode:https://apps.learning.amplify.com/chemicalreactions/

2. PresstheAddSubstancebuttonandselecttwosubstancesofyourchoice.3. PressTEST,thenpressRESULTS,thenpressREVIEW.4. Withyourpartner,discusswhetherornotachemicalreactionoccurred.5. Carefullyre-watchtheatomic-scaleanimation.

a. Ifachemicalreactionoccurred,answer:Whenachemicalreactionoccurs,whathappenstotheatomsofthetwosubstances?

b. Ifachemicalreactiondidnotoccur,answer:

Whenachemicalreactiondoesnotoccur,whathappenstotheatomsofthetwosubstances?

6. Repeattheabovestepswithdifferentsubstancesuntilyouhavefoundtwosubstancesthatreactand

twothatdonotreact.7. Whenyouhavefinishedyourtests,answer:

Didanyoftheatomseverchangetype?