Presentation on theme: "Activity 20 Analysis Questions"— Presentation transcript:
1 Activity 20 Analysis Questions Analyze each of the models you built.Models of PolymersType of polymer modelStrengthsWeaknessesPaper clips linked togetherClassmates holding handsClass molecular model (Activity 19)Fits on a desktop.Can be used by one person.Clearly shows the dif. between a monomer as one paper clip and a polymer as a chain of the same unit.Does not show structure of the monomers.Takes a lot of people to use.Doesn’t show the structure of the monomers.Shows how cross-linking makes it harder to move the polymer around.It is difficult to build and work with a polymer with five or more subunits.The bonds are very rigid.You cannot use these models to test how easily a polymer can be poured or stirred.Shows atomic level.Shows the bonding within each monomer and between the monomer molecules (for example, shows the double bond in the monomer).
2 Compare the models you built in this activity. Which was most helpful when you analyzed the physical properties of a polymer?Paper clips handled easilyBoth reflected change in physical properties of the material as the polymers were cross-linkedWhich gave you a better image of the process?Most helpful when analyzing chemical reactions?Different colored paper-clips made it easy to see polymerization and cross-linkingStudent model showed the double bond in the vinyl alcohol and the need to break it to form a polymer.
3 many monomers linked together with chemical bonds = polymer Using examples from this and Activity 19, explain the relationships between a monomer, a polymer, and a cross-linked polymer. Include a sketch.a monomer is a molecule.many monomers linked together with chemical bonds = polymerchemically link polymers together = cross-linked polymerCross-linked polymerMonomerPolymer
4 How does cross-linking affect the properties of a polymer? becomes harder, thicker, more difficult to pourBased on observations, what advantages do you think polymers have on monomers?monomers are individual unitsmeans they move around easilyaren’t held together in any waypolymers are connected unitsmeans they are flexible and bendalso have strength of molecules joined togetherbeing polymers, may give plastics their strength and flexibility.
6 What are the properties of polyvinyl alcohol and sodium borate, as well as the physical properties of the product that resulted when you combined them (Activity 19)?Viscosities are very differentViscosities of the models were different(viscosity: resistance of a liquid to sheer forces (and therefore to flow)
7 What does the prefix “poly-” in polyvinyl alcohol indicate? It is a polymerIt is made up of many repeating monomers of moleculesWhat was the purpose of the sodium borate?The sodium borate provided the links to form a cross-linked polymer.
8 Was this a physical or a chemical change? The thickness of the substance changedThe color of the final product is cloudyThese are two physical changes that indicate a chemical reaction occurred.Both physical and chemical change took place.
10 Look at Activity 12Transparency 12.1, “Graphing Data About Aluminum, Plastic, and Glass.”Aluminum: easy and inexpensive to recycleGlass: more difficult and more expensiveChemical properties made the process for breaking down each container type different.Cross-Linked polymers are very difficult if not impossible to break down, making recycling difficult.
11 Doing Activity 21 Read as a group pages B-47 to B-49 Each person take turns reading a paragraph out loudTechnical reading can be difficult, help each other with the pronunciation of chemical namesFill in “Three-Level Reading Guide: Polymer Parts” togetherMake sure to discuss your choices
12 Three-Level Read Guide: Polymer Parts Check the statements below that you agree with and be ready to support your choices with ideas from the reading and from your own knowledge.cross out the words “be ready to”For parts a and b, explain whether you agree or disagree and support your choices as mentioned above.