This chemistry question involves key chemical concepts and calculations. The detailed solution below walks through each step, from identifying the reaction type to computing the final answer.
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(1) Addition polymerization of alkenes Addition polymerization of alkenes is a chain-growth process where multiple alkene molecules (monomers with C=C double bond) link together by opening the double bond, forming a long chain polymer without loss of any small molecule byproduct. Typical mechanism: Free radical addition polymerization. General reaction for ethene (a common alkene): n \ CH_2=CH_2 initiator [ -CH_2-CH_2- ]_n Steps: Initiation: Peroxide initiator decomposes to radicals. (R-O)_2 → 2 \ R-O^ R-O^ + CH_2=CH_2 → R-O-CH_2-CH_2^ Propagation: Radical adds to monomer repeatedly. R-O-(CH_2-CH_2)_n ^ + CH_2=CH_2 → R-O-(CH_2-CH_2)_n+1 ^ Termination: Radicals combine. R-O-(CH_2-CH_2)_m ^ + R-O-(CH_2-CH_2)_p ^ → R-O-(CH_2-CH_2)_m+p-O-R Three monomers (alkenes): Ethene (CH_2=CH_2), propene (CH_2=CH-CH_3), but-1-ene (CH_2=CH-CH_2-CH_3). (2) Chain reaction representing typical homopolymer situation Homopolymer: Polymer formed from one type of monomer only. Typical situation: Free radical addition polymerization of an alkene (e.g., ethene to polyethylene). Chain reaction has three main steps: Initiation: Peroxide decomposes: Bz_2O_2 → 2 \ BzO^ (Bz = C_6H_5CH_2) Radical adds to monomer: BzO^ + CH_2=CH_2 → BzO-CH_2-CH_2^ Propagation: BzO-CH_2-(CH_2-CH_2)_n-1-CH_2 ^ + CH_2=CH_2 → BzO-CH_2-(CH_2-CH_2)_n -CH_2 ^ Termination (combination): BzO-(CH_2-CH_2)_m ^ + BzO-(CH_2-CH_2)_n ^ → BzO-(CH_2-CH_2)_m+n-OBz This represents homopolymerization as only one monomer (ethene) is used. (3) Difference between polymerization and condensation | Polymerization (Addition) | Condensation | |-------------------------------|------------------| | Monomers link by addition across multiple bond (e.g., C=C). | Monomers link by elimination of small molecule (e.g., H_2O). | | No byproduct. | Byproduct formed. | | Chain-growth, fast. | Step-growth, slower. | | Example: n \ CH_2=CH_2 → [-CH_2-CH_2-]_n (polyethene). | Example: HO-(CH_2)_4-OH + HOOC-(CH_2)_4-COOH → [-O-(CH_2)_4-OOC-(CH_2)_4-CO-]_n + (2n-1) H_2O (nylon 6,6). | Difference between homopolymers and copolymers Homopolymers: Formed from a single type of monomer. All repeating units identical. Example: Polyethene [-CH_2-CH_2-]_n from ethene only. Copolymers: Formed from two or more different monomers. Repeating units vary. Example: Styrene-butadiene rubber (SBR): [-CH(CH_3)-CH_2-] from propene? Wait, styrene C_6H_5CH=CH_2 and buta-1,3-diene CH_2=CH-CH=CH_2. Types of copolymers: Random, alternating, block, graft. See above explanations