Presentation on theme: "Chemistry The Science of Matter Pages 4-9 in the text."— Presentation transcript:
1 ChemistryThe Science of MatterPages 4-9 in the text
2 Do NowList at least 5 chemicals that you are familiar with from past experience.
3 Learning ObjectiveUnderstand composition and their impact on the properties of matterBe able to classify chemical vs. physical changes
4 ChemistryThe science that investigates the structure and properties of matterMatter: anything that takes up space and has massMass: the measure of the amount of matter that an object containsNOT Matter-HeatLightRadio waves etc.
5 Matter continuedStructure: refers to what it is made of and of how it is organizedProperties: Describe the characteristics and behavior of matter including the changes it undergoes
6 Behavior of Matter Determined by BOTH The elements it contains Arrangement of those elements
7 Example Salt vs. Water Sodium and Chloride Hydrogen and Oxygen Contain different elements --- Have different properties!
8 Example Aspirin Vs Table Sugar Both contain only Carbon, Hydrogen and Oxygen molecules --- same compositionDifferent Structures Cause Different Behaviors!
9 ExampleTwo Different Artificial Sweeteners Aspartame Saccharine Different Compositions Both have: C, H, O and N and are sweet Only Saccharine has Na+ and S Their arrangement must be a factor!
10 Identifying Properties Many are easy to observe by simple testsUse heat, magnets, electricity etcColorState: solid, liquid or gas at room temp and pressureSoft or hardDoes it burn?Does it dissolve in water?These are from a macroscopic perspectiveThings you can touch, taste, feel, smell and see
11 What is it made of? This question is harder to answer Must take measurementsMust observe chemical changesMacroscopic ObservationsSubmicroscopic perspectiveTo understand hidden structure influences behavior
12 Physical change vs. Chemical change Doesn't change what the substance is.A new substance is formed and energy is either given off or absorbed.Can be reversedCannot be reversed with the substance changed back without extraordinary means, if at all.
13 Examples Physical Change Chemical Change Paper cut into pieces, small pieces are still paperPaper burned is no longer paperDissolve sugar in waterMake a cake with flour, water, sugar and other ingredients and bake them, it would take extraordinary means to separate the various ingredients out to their original form.
14 Physical Vs. Chemical Change Worksheet (10 minutes) In pairs complete the given handoutYou may use your notesBe sure that you are prepared to share your answers with the class
15 Share Answers (3 min/group) Each table shares their answers with the class.Be sure to explain why you chose your answer.ALL STUDENTS MUST RECORD THE CORRECT ANSWER ON THEIR HANDOUT!
16 Thanks for doing your best work! Exit Ticket – Answer individually Write your name! Please number your index card 1-5List 5 different properties of matter which can be used to identify a substance.Define Chemical changeDefine physical changeList 3 examples of a chemical changeList 3 examples of a physical change.PLACE YOUR EXIT TICKET IN THE TRAY ON YOUR WAY OUT!Thanks for doing your best work!
17 Chemical properties vs. Physical properties Chemical Property• Flammability: The ability to burn• Ability to rust: Reacts with oxygen to produce rust• Reactivity with vinegar: Reacts with vinegar to produce new substancesPhysical Property• Transparency: The property of letting light pass through something• Boiling point: Temperature at which a substance goes from liquid to gas• Melting point: Temperature at which a substance goes from solid to a liquid• Brittleness: Tendency to crack or break• Ductility: Ability to bend without breaking• Elasticity: Ability to be stretched or compressed then return to original size• Density: Mass per unit volume
18 Let’s look closely at Density It is an important property of matterIt is used to identify substancesIt is also used to separate mixturesDefinition of Density: the mass of a specific unit of volumeIt is expressed in the following equation;D= m/v or density = massvolume
19 Density In solids it is usually expressed as; grams per cubic meterg/cm3Kilograms per cubic meterKg/m3In liquids it is usually expressed as;grams per literg/Lgrams per cubic centimeter
20 Example of Density Calculations If a piece of rock has a mass of 14g and a volume of 5 cm3, what is the density?Step 1: Write the given and ensure proper unitsm =14 g V= 5 cm3Step 2: Write the formulaD= m/vStep 3: Substitute the given into the formulaD = 14g / 5 cm3Step 4: solveD=2.8 g/cm3
21 Your turn to work! Alone, Silently Read the first 2 pages (4 min) Highlight or underline any concepts which we have already mentioned as important, in ppt.Circle any new informationUse a sticky note to write out any questions you have
22 Now you try some problems! Work with your partner to answer questions for practice exercise 1 and 3 (10 min)You may use a calculatorWrite out all stepsLabel all unitsBe prepared to put your answer on the board!
24 Submicroscopic Level of Matter Matter is made of AtomsAtomsSo small they can not be seen with the most powerful light microscopeSo small that if a period at the end of a sentence were made of Carbon atoms it would be made of 100 quintillion carbon atoms(100, 000,000,000,000,000,000)Counting them at 3 per second would take you a trillion years!Scanning Tunneling Microscope (STM)creates computer images which are a visible perspective showing atomic location
25 Scanning Tunneling Microscope (STM) individual iron atoms on a silver substrate
26 Using Chemical Models Show types and numbers of atoms Show arrangement of the atoms and space filled
27 Why Models? Submicroscopic structural representation Explains observed behaviorUsed to predict behavior not yet observedBuilt on investigation and experimentation
29 Classifying Matter Substance: matter with constant composition Element: Made of only one type of atomCompound: 2 or more elements that are chemically combinedMixture: Matter with variable compositionHeterogeneous Mixture: Made up of more than 1 phaseHomogeneous Mixture: also called solutions, made up of only 1 phase
30 MixturesA material that is made of 2 or more things which are not combined chemicallyEach of the parts still keep their own identitiesMade by blending, but NOT forming chemical bonds or chemical change!Most everyday matter occurs as mixtures
31 Heterogeneous and Homogeneous Mixtures A classification of matter based on compositionHomogeneous mixture: no clumping or grouping but rather a uniform dispersal of the material it is made of.Ex. Air; made of N2, O2, CO2 and other gasesA liquid in which there is a solvent and a solute is called a solutionHeterogeneous mixture: it is easy to identify all if the different components
37 Solutions (homogeneous) Air (gas)Martini (liquid)Salt water (liquid)Plastic (solid)
38 Substances Homogeneous materials that contain only 1 kind of matter Have definite composition and propertiesSubstances which can not be broken down into a simpler substance is an ELEMENT.Substances which can be broken down into a simpler substance is a COMPOUND.They are made of 2 or more elements
39 Elements Made of only one kind of atom Can not be made simplified by physical or chemical meansCan exist as atoms (carbon) or molecules (N2)
40 Compounds Consist of 2 or more DIFFERENT atoms bound together (H2O) Can be broken down into smaller types of matter by chemical means only.Have properties which are different than the elements they are made ofAlways contain the same ratio of its components atoms ( ex 2 hydrogen's to 1 oxygen, in water)
41 Classify the Following Ocean water-Calcium-Vitamin C-Dry ice –Copper-Grain alcohol-after shave lotion-Hamburger-Al foil –Milk-Salt-Iron nail-
43 Learning Objectives Investigate various ways to separate mixtures Identify the properties of the matter that allow for a particular method of separation
44 REMEMBER MixturesAre made of 2 or more things which are not combined chemicallyEach of the parts still keep their own identitiesMade by blending, but NOT forming chemical bonds or chemical change!Most everyday matter occurs as mixtures
45 Separating MixturesMixtures can be separated through a physical process, (the identity of the substance remains unchanged).Using their Physical propertiesBringing about physical changes to separate the mixture into its components (different substances it is made of)
46 REMEMBER: Physical Properties Density: Mass per unit volumeSolubility in water : Does it dissolve in water?State of mater: at room temp and pressureTransparency: lets light pass throughBoiling point: Temperature at which a substance goes from liquid to gasMelting point: Temperature at which a substance goes from solid to a liquidBrittleness: Tendency to crack or breakDuctility: Ability to bend without breakingElasticity: Ability to be stretched or compressed then return to original size
49 How can we separate it? What do you think? Work with your lab partner to come up with a suggested method. (10 minutes)You may use your class notes, but your brain is your best asset.Write your thoughts in your notebooks.Do not be afraid to try!
50 Report out on ideas So, what did you come up with? Share your thoughts! (10 minutes)
51 What can we do?Method #1Use a pair of tweezers and a microscope to physically separate the particlesRequires a lot of time and patience
52 Method #2 Step #1 Recall the properties of water and of sand Sugar dissolves in waterSand does NOTUse the difference!Method #2
53 Step #2 Recall the properties again sand will not pass through a filterSugar and water solution willUse the difference!
54 Step #3 Recall the properties of sugar and water water will ! sugar will not evaporate (change state) at 100 degrees Celsiuswater will !Use the difference!Step #4
55 You have the two pure substances again! Sand in the filter!Sugar in the bottom of the beaker!
56 Learning objectiveUnderstand the relationship between chemical change and energy change
57 Mixtures vs. Pure substances Mixtures can be separated based physical properties and through physical changePure substances can only be separated through chemical changesSeparated from compounds into elementsH2O- H and O2Made into compounds from elementsH + O H2O
58 Chemical Change and Energy All chemical changes involve some sort of energy change!Many chemical changes (reactions) release energyExothermic reactions: release energy as heatSome reactions absorb energyEndothermic reactions: absorb heat energy
59 Epsom salt and laundry detergent DemoEpsom salt and laundry detergent
60 Lab Thursday! Paper Chromatography! A method of separating mixtures based on their ability to dissolve or on the size of particles.
61 More methods of separating mixtures Paper chromatographySeparating the dyes in inkDyes are usually made of several basic colors called pigmentsUsing the property of these dyesSoluble in water we will separate the pigments
62 Develop a question! Make a claim (hypothesis) Follow the Procedure Answer the lab analysis questionsDraw a conclusionAsk a new questionCreate a poster presentation of your results
63 Be sure to study your notes and your review sheets! Unit Test on Monday!Be sure to study your notes and your review sheets!