Unit B Vocabulary. Word Definition Sentence. 12 Trade-off. 15 Atom. 15 Atomic Mass. 15 Element. Family of Elements. Periodic Table of Elements

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1 Unit B Vocabulary Word Definition Sentence 12 Trade-off 15 Atom 15 Atomic Mass 15 Element 15 Family of Elements 15 Periodic Table of Elements 16 Chemical Formula

2 Unit B Vocabulary 16 Compound 16 Molecule Periodic Table Metal Periodic Table Non-metal Periodic Table Semi-metal Periodic Table Noble Gas Atoms Atomic Number

3 Unit B Vocabulary Atoms Isotope Atoms Electron Atoms Proton Atoms Neutron 19 Chemical Reaction 19 Monomer 19 Polymer

4 Unit B Vocabulary 19 Product of Chemical Reaction 19 Reactant 20 Cross-link

5 Activity 12 Title: Evaluating Materials Problem: Which is the best material for making a drink container? Hypothesis/Initial Thoughts: Procedure: Read and follow the procedure on B-5 to B-6. Data/Observations: Table 1: Comparing Materials Advantages Disadvantages Aluminum Glass Plastic

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7 Results: Activity 12 0 Aluminum Glass Plastic Material Analysis: 1. What two types of information do you think are the most important in deciding which material to use to make drink containers? Explain. 3. Based on your information in your data table, which material is the best for making a drink container, from the viewpoint of each person listed below? Explain your answer for each of these people and support it with evidence from the activity. a. a consumer concerned with cost and convenience b. an environmentalist concerned with energy usage, litter, and problems with a bottle s impact on the environment c. a recycling-center owner who must handle all of the containers turned in for recycling 5. What do you think is the best material to use to make drink containers? Support your answer with evidence and identify the trade-offs of your decision.

8 Activity 14 Title: Physical and Chemical Properties of Materials Problem: How do the properties of material determine their uses? Hypothesis/Initial Thoughts: Procedure: Read and follow the procedure on B-15 to B-17. Background: Properties Definition Physical Can be determined without seeking a chemical reaction. It is a quality or trait that describes a material or object. Chemical Can only be determined by adding another chemical to see if a reaction occurs Examples of Properties Change Definition A physical change occurs when a substance changes its state (solid, liquid, gas) or when it is broken into smaller pieces or combined into larger ones. A change in how atoms or molecules are bonded to each other, resulting in a new arrangement of atoms or molecules. A chemical change always results in changed physical properties Examples of Change Data/Observation: See Testing Physical and Chemical Properties and Categories of Materials

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10 Results: Categories of Materials Category Ceramics Metals Plastics Natural Common Properties Hard, brittle materials that are formed by heat. Usually shiny solids that conduct heat or electricity and can usually be formed into sheets and drawn into wires. Chemical compounds usually made from petroleum products. Plastics can be molded into various shapes Materials that are found in nature. Examples Analysis: 2. Should the shape of an object be considered a property of the material? Explain. 4. For each product listed in the first column, complete the table by listing one material you tested that would work well and one that would not work well. Explain your reasons for each. Table 2: Selecting Materials for Products Use of material Materials that would Reason work well Electrical wire Materials that would NOT work well Reasons Garden statue Toy boat Tabletop Inexpensive container for an acid, such as vinegar

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12 Activity 15 Title: Families of Elements Problem: How can elements be grouped based on their physical and chemical properties? Hypothesis/Initial Thoughts: Procedure: Read and follow the procedure on B-20 to B-21. Background: Element symbol Element name Physical characteristics Chemical characteristics H Hydrogen non-metal gas colorless Atomic mass: 1 Reactivity: high Number of bonds to hydrogen: 1 Data/Observation: My classification system Procedure #4 Group Name: Common Properties

13 New classification system Activity 15 Procedure #9 Family Name Similar Properties Elements in order of increasing atomic mass Analysis: 1. Which of the properties listed on the Element Cards are: a. physical properties? b. chemical properties? 4. Use the table of elements you constructed to find the family or families of elements that are: a. not usually reactive. b. highly reactive. c. all metals. d. all solids. e. all gases. 5. The element strontium (Sr) is below calcium (Ca) in Column 2 on the periodic table. Design an Element Card that shows the properties you predict for strontium.

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16 Periodic Table Notes- Metal, Nonmetals and Semimetals Characteristic Properties Metals (located to the left of the zig-zag line) of electricity and heat density melting temperature Reactive Usually Usually (bright, shiny, glossy, etc.) In chemical reactions, metals lose electrons to form positively charged ions Most known elements are All are at room temperature except for, which is a liquid at room temperature and pressure Nonmetals (located to the right of the zig-zag line) conductors of heat and electricity density melting temperature lustrous ductile or malleable Can be Solid nonmetals are Tend to gain electrons in reactions with metals to form negatively charged ions Share electrons in reactions with other nonmetals Good Semimetals (Metaloids) (touch the zig-zag line) Can exhibit properties of Can bond with many different elements reactive Have a varying ability to conduct electric current ( ). Used in chips

17 Periodic Table Notes- Families (Groups) Families Elements in the same vertical column ( ) are called or groups. Elements in the same family have similar Atomic mass as you move down the columns Periods Horizontal rows are called Atomic mass from left to right in the periods Elements in the same period Alkali Metals (Group 1) Characteristic Properties Hydrogen is, it is a nonmetal electron in the outer shell Soft and silvery metals, especially with water electricity Alkaline Earth Metals (Group 2) electrons in the outer shell White and malleable, but less than Alkali Metals electricity Halogens (Group 7) electrons in the outer shell Almost all are, are often bonded with elements from group 1 Noble Gases (Group 8) Exist as electrons in the outer shell = He ( ) has only electrons in the outer shell = (or rarely) with other elements

18 Activity 16 Title: Elements and the Periodic Table Problem: What are elements, and how do they relate to compounds? Hypothesis/Initial Thoughts: Data/Evidence: Stopping to Think 1: In what way were the ancient Greek philosophers right about elements? In what way were the ancient Greek philosophers wrong? Stopping to Think 2: How did Mendeleev build on other scientists work? How did other scientists build on Mendeleev s work?

19 Stopping to Think 3: Use the Periodic Table of the Elements on B-27 to decide whether each of the following is a metal or nonmetal: Element Metal or Nonmetal Element Metal or Nonmetal lithium (Li) calcium (Ca) carbon titanium (C) sulfur (S) (Ti) bromine (Br) Stopping to Think 4: Find magnesium on the periodic table. What is magnesium s chemical symbol? What family does magnesium belong to? Is magnesium a solid, a liquid, or a gas? Based on its family, would you expect magnesium to be very reactive, somewhat reactive, or not reactive at all? Stopping to Think 5: What are two ways that compounds are different from the elements that form them? Stopping to Think 6: The chemical formula for baking soda is NaHCO3. What elements are in baking soda? How many of each type of atom is represented by the formula for baking soda?

20 Analysis: Activity Use the Periodic Table of Elements to find out which atoms make up a molecule for each of the substances listed. The first row has been completed for you. Water Substance Chemical Formulas of Common Substances Chemical Atoms that Make up the Molecule Formula H 2 O Hydrogen Peroxide H 2 O 2 Carbon Dioxide CO 2 Sucrose (Table C 12 H 22 O 11 Sugar) Alanine (an amino C 3 H 7 O 2 N acid) Oleic Acid (a fat) C 12 H 24 O 2 2. Sodium is a metallic solid, and chlorine is a poisonous yellow-green gas. Sodium and chlorine react to form sodium chloride, which is common table salt. a. Is table salt an element or a compound? Explain. b. Describe the physical properties of table salt. c. How do the properties of table salt compare with those of sodium and chlorine? 3. Is seawater an element, compound, or mixture? Explain your answer. 4. Explain the relationship between an atom and a molecule.

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22 Periodic Table of Elements Reading Guide Name: Main Point (p. xxix): The organization of the is based on the of the and reflects the structure of. Part I: p Label each part of this square, which is found in the periodic table of elements: 26 Fe Iron = # of in an atom s nucleus is the average of an element s atoms Isotopes are (p. 130) (Page xxix) Each element has a specific number of in the (the ) and each of the element has a different but specific number of in the nucleus. Part II: Define the following terms: 1. Metals (p.138): 2. Nonmetals (p.149): List the symbols of the 11 nonmetals:,,,,,,,,,, 3. Semi-metals (p.155): List the 8 semimetals:,,,,,,, 4. Noble Gases (p.154): List the 6 Noble Gases:,,,,,

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24 Name Date Period Element Compound Mixture Diagram Description Example Same: Different:

25 Lego Atomic Structure Draw each set of Legos. Under description write down each of the following that applies: A B Description Only one color not connected Only one color Science Description C At least two Legos connected D At least two different colors connected Sample Sketch (include color) Description Science Description Mixture? Yes or No Similarities & Differences 1 2 3

26 Sample Sketch (include color) Description Science Description Mixture? Yes or No Similarities & Differences

27 Name Date Period Elements, Compounds & Mixtures Worksheet Part 1: Read the following information on elements, compounds and mixtures. Fill in the blanks where necessary. Elements: A pure substance containing only one kind of. An element is always uniform all the way through (homogeneous). An element be separated into simpler materials (except during nuclear reactions). Over 100 existing elements are listed and classified on the. Compounds: A pure substance containing two or more kinds of. The atoms are combined in some way. Often times (but not always) they come together to form groups of atoms called molecules. A compound is always homogeneous (uniform). Compounds be separated by physical means. Separating a compound requires a chemical reaction. The properties of a compound are usually different than the properties of the elements it contains. Mixtures: Two or more or NOT chemically combined. No reaction between substances. Mixtures can be uniform (called ) and are known as solutions. Mixtures can also be non-uniform (called ). Mixtures can be separated into their components by chemical or physical means. The properties of a mixture are similar to the properties of its components. Part 2: Classify each of the following as elements (E), compounds (C) or Mixtures (M). Write the letter X if it is none of these. Diamond (C) Sugar (C6H12O6) Milk Iron (Fe) Air Sulfuric Acid (H2SO4) Gasoline Electricity Krypton (K) Bismuth (Bi) Uranium (U) Popcorn Water (H2O) Alcohol (CH3OH) Pail of Garbage A dog Ammonia (NH3) Salt (NaCl) Energy Gold (Au) Wood Bronze Ink Pizza Dry Ice (CO2) Baking Soda (NaHCO3) Titanium (Ti) Concrete

28 Part 3: Match each diagram with its correct description. Diagrams will be used once. A B C D E 1. Pure Element only one type of atom present. 2. Mixture of two elements two types of uncombined atoms present. 3. Pure compound only one type of compound present. 4. Mixture of two compounds two types of compounds present. 5. Mixture of a compound and an element. Part 4: Column A lists a substance. In Column B, list whether the substance is an element (E), a compound (C), a Heterogeneous Mixture (HM), or a Solution (S). (Remember a solution is a homogeneous mixture.) In Column C, list TWO physical properties of the substance. Column A Column B Column C 1. Summer Sausage 2. Steam 3. Salt Water 4. Pencil lead (Pb) 5. Dirt 6. Pepsi 7. Silver (Ag) 8. Toothpaste (Na2HPO4) 9. A burrito 10. Italian Dressing 11. Chicken Soup 12. Lemonade

29 Graphic Organizer: Substances

30 Bill Nye: Atoms! 1. is all of the stuff around you. 2. Atoms come from the Greek word that means. 3. are tiny and filled with empty space they are the building blocks of matter. 4. Atoms are too to see, even with a. 5. What is the purpose of the Cheese analogy? 6. The is found in the middle of an Atom. 7. Inside the nucleus, there are and. 8. Protons have a electrical charge and the neutrons have. 9. Buzzing around the outside of the nucleus are VERY small particles called. 10. Everything is made of. Atoms are mostly empty! 11. Atoms are so small, that you could put on the head of a pin. 12. Atoms are the basic. 13. All matter is made of and. 14. Atoms combine to make. 15. Water is made of 2 parts Hydrogen and 1 part. 16. What is the purpose of the Nifty Home Experiment that was shown on the video? 17. What makes one atom different from another? The number of in the. 18. What is the atomic number of an atom? The number of in the. 19. There are elements that occur naturally. You can combine them to make different. 20. Carbon is important because carbon is! Carbon is the to life!

31 Elements of the Periodic Table Atomic Number Chemical Symbol Chemical Name Hydrogen Atomic Weight The average weight of all naturally occurring isotopes of the element Atomic # = Atomic mass = (Mass number) (round the atomic weight to the nearest whole #) It is also known as the mass number. The Atom Mass = (Number of Protons) + (Number of Neutrons) # of Protons = (the atomic number = the number of protons) # of Neutrons = (atomic mass - atomic number) # of Electrons = (By definition, atoms have no overall electrical charge. Atoms must have equal numbers of protons and electrons.) # electrons = # protons = atomic number Fill in the blanks for each element Silicon B Atomic # = Atomic mass = # of Protons = # of Neutrons = # of Electrons = Atomic # = Atomic mass = # of Protons = # of Neutrons = # of Electrons = Atomic # = Atomic mass = # of Protons = # of Neutrons = # of Electrons =

32 16 S Iodine Mn Atomic # = Atomic mass = # of Protons = # of Neutrons = # of Electrons = Atomic # = Atomic mass = # of Protons = # of Neutrons = # of Electrons = Atomic # = Atomic mass = # of Protons = # of Neutrons = # of Electrons = 12 Mg Argon K Atomic # = Atomic mass = # of Protons = # of Neutrons = # of Electrons = Atomic # = Atomic mass = # of Protons = # of Neutrons = # of Electrons = Atomic # = Atomic mass = # of Protons = # of Neutrons = # of Electrons = 79 Gold H Flourine Atomic # = Atomic mass = # of Protons = # of Neutrons = # of Electrons = Atomic # = Atomic mass = # of Protons = # of Neutrons = # of Electrons = Atomic # = Atomic mass = # of Protons = # of Neutrons = # of Electrons =

33 Title: States of Matter States of Matter Problem: How do solids, liquids, and gases differ in the motion of their particles? Hypothesis/Initial Thoughts: Procedure: Take notes and fill in the solid, liquid and gas table from the power point Data/Observation: STATES OF MATTER Based on A compound or element can, but can still be. Temperature or pressure changes Energy (heat) added energy (temperature) taken away. Phase Changes

34 Data/Observation (cont.): Property Comparison of Gas, Liquid and Solid Property Gas Liquid Solid Shape Volume Movement of particles Arrangement of particles Picture Analysis: 1. How can the motion of particles in a solid be described? 2. What happens to the particles of a solid as it becomes a liquid? 3. What determines the shape and volume of a gas inside a container?

35 Solid, Liquid and Gas Computer Lab Use the links on today s date on my science calendar. Fill in the blanks using the information on Site A. How are the pictures of solids, liquids, and gasses different from each other? List 3 ways List one way in which all three pictures are similar. 1. Some Characteristics of Gases, Liquids and Solids and the Microscopic Explanation for the Behavior Gas Liquid Solid assumes the of its container particles can one another assumes the of the part of the which it occupies particles can past one another retains a fixed and shape rigid - particles lots of between particles not easily little free space not easily little free space between flows can move past one another flows particles can move/slide does not easily rigid - particles cannot or past one another

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37 Use Site B to answer the following questions. Write complete sentences using words from the question in your answer: 1. What happens to the particles of a solid when you cool them off? 2. Why can you pour a liquid? From the Revise section fill in the blanks: Solids, liquids and gases when heated and when cooled Particles do not change, only the Solids have a but gases and liquids can Read the rest of the Revise section. Take the Test on solids, liquids, gases. Use Site C to review Compounds and Mixtures When you heat iron and sulfur you create bonds. The bonds fuse the atoms together. Can you separate them? At room temperature, how are the properties of oxygen and hydrogen different from the properties of water? What are three methods to separate mixtures? THINK--- Why wouldn t these methods work for separating elements in a compound? (This isn t in the video--- use your brain!) From the Revise section What is a compound? Read the rest of the Revise section. Take the Test.

38 Activity 17 Title: Modeling Molecules Problem: How do atoms combine to form molecules? Hypothesis/Initial Thoughts: Procedure: Read and follow the procedure on B-32 to B-33. Data/Observation: Part A: Procedure steps 2 and 3 Procedure Step 6 Procedure Step 5 Procedure Step 7 Part B: Procedure Step 11

39 Procedure Step 12 Procedure Step 15 Analysis: 3. Was it possible for an atom to make more than one bond? Explain and give an example. 4. How many bonds could each of the following make with hydrogen? Use the atomic numbers to help you find the element on the periodic table. Answer using the table below. Bonds with Hydrogen Element Atomic number Number of bonds with hydrogen Si 14 S 34 I 53 As If you had two oxygen atoms and one hydrogen atom, could you form a molecule? Explain. 6. Make a drawing to show the difference between an atom and a molecule.

40 Matter Reading Guide Name: Main Point (p.xxv): Each of the more than 100 of has distinct and a distinct. All forms of matter are composed of one or more of the. Part I: Word Bank Atoms Mass Matter Space Matter is anything that has and takes up. All is made up of. (p. 58) Part II: Fill in the following table with these examples: Ashes Rock Water Pottery Gas Rainbow Heat Light Ideas Thought Matter Not Matter Part III: (Look at Figure 7 on p. 128 for help)

41 Proton Particles of an Atom (p. 128 Figure 7) Particles Electric Charge Location in an Atom Electron Neutron Part IV: Word Bank: atoms electrons electron cloud neutron nucleus proton Matter is made up of containing particles with Part VI: (p.xxv) The structure of the atom is composed of,, and. Compounds are formed by combining two or more different. Compounds have that are different than the elements that make them. a positive charge a neutral charge a negative charge These are found in the These are found in the Part V: p Substances: Mixtures Elements Compounds Examples: Copper (Cu) Salt (NaCl) Silver (Ag) Air (O2+N2+CO2) Sea Water (water, salt, oxygen) Sugar (C12H22O11) Description Substance Matter that has the same composition and properties throughout A substance made up of more than one element, bonded together to make a new substance Two or more substances that come together but do not make a new substance 2 Examples

42 BUILD AN ATOM PART I: ATOM SCREEN Build an Atom simulation ( 1. Explore the Build an Atom simulation with your group. As you explore, talk about what you find. 2. a) List two things your group observed in the simulation. b) What particle(s) are found in the center of the atom? 3. Play until you discover which particle(s) determine(s) the name of the element you build. What did you discover? 4. What is the name of the following atoms? a) An atom with 3 protons and 4 neutrons: b) An atom with 2 protons and 4 neutrons: c) An atom with 4 protons and 4 neutrons: 5. Play with the simulation to discover which particles affect the charge of an atom or ion. a) Fill in the blanks below to show your results: Neutral atoms have the same number of protons and electrons. Positive ions have protons than electrons. Negative ions have protons than electrons. b) Develop a relationship (in the form of a single sentence or equation) that can predict the charge based on the number and types of particle. 6. Play with the simulation to discover what affects the mass number of your atom or ion. a) What is a rule for determining the mass number of an atom or ion? 7. Practice applying your understanding by playing 1 st and 2 nd levels on the game screen.

43 PART II: SYMBOL SCREEN 8. Using the Symbol readout box, figure out which particles affect each component of the atomic symbol. a) In the atomic symbol below, label each letter (a, b, c, and d) with: the particle(s) used to determine the letter, and how the value of each letter is determined. 9. Create a definition (using a complete sentence) for each of these items based on your labels from the atomic symbol above. a) Element Symbol b) Charge c) Atomic Number d) Mass Number d a b c 10. Practice applying your understanding by playing the 3 rd and 4 th game levels. Play until you can get all the questions correct on the 4 th level. 11. In addition to atomic symbol, we can represent atoms by name and mass number. a) Complete the table below: Symbol 12 6C F 11 5 B Name Carbon-12 b) Each representation (Symbol and Name) in the table above provides information about the atom. Describe the similarities and differences between the Symbol and Name representations.

44 PART III: ISOTOPES 12. Play with the simulation to determine: a) Which particles affect the stability of the atom? b) Which particles do not affect the stability of the atom? 13. What are the names of the stable forms of oxygen? a) Oxygen-16 b) Oxygen- c) Oxygen- d) List all of the things that are the same about these atoms (ignore the electrons). e) List all of the things that are different about these atoms (ignore the electrons). 14. The atoms in the previous question are isotopes of each other. Based on this information, list the requirements for two atoms to be isotopes of each other. 15. Test your understanding of isotopes by examining the relationships between the pairs of atoms listed below: Atom 1 Atom 2 Relationship between atom 1 and atom 2 12 Isotopes Same Atom, Not Isotopes of Each Other 6C 13 6C Different Element Carbon-12 Argon B An atom with 13 protons and 13 neutrons 12 6C Argon-41 Boron-10 An atom with 14 protons and 13 neutrons Isotopes Same Atom, Not Isotopes of Each Other Different Element Isotopes Same Atom, Not Isotopes of Each Other Different Element Isotopes Same Atom, Not Isotopes of Each Other Different Element Isotopes Same Atom, Not Isotopes of Each Other Different Element

45 EXERCISES 16. The periodic table has a great deal of information about every atom. Using your periodic table, answer the following questions: a) What is the atomic number of chlorine (Cl)? b) What is the atomic number of tungsten (W)? c) How many protons are there in any Cl atom? d) How many protons are there in any Te atom? e) Can you tell from the periodic table exactly how many neutrons are in an atom? 17. Complete the following table: Atomic Mass Number of Number of Name Symbol Charge number Number neutrons Electrons hydrogen-2 2 H H sodium Na Ti Ag 19 F -1 carbon-12 6 carbon-13 6 carbon-14 6 carbon-12 7 carbon He argon Ga 70 Ga To test your knowledge of isotopes, draw arrows between all pairs of atoms in the table above that are isotopes of each other.

46 IDENTIFYING ISOTOPES Step 1 - Gather Information The first thing you will need to do is find some information Mass about your element. Use the Table of Elements to find your element's atomic number and atomic mass. The atomic number is the number located in the upper left corner and the atomic mass is the number located on the bottom, as in the example shown above for krypton. Step 2 - The Number of Protons is... The atomic number is the number of protons in an atom of an element. In our example, krypton's atomic number is 36. This tells us that an atom of krypton has 36 protons in its nucleus. The interesting thing here is that every atom of krypton contains 36 protons. If an atom doesn't have 36 protons, it can't be an atom of krypton. Adding or removing protons from the nucleus of an atom creates a different element. For example, removing one proton from an atom of krypton creates an atom of bromine. Step 3 - The Number of Electrons is... By definition, atoms have no overall electrical charge. That means that there must be a balance between the positively charged protons and the negatively charged electrons. Atoms must have equal numbers of protons and electrons. In our example, an atom of krypton must contain 36 electrons since it contains 36 protons. Step 4 - The Number of Neutrons is... The atomic mass is basically a measurement of the total number of particles in an atom's nucleus. In reality, it isn't that clean cut. The atomic mass is actually a weighted average of all of the naturally occurring isotopes of an element relative to the mass of carbon-12. All you really need to find is something called the mass number. Unfortunately, the mass number isn't listed on the Table of Elements. Happily, to find the mass number, all you need to do is round the atomic mass to the nearest whole number. In our example, krypton's mass number is 84 since its atomic mass, 83.80, rounds up to 84. The mass number is a count of the number of particles in an atom's nucleus. Remember that the nucleus is made up of protons and neutrons. So, if we want, we can write: For krypton, this equation becomes: Mass Number = (Number of Protons) + (Number of Neutrons) 84 = (Number of Protons) + (Number of Neutrons) If we only knew how many protons krypton has, we could figure out how many neutrons it has. Wait a minute... We do know how many protons krypton has! We did that back in Step 2! The atomic number (36) is the number of protons in krypton. Putting this into the equation, we get:

47 84 = 36 + (Number of Neutrons) What number added to 36 makes 84? Hopefully, you said 48. That is the number of neutrons in an atom of krypton. The interesting thing here is that adding or removing neutrons from an atom does not create a different element. Rather, it creates a heavier or lighter version of that element. These different versions are called isotopes and most elements are actually a mixture of different isotopes. If you could grab atoms of krypton and count the number of neutrons each one had, you would find that most would have 48, others would have 47, some would have 50, some others would have 46, a few would have 44 and a very few would have 42. You would count different numbers of neutrons because krypton is a mixture of six isotopes. In Summary... For any element: Number of Protons = Atomic Number Number of Electrons = Number of Protons = Atomic Number Number of Neutrons = Mass Number - Atomic Number The mass number is the atomic mass rounded to the nearest whole number!! In the examples shown below, the mass number is written next to the symbol for each element. Ex: For isotope 14 C, 14 is the mass number for this isotope of Carbon. Isotope Name 14 C 40 Ca 238 U Atomic Number Mass Number # of Protons # of Neutrons # of Electrons

48 Title: Creating New Materials Activity 19 Background: Vinyl Alcohol Vinyl Alcohol Molecule = Polyvinyl Alcohol = monomers form a polymer. Poly means Mono means Polyvinyl Alcohol Chemical Reaction (can be one product or more) Sodium and Water Demo: 2Na + 2H 2 O 2NaOH + H 2 Reactant: a substance that in a chemical reaction Product: a substance of a chemical reaction

49 Activity 19 Problem: How are reactants changed by a chemical reaction? How are the products different? Hypothesis/Initial Thoughts: Data/Observation: Comparing Properties of Polymers Polyvinyl alcohol (original polymer) Color Sodium borate New polymer How well does it pour? Can it be stirred? Stickiness Stretchiness Bounciness Additional observations Analysis: 1. How do the physical properties of the final product compare to the physical properties of: a. polyvinyl alcohol (PVA), one of the reactants? b. sodium borate, the second reactant, which you added to the PVA? 2. What evidence can you provide that a new substance formed?

50 Activity 20 Title: Modeling Polymers Problem: How can you use models to represent changes that occur during a chemical reaction? Hypothesis/Initial Thoughts: Procedure: Follow the procedure on pages B-43 to B-45 Data/Observation: Comparing Model Monomers and Polymers Monomer Polymer Cross-linked polymer Vinyl alcohol Polyvinyl alcohol (PVA) Cross-linked PVA Pouring Stirring Pulling

51 Analysis: Activity Models provide ways to represent complex systems. In Activity 19, Creating New Materials, and this activity you made a total of three models of polymers. Analyze each of the models you built. Models of Polymers Type of polymer model Strengths Weaknesses Paper clips linked together Classmates holding hands Class molecular model (Activity 19) 2. Compare the models you built in this activity. a. Which was the most helpful when you analyzed the physical properties of a polymer? b. Which was the most helpful when you analyzed the chemical reaction that occurred? 3. Using examples from this and Activity 19, Creating New Materials, explain the relationships between a monomer, a polymer, and a cross-linked polymer. Include a sketch to illustrate your explanation. 4. How does cross-linking affect the properties of a polymer?