organic Flashcards
Structural vs Chain vs Positional Isomers
- Structural Isomers - same molecular formula but different structures
- Chain Isomers - main chain length is changed
- Positional Isomers -exist when position of a branch changes
Dispersion forces definition
Defined as weak IMFs that occur in non-polar species due to the formation of temporary dipoles which then induce temporary dipoles in the surrounding species
Why do longer alkanes have greater dispersion forces
because of increased electrons
Why do straight chain alanes possess stronger dispersion forces than branched alkanes
Their shape allows maximum surface contact between the molecules
Why does cis/trans geometric isomerism exist
Exists due to inability to rotate around the double bond
Why are alkanes dispersion forces slightly more stronger than alkenes
due to stereochemistry
Aldehydes functional group + atoms + suffix
Functional group: -CHO (carbonyl - on terminal carbon)
suffix: -al
Dipole-dipole forces definition
- the electrostatic attraction between oppositely charged ends of the overall dipole ,increasing in strength, with the difference in electronegativities between atoms of the molecules
Why does longer chain length aldehydes increases melting and boiling points
Increases the amount of electrons, increasing dispersion forces which then then add to the strength of the sum total intermolecular forces taking place between aldehyde molecules
Alcohols functional group + atoms + suffix
- Functional group: -OH (hydroxyl)
- Suffix: -ol
H-bonding defintion
- Hydrogen bonding is an extreme form of dipole-dipole forces that only occurs when a hydrogen atom bonded to N, O or F interacts with a non-bonding pair of electrons on another N,O or F - either on the same molecule or different polar molecules
- H-bonding is due to the highly electronegative negative nature of fluorine, oxygen, nitrogen that have a high charge density due to their relatively small size
Why do primary alcohols have higher BP + MP than secondary alcohols than tertiary alcohols
Due to the exposure of the hydroxyl
Ketones functional group + atoms + suffix
- Functional group: -C=O (carbonyl - on non-terminal carbon)
- Double bond oxygen
- Suffix: -one
Carboxylic Acid functional group + atoms + suffix
- Functional group: -COOH (carboxyl) on the first carbon
- Suffix: -oic acid
Why does solubility in polar substances decrease with increasing chain length
This is because dispersion forces become more significant, preventing solvation in polar substances thus, they then become more soluble in non-polar substances