Organic Chemistry Chapter 6 Flashcards

Questions and Answers

What is an addition reaction?

Two reactants add together to form a single product. (correct)

A single reactant reorganizes its bonds.

A single reactant splits into two products.

Two reactants exchange parts to give two new products.

What is an example of an addition reaction?

Ethene (C2H4) + hydrobromic acid (HBr) >> C2H5Br

What happens during an elimination reaction?

A single reactant splits into two products. (correct)

A single reactant reorganizes its bonds.

Two reactants add together.

Two reactants exchange parts.

Provide an example of an elimination reaction.

Ethanol (C2H5OH) + acid catalyst >> C2H4 + H2O Signup and view all the answers

What do substitution reactions involve?

Two reactants exchange parts to create new products. Signup and view all the answers

What is an example of a substitution reaction?

Methane (CH4) + Cl2 >> chloromethane (CH3Cl) + hydrochloric acid (HCl) Signup and view all the answers

Rearrangement reactions involve splitting a single reactant into multiple products.

False Signup and view all the answers

What is an isomer?

Same molecular formula, different chemical structures. Signup and view all the answers

What is a mechanism in chemistry?

Detailed step by step description to explain what is happening in a chemical reaction. Signup and view all the answers

In a reaction, specific bonds are _____ in reactant molecules.

broken Signup and view all the answers

In a reaction, specific bonds are _____ in product molecules.

formed Signup and view all the answers

What are the two ways to break covalent bonds?

Homolytic and heterolytic cleavage. Signup and view all the answers

What characterizes homolytic cleavage?

One electron remains with each product fragment. Signup and view all the answers

What does heterolytic cleavage result in?

Both bonding electrons move with one fragment. Signup and view all the answers

What are the two ways to form covalent bonds?

Homogenic and heterogenic formation. Signup and view all the answers

What is characteristic of radical reactions?

They involve symmetrical bond breaking. Signup and view all the answers

What defines a nucleophile?

An atom that can donate a pair of electrons to a positively polarized, electron-poor atom. Signup and view all the answers

Provide examples of nucleophiles.

Ammonia, water, hydroxide ion, chloride ion. Signup and view all the answers

What is an electrophile?

A positively polarized, electron-poor atom that accepts a pair of electrons. Signup and view all the answers

Provide examples of electrophiles.

Acids, alkyl halides, and carbonyl compounds. Signup and view all the answers

What is a carbocation?

Positively charged species; electrophile that can accept an electron pair from a nucleophile. Signup and view all the answers

What does Delta G represent?

The energy change that occurs during a chemical reaction. Signup and view all the answers

What is the Gibbs free energy equation?

Free energy of products - free energy of reactants. Signup and view all the answers

What does the equilibrium constant equation represent?

([C][D])/([A][B]) Signup and view all the answers

What characterizes exergonic reactions?

Delta G has a negative value. Signup and view all the answers

What characterizes endergonic reactions?

Delta G has a positive value. Signup and view all the answers

What is enthalpy change?

Delta H; heat of reaction; measure of the total change in bonding energy during a reaction. Signup and view all the answers

What characterizes an exothermic reaction?

It releases heat. Signup and view all the answers

What characterizes an endothermic reaction?

It absorbs heat. Signup and view all the answers

What does entropy change represent?

Delta S; change in molecular randomness during a reaction. Signup and view all the answers

What does a negative delta S indicate?

Randomness decreases. Signup and view all the answers

What does a positive delta S indicate?

Randomness increases. Signup and view all the answers

What is bond dissociation energy?

The amount of energy needed to break a given bond to produce two radical fragments in the gas phase. Signup and view all the answers

Study Notes

Types of Reactions

Addition Reactions: Involve combining two reactants to form a single product, with no leftover atoms.
Example: Ethene (C2H4) plus hydrobromic acid (HBr) yields bromethane (C2H5Br).
Elimination Reactions: A single reactant breaks down into two products, typically producing a small molecule like water.
Example: Ethanol (C2H5OH) with an acid catalyst leads to ethene (C2H4) and water (H2O).
Substitution Reactions: Two reactants swap parts, resulting in two new products.
Example: Methane (CH4) reacts with chlorine (Cl2) to produce chloromethane (CH3Cl) and hydrochloric acid (HCl).
Rearrangement Reactions: A single reactant reorganizes its bonds and atoms to form an isomeric product.

Key Concepts

Isomer: Compounds with the same molecular formula but different structures.
Mechanism: The detailed process outlining what occurs during a chemical reaction.

Bond Interactions

Bond Breaking: Involves specific bonds in reactant molecules being broken.
Bond Formation: Specific bonds in product molecules are formed.
Covalent Bond Cleavage: Consists of homolytic (symmetrical) and heterolytic (unsymmetrical) cleavage.
Homolytic Cleavage: Each product fragment retains one electron, creating radicals.
Heterolytic Cleavage: One fragment retains both bonding electrons, leading to an empty orbital in the other fragment.
Bond Formation: Can be homogenic (one electron from each reactant) or heterogenic (both electrons from one reactant).

Reaction Types

Radical Reactions: Occur through symmetrical bond breaking and forming; radicals are highly reactive due to unpaired electrons.
Polar Reactions: Arise from unsymmetrical bond breaking and forming; common due to the attraction between polar functional groups.

Polarity and Charge

Polarity: Determined by electronegativity differences across atoms.
Carbon-Halogen Bonds: Carbon bonded to halogens carries a partial positive charge (S+).
Carbon-Metal Bonds: Carbon linked with metals carries a partial negative charge (S-).

Polarizability

Definition: Refers to the change in electron distribution around an atom due to surrounding electric fields; larger atoms with loosely held electrons are more polarizable.

Radical Reactions Steps

Consist of three phases: initiation, propagation, and termination.

Nucleophiles and Electrophiles

Nucleophile: Electron-rich species capable of donating electron pairs; examples include ammonia, water, hydroxide ion, and chloride ion.
Electrophile: Electron-poor species seeking to accept electron pairs; examples include acids, alkyl halides, and carbonyl compounds.
Carbocation: Positively charged intermediate that acts as an electrophile, accepting electron pairs from nucleophiles.

Thermodynamics of Reactions

Gibbs Free Energy (ΔG): Indicates energy changes during reactions; calculated as free energy of products minus free energy of reactants.
Equilibrium Constant: Expressed as ([C][D])/([A][B]).
Exergonic Reactions: Favorable reactions with negative ΔG; energy released to surroundings.
Endergonic Reactions: Unfavorable reactions with positive ΔG; energy absorbed from surroundings.
Enthalpy Change (ΔH): Represents heat change; exothermic reactions release heat (negative ΔH), while endothermic reactions absorb heat (positive ΔH).
Entropy Change (ΔS): Indicates molecular randomness during reactions; positive ΔS signifies increased randomness, while negative ΔS indicates decreased randomness.

Bond Energy

Bond Dissociation Energy: The energy required to break a specific bond into two radical fragments in the gas phase.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Explore key concepts from Organic Chemistry Chapter 6 with these flashcards. This chapter focuses on addition and elimination reactions, including examples and definitions that illustrate the principles of these reactions. Perfect for students aiming to reinforce their understanding of organic reactions.