o chem exam 3

What is the term for a reaction that absorbs energy and has a positive change in enthalpy?

Endothermic

What is the term for a reaction that releases energy and has a negative change in enthalpy?

Exothermic

What type of carbocation is the most stable?

Tertiary carbocation

What are the two key products of an E2 reaction?

Alkene and a leaving group

What is the main difference between SN1 and SN2 reactions regarding the stereochemistry of the products?

SN2 causes inversion; SN1 produces racemic mixtures

What is Zaitsev's Rule?

The most stable alkene formed will have the most substituent groups bonded to the alkene carbons.

What is a nucleophile?

A species that donates an electron pair to form a chemical bond.

What is the product of a tautomerization reaction involving a ketone and an enol?

Interconversion between a keto form (ketone) and enol form.

In an acid-base reaction, what is the term for the species that loses a proton?

Acid

What is the significance of pKa in determining the strength of an acid?

Lower pKa values indicate stronger acids.

How many stereoisomers will a compound with 3 chiral centers have?

8 stereoisomers, according to the 2n rule (where n = number of chiral centers).

What is the term for the highest energy state during a reaction that leads to a transition from reactants to products?

Transition state.

Define carbanion.

A negatively charged carbon atom.

What is the role of a Lewis Acid in a reaction?

To accept an electron pair.

What must be true for a compound to be considered chiral?

It must have at least one chiral center (a carbon bonded to four different groups).

What does the term 'intermediate' refer to in a reaction mechanism?

A species that forms from reactants and converts to products, existing transiently during the reaction.

In an addition reaction, what does Markovnikov's Rule state?

The electrophile will add to the more stable (more substituted) carbocation.

What is an Arrhenius acid?

A substance that increases the concentration of H⁺ ions in solution.

What are conjuagte acid-base pairs?

Two species that differ by the presence of one proton.

What is a typical characteristic of E1 and SN1 reactions?

Both involve the formation of a carbocation intermediate.

What defines a polar protic solvent?

A solvent that can form hydrogen bonds, typically containing -OH or -NH groups.

What is the term for a reaction in which two molecules combine to form a single product?

Synthesis reaction.

What does the term 'oxidation' refer to in a chemical reaction?

The loss of electrons or an increase in oxidation state.

What is a common characteristic of Lewis bases?

Lewis bases donate electron pairs.

What does the term 'end product' refer to in chemical reactions?

The final products formed after all reactions have occurred.

What is the role of a solvent in a chemical reaction?

To dissolve reactants and facilitate their interaction.

Define electrophile.

A species that accepts an electron pair to form a chemical bond.

What type of reaction involves the breakdown of a compound into simpler components?

Decomposition reaction.

What is the significance of the reaction mechanism?

It describes the step-by-step sequence of events in a chemical reaction.

What type of hydrocarbons consist only of single bonds?

Saturated hydrocarbons.

What is the term for the minimum energy required to initiate a chemical reaction?

Activation energy.

What is the term for the process where atoms share pairs of electrons?

Covalent bonding.

What are the three main types of chemical bonds?

Ionic, covalent, and metallic bonds.

What does the term 'lewis structure' refer to?

A diagram that shows the bonding between atoms and the lone pairs of electrons in a molecule.

What is a characteristic of an ionic bond?

It involves the transfer of electrons from one atom to another.

What is the difference between a strong acid and a weak acid?

Strong acids completely dissociate in solution, while weak acids partially dissociate.

Define the term 'reaction rate.'

The speed at which reactants are converted into products in a chemical reaction.

What is a catalyst?

A substance that increases the rate of a reaction without being consumed.

What is the law of conservation of mass?

Mass is neither created nor destroyed in a chemical reaction.

What is temperature's effect on reaction rate?

Increasing temperature typically increases the reaction rate.

What are isomers?

Compounds with the same molecular formula but different structures.