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Objectives: Define and distinguish between monomers and polymers. Compare saturated and unsaturated hydrocarbon structures and properties. Please put your name on NOW! So you don’t forget Catalyst: So far we have learned about alkanes. Describe an alkane.
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Objectives: Define and distinguish between monomers and polymers. Compare saturated and unsaturated hydrocarbon structures and properties. Please put your name on NOW! So you don’t forget Catalyst: So far we have learned about alkanes. Describe an alkane. Describe at least 3 ways that a hydrocarbon molecule be more complex than a simple alkane. Homework: Read C.5, Do: pg. 279 #6-12
C1 Petrochemicals Chemists use hydrocarbons and knowledge of covalent bonding to build new molecules Until 1800s all materials were natural materials. Eg stone, wood, cotton, silk Commercially made products: cellulose from wood and shellac from insects. These are polymers – long chain molecules made out of monomers Modern products are more man-made. Petrochemical – man-made out of petroleum. Eg: insulation, plastic, foam, fabrics like nylon, detergent, pesticides
Ethene – builder molecule C2H4 Aka ethene Contains a very reactive double covalent bond, Addition reactions – add a reactant onto double bond Etheneand water form ethyl alcohol
Ethene can do an addition reaction with itself. Makes polyethylene – contains 500 to 20,000 ethenes linked in a chain Polyethylene is an example of an “addition polymer” Other polymers are made from monomers like ethene: vinyl chloride to Polyvinylchloride (PVC)
Polymers Polymers can be long straight chains (like spagetti), branched, or cross-linked
C.3 Beyond Alkanes • Alkane – a hydrocarbon with all single bonds • Alkene – a hydrocarbon with at least one double bond • Double covalent bond – two pairs of electrons (total of 4 electrons) are shared. • Saturated hydrocarbon – each carbon is bonded to 4 other atoms. It’s “full.” • Unsaturated hydrocarbon – not all carbon atoms are bonded to four other atoms.
Saturated v. Unsaturated Saturated hydrocarbons – all single covalent bonds between carbons (saturated with the most single bonds it can make) Unsaturated - have at least one double or triple covalent bond between carbons (eg, ethene, double) (eg, propyne, triple)
Substituted Hydrocarbons – have another element (other than H and C) in the compound
Because of the double bond(s), alkenesare much more reactive than alkanes.