Presentation on theme: "Bellwork: Monday 4/23/2012 Classify the following as either a chemical change or a physical change: Boiling Burning On a molecular level, how would you."— Presentation transcript:
1Bellwork: Monday 4/23/2012Classify the following as either a chemical change or a physical change:BoilingBurningOn a molecular level, how would you describe the difference between boiling something, and burning something?Different Phase- Still same bonds; farther apart, moving fasterPhysical ChangeChemical ChangeWednesday 4/14/2010- Burning is aChemical changePhysical changeWednesday 4/14/2010- Boiling is aWednesday 4/14/2010- On a molecular level, when the atoms are still bonded the same, but the molecules are organized differently, this is aWednesday 4/14/2010- On a molecular level, when the bonds between the atoms have been broken and reformed to create a new substance, this is aNEW substance- Bonds broken, reformed
2Think about it…A garden salad is made up of lettuce, tomatoes, cucumbers, ham, egg, bacon bits, and croutons.Compare this to dissolving sugar into un-sweet tea.Hint: think about each of them as different things being mixed together—what is the end result??The salad is not a uniform mixture (one bite is different from the next) – the salad is a heterogeneous mixtureThe tea is a uniform mixture – once dissolved, the sugar is spread out evenly in the tea so one sip tastes like another – the tea is a homogeneous mixture
3Packet 12, Page 1- Mixtures & Solutions Compound- two or more substances chemically combinedOnly separated by chemical means/reactionsExamples of compounds:Salt (NaCl) – Sodium & chlorine combined chemicallyWater (H2O) – Hydrogen & oxygen combined chemicallyCarbon Dioxide (CO2) – Carbon & oxygen combined chemicallyMixture- two or more substances mixed together; NOT chemically combinedSeparated by physical meansExamples of mixtures:Bowl of cereal – mixture of cereal and milkTrail mix- mixture of various nuts, fruit, candy
4Take a Guess! Mixture or Compound? Air – mixture of gasesSoda pop – mixture of soda syrup, water, and CO2 gasFog – mixture of water and airTable salt – compound of Sodium and Chlorine: NaClKool-Aid – mixture of water, sugar, and flavor crystalsWater – compound of Hydrogen and Oxygen: H2OSalt water – mixture of salt and waterCarbon monoxide – compound of Carbon and Oxygen: CO
5“Uniform” means the same throughout 6.19- TSW USE EVIDENCE TO COMPARE AND CONTRAST HOMOGENEOUS AND HETEROGENEOUS MIXTURES.Heterogeneous mixture- a mixture in which the properties are not uniform (ex. beef stew, garden salad)“Uniform” means the same throughoutSuspension- *solid is not dissolved* Very fine particles of solid mixed with a liquid; often looks cloudy; eventually solid settles to the bottomSediment- *solid is not dissolved and settles to the bottom*
6Solute- is dissolved (s, l, g) Homogeneous mixture- a mixture in which the properties are uniform (ex. sweetened tea)Solution- *solid is dissolved* mixture in which one substance is dissolved in another; has two parts:Solute- is dissolved (s, l, g)Solvent- does the dissolving (s, l, g—usually liquid)*The solute is present in a smaller amount than the solvent*
7Solubility- How well a solute will dissolve in a solvent Insoluble- does not dissolve in waterSoluble- does dissolve in water
86.21- TSW IDENTIFY THE SOLUTE AND SOLVENT IN A SOLUTION. LemonadeSoda popOcean waterSugar (s) and Lemon Juice (l); Lemonade powder (s)Water (l)CO2 – (g) carbonation/bubblesWater (l) & Syrup (l)Salt (s)Water (l)(s) Means it is a SOLID; (l) LIQUID; (g) GAS
9Matter: Pure Substances vs. Mixtures Packet 12, Page 2 Solid, liquid, gasPure SubstanceConstant Composition; Can write chemical formula, homogeneousElementOne type of atomCompoundTwo or more different types of atoms chemically bondedMixtureVariable CompositionHomogeneoussolutionsHeterogeneousColloids and suspensions
10In-Class Work: Page 2- Classify Substance vs. Mixture Type of MatterSubstance- Element or Compound?Mixture- Heterogeneous or Homogeneous?ChlorineWaterSoilSugar waterOxygenCarbon dioxideRocky road ice creamPure airSilverEthyl alcohol (C2H5OH)AluminumTable salt (NaCl)SugarSeawaterChocolate chip cookie doughVanilla ice creamElementCompoundHeterogeneous HomogeneousElementCompoundHeterogeneous HomogeneousElementCompoundElementCompoundCompoundHomogeneousHeterogeneous Homogeneous
11Page 5- Separating Mixtures Using Physical Methods: 6 Page 5- Separating Mixtures Using Physical Methods: TSW SEPARATE MIXTURES USING THE FOLLOWING PHYSICAL MEANS: FILTERING, MAGNETISM, DISSOLVING, AND EVAPORATION.Filtration- separates a solid (or suspension) from a liquidExample: separate dirt from some salty waterHow it works: The liquid (and anything dissolved in the liquid) passes through holes in the filter paper. The solid particles are too big and get stuck.Magnetism- separates objects with magnetic properties, from non-magnetic objectsExample: separate iron from sandHow it works: The magnet sticks to the iron, not the sand.
12Dissolving- causes solid matter to pass into a liquid solution; “disappears” Example: the dissolving of salt in waterHow it works: Soluble solids will dissolve, while insoluble solids will notEvaporation- separates a dissolved SOLUTE from a SOLUTIONExample: obtain some pure salt from salty waterHow it works: When salty water is warmed the water evaporates leaving behind crystals of salt.
13Paper Chromatography- separates the different colors in dyes Example: separate the different colored dyes in ink pensHow it works: Place a dot of the dye to separate, on chromatography paper, and then dip it into a solvent. As the solvent soaks up through the paper it carries the dye with it. The more soluble dyes move further up than the less soluble ones, hence separating from each other.
14In-Class Work: Page 4 Circle/write correct answers Whatever is not finished is homework!
15Bellwork: Tuesday 4/24/2012Choose one of the five separation techniques we have studied so far and describe how they can be used to separate a mixture, and what they separate.Evaporation – how / whatMagnetism – how / whatFiltration – how / whatDissolving – how / whatChromatography – how / whatThe process that separates substances in a heterogeneous mixture through the use of a screen, coffee filter, mesh, etc., is called ________________.EvaporationMagnetismFiltrationChromatographySalt flats in Nevada’s deserts are remnants of an ancient sea. What process separated the salt from the ancient ocean?
16Separating Mixtures Lab- Page 5 Objective: Students will design, conduct, and justify an experimental design in which they combine sand, iron filings, gravel, and salt, and then use physical means to separate the mixture.Data TableProceduresConclusion QuestionsWe will be working on this lab for one day. Your mixture should be completely separated by the end of today.
17Separating Mixtures Lab Procedures - Page 5 Part 1 Procedure:Measure and record the “original mass” of the sand, iron fillings, gravel, and salt in the data table on pg. 6.Combine the sand, iron fillings, gravel, and salt in a beaker; stir until the substances are a complete jumble!Challenge:Along with your partners, you must now find a way to separate the jumble that you have created in your beaker back into the original substances: sand, iron fillings, gravel, and salt.You may only use the tools you have been given!Use Part 2 Procedure on pg. 6 to complete the challenge!We don’t have a hot plate or blow dryer so MEASURE THE MASS OF WATER IF YOU USE IT!!
18Separating Mixtures Review Filtration- separate a solid or suspension from a liquidseparating SAND from waterMagnetism- separate magnetic objects from non-magnetic objectsseparating iron from saltDissolving- causes solid matter to pass into a liquid solution; “disappears”Evaporation- used to obtain the solute from a solutionobtaining SALT from salty waterChromatography- used to separate out one color from a mixture of colorsseparating out the colors in black ink
19Answer the following questions on your bellwork. Bellwork: Thursday 4/26/12Answer the following questions on your bellwork.In the lab we did yesterday, what separation techniques worked for you and which ones did not?Write the order of separation that you found to be the best.
20 1. Filter the large gravel from the sand, salt, iron mixture. 2. Add water to the salt and sand mixture.3. Shake well until the salt dissolves. The sand does not dissolve.4. Filtration: Use the filter paper and the funnel to filter into the beaker. The salt solution passes through the paper. The sand remains behind on the paper.5. Evaporation: Put the salt solution in the evaporating basin and heat with the Bunsen burner. The water is evaporated. White salt crystals will be left behind.6. You can dry the sand by carefully heating the wet filter paper.7. You should now be left with separate piles of salt and sand!!