Introduction to Polymers

Podcast

Play an AI-generated podcast conversation about this lesson

Download our mobile app to listen on the go

Get App

Questions and Answers

Which statement most accurately describes the role of a free radical in the initiation step of addition polymerization?

The free radical facilitates the abstraction of hydrogen atoms from monomers, creating reactive carbenes.
The free radical's unpaired electron breaks open the double bond in a monomer, forming a new radical. (correct)
The free radical acts as a terminating agent, combining with monomers to halt chain propagation.
The free radical donates electrons to stabilize double bonds, preventing premature polymerization.

In condensation polymerization, the byproduct formed is exclusively water.

False (B)

Explain the mechanistic differences between thermal cracking and catalytic cracking in the context of alkane decomposition, with specific reference to energy requirements and product selectivity.

Thermal cracking involves high temperatures and pressures to break C-C bonds, resulting in a random mixture of smaller alkanes and alkenes. Catalytic cracking uses lower temperatures and pressures with a catalyst to selectively produce specific alkenes and branched alkanes.

In the context of elimination reactions, the preferential formation of the most substituted alkene is rationalized by ______'s rule, which hinges on the thermodynamic stability of the resulting alkene.

Zaitsev Signup and view all the answers

Match the following reaction types with their corresponding general descriptions:

Addition Reaction = Involves the combination of two or more reactants to form a single product, typically at an unsaturated site. Elimination Reaction = Involves the removal of atoms or groups of atoms from a molecule, leading to the formation of a multiple bond. Substitution Reaction = Involves the replacement of one atom or group of atoms in a molecule with another atom or group. Condensation Reaction = Involves the joining of two molecules with the loss of a small molecule, such as water. Signup and view all the answers

Which factor primarily determines the strength of London dispersion forces between two nonpolar molecules?

The polarizability, influenced by the size and shape, of each molecule. (B) Signup and view all the answers

A tertiary alcohol will undergo SN1 reaction faster than a primary alcohol.

True (A) Signup and view all the answers

Describe the key differences in the reaction conditions required for SN1 versus SN2 reactions, specifying solvent polarity, nucleophile strength, and substrate structure.

SN1 reactions favor polar protic solvents to stabilize the carbocation intermediate, weak nucleophiles, and tertiary substrates to facilitate carbocation formation. SN2 reactions require polar aprotic solvents to avoid hindering the nucleophile, strong nucleophiles, and primary substrates to minimize steric hindrance. Signup and view all the answers

In mass spectrometry, the ______ peak represents the intact molecular ion and provides crucial information about the molar mass of the compound.

molecular ion Signup and view all the answers

Match the following spectroscopic techniques with the type of molecular information they primarily provide:

Infrared (IR) Spectroscopy = Identifies functional groups based on vibrational modes. Nuclear Magnetic Resonance (NMR) Spectroscopy = Provides detailed information about the carbon-hydrogen framework and connectivity of a molecule. Mass Spectrometry (MS) = Determines the molar mass and fragmentation pattern of a molecule. Ultraviolet-Visible (UV-Vis) Spectroscopy = Examines electronic transitions and provides information about conjugated systems. Signup and view all the answers

Which experimental technique is most effective for distinguishing between enantiomers?

Polarimetry. (D) Signup and view all the answers

Alkanes are more reactive than alkenes due to the presence of sigma bonds.

False (B) Signup and view all the answers

Explain how increased branching in an alkane affects its boiling point, and relate this effect to changes in intermolecular forces.

Increased branching reduces the surface area available for intermolecular contact, weakening London dispersion forces. This decrease in intermolecular attraction leads to a lower boiling point. Signup and view all the answers

The addition of HBr to an unsymmetrical alkene will proceed via ______'s rule, where the hydrogen atom attaches to the carbon with more hydrogen atoms already attached

Markovnikov Signup and view all the answers

Match the types of structural isomers with their corresponding description:

Chain Isomers = Same molecular formula but differ in the arrangement of the carbon chain Positional isomers = Same molecular formula but differ in the position of a functional group or substituent on the same structure Functional isomers = Same molecular formula but differ in having different functional groups in the structure Signup and view all the answers

Which of the following is the primary reason for the high flammability of organic compounds?

Their exothermic reaction with oxygen to produce carbon dioxide and water. (A) Signup and view all the answers

Esters are functional group isomers with ketones.

False (B) Signup and view all the answers

Describe the step-by-step mechanism of an SN1 reaction.

Step 1: Leaving group departs to form a carbocation intermediate. Step 2: Nucleophile attacks the carbocation, forming a new bond. Signup and view all the answers

The process of converting long hydrocarbon chains into shorter, more usable chains is known as ______.

cracking Signup and view all the answers

Match the functional groups with the appropriate suffix used in IUPAC naming:

Alcohols = -ol Aldehydes = -al Ketones = -one Carboxylic acids = -oic acid Signup and view all the answers

Flashcards

What are Polymers?

Large organic molecules made of hundreds or thousands of atoms, composed of repeated smaller units called monomers.

What are Monomers?

Small organic molecules that can be covalently bonded to each other in a repeating pattern to form a polymer.

What is Addition Polymerization?

Polymers joining two or more monomers with double bonds (unsaturated) to form long single-bonded chains.

What is Condensation Polymerization?

Polymerization when two different monomers with functional groups on both ends react, eliminating a water molecule.