Chemistry Exam 3

chapter 9 - 13

Alcohol

Alcohol

Ether

Aldehyde

Ketone

Carboxylic Acid

Ester

Amide

Amine

Methane

CH₄

Ethane

C₂H₆

Propane

C₃H₈

Butane

C₄H₁₀

Pentane

C₅H₁₂

Hexane

C₆H₁₄

Heptane

C₇H₁₆

Octane

C₈H₁₈

Nonane

C₉H₂₀

Decane

C₁₀H₂₂

London Dispersion Force (LDF)

• larger cloud = stronger force

• more surface area = stronger force

dipole-dipole

• greater separation of positive and negative charges = stronger attractions

• orientation: positive end needs to attract a negative end

dipole induced dipole

• stronger dipole moment = stronger force

• larger atom = stronger force (more polarizable)

ion induced dipole

• higher charges = stronger forces

• larger atoms = stronger forces (more polarizable)

ion-ion

• greater charge = stronger force

• closer together = stronger interaction

High melting and boiling point

stronger IMFs; more energy is required to break the interaction

Low melting and boiling point

weak IMFs; less energy needed to overcome the forces

Polarizability

how easily an electron cloud can be distorded

induced dipole

a temporary dipole created in a nonpolar molecule due to an external electric field or nearby charge; causes the electron cloud to shift and creates a region of partial positive charge and a region of partial negative charge

Solids

Molecular Structure: closely packed, don’t freely move

IMF: strongest, keep molecules in a fixed shape and volume

KE: low

Liquids

Molecular Structure: close but not fixed arrangement

IMF: weaker but strong enough to keep molecules near each other; allows for a defined volume but not a fixed shape

KE: molecules can partially overcome IMF enabling movement but not seperation

Gases

Molecular Structure: far apart in constant random motion

IMF: weak and often negligible

KE: high, allowing to completely overcome IMF allows free movement in all directions

Intramolecular Force

forces that hold atoms together within a molecule forming chemical bonds

• covalent, ionic, and metallic bonds

breaking requires a chemical reaction and are in the range of 100-1000 kJ/mol

Intermolecular Force (IMF)

forces of attraction between separate molecules

• LDR, Dipole-Dipole, hydrogen bonds

determine physical changes rather than breaking apart

• forces range from 1-50 kJ/mol

Alkane

C_nH_2n+2

saturated with single bonds

• strong and nonpolar

• combustion and substitution reactions

• high stability

Alkene

C_nH_2n

Unsaturated with at least one double bond

• addition reactions

• less stable than alkanes

Alkyne

C_nH_2n-2

Unsaturated with at least one triple bond

• addition reactions

• less stable than alkenes and alkanes

Aromatic

a ring of carbon atoms with alternating single and double bonds

• electrophilic substitution reactions

• high stability makes them less reactive

Isomer

a molecule that shares the same molecular formula as another molecule but differs in the arrangement

Geometric Isomer

some molecular formula and some connectivity but different arrangements

• look for restricted rotation (double bonds or rings)

Constitutional Isomer

same molecular formula but atoms are connected differently

• atoms bonded in different orders