Organic chem wace Flashcards
What defines homologous series
-similar structure
-similar chemical properties
-same general formula
-pattern to their physical properties
Define an alkane. Formula? Saturation?
Hydrocarbon containing only single bonds. All carbon-carbon are covalent, single bonds.
- CnH2n+2
-saturated
Define structural isomers
same molecular formula but different structural formula
Describe the melting/boiling point of alkanes.
What occurs to BP with straight chains in contrast to branched
-increase with more carbon atoms in formula (increase length)
-increase atoms=greater intermolecular (dispersion) forces
-greater intermolecular forces=increased energy to separate molecules
-increased energy required=increased BP
Straight have increased interaction than branched. Greater branching=decreased BP
Describe the solubility of alkanes
Nonpolar. Immiscible in water
Soluble in most organic solvents (like dissolves like)
Define an alkene. Formula? Saturation?
Contain a double bond
-CnH2n
-unsaturated therefore addition can occur
-both structural and geometric isomers
Describe the structural and geometric isomers of alkenes
Structural
Differentiate in bond positioning, branching
Geometric
Stereoisomerism occurs due to restricted rotation of double bond
Cis: same side atom
Trans: different side atom
Define an isomer
Different physical but same chemical properties due to similar molecular masses
Describe the melting/boiling point of alkenes.
Solubility?
BP increases at increase in carbon atoms in formula
Greater branching = lower BP
Solubility: miscible in organic
Describe alcohol as a functional group
- Has an OH group attached to C atom
- can classify as primary, secondary, or tertiary according to position of OH on carbon skeleton
-Name suffix (ol) or prefix (hydroxy)
Describe aldehyde as a functional group
- Has C=O group at end of carbon chain
-polar molecules
-Name suffix (al)
Describe ketone as a functional group
- Has a C=O group next door to 2 carbons
-polar molecules
-name suffix one
-number may be used before -one to indicate first carbon involved
Describe carboxylic acid as a functional group
-Has OH and C=O groups at same carbom atom
-this COOH group must be at end of chain
-can form H bonds between molecules
-name suffix (oic acid)
Describe ester as a functional group
-one oxygen is part of C=O bond, other is next door, sandwiched between 2 carbons
-made by reacting alcohol with carboxylic acid
-name suffixs yl (first) and oate (second)
Describe amine as a functional group
-has an NH2 group attached to carbon chain
-name suffix (amine) prefix (amino)
Describe amide as a functional group
-has NH2 group and C=O bond
-both functional groups are on same carbon
-name suffix (amide)
How to denote naming amine prefix’s
-if 2x identical groups present (prefix=di)
-if3x identical groups present (prefix=tri)
e.g. dipropanamine
How to name an amine with 2x different alkyl groups present
alphabetically listed
e.g. ethylmethanamine, ethyldiproanamine
How to name an amine if other functional groups are present in molecule
presence of amine groups denoted using amino
e.g. 2-aminoethanoic acid
Memorise the nomenclature list and write down (order of highest–>lowest priority)
Carboxylic acid (suff-oic acid) (pre-carboxy)
Ester (oate) (alkoxy carbonyl)
Amide (amide) (amido)
Aldehyde (al) (formyl)
ketone (one) (oxo)
Alcohol (ol) (hydroxy)
Amine (amine) (amino)
Alkane (ane) (alkenyl)
Alkene (ene) (alkyl)
Akylhalide only pre-halo
Describe the boiling point of alcohols, carboxylic acid, amine and amide
All able to form hydrogen bonds
-NOF attached to hydrogen and lone pairs of self
-strong h bond gives all groups a higher bp than an alkane of similar mass
-increase length of carbon chains increase bp
-due to increase size of molecule allowing for stronger dispersion forces
-more energy required to overcome forces
What occurs to the bp of primary, secondary and tertiary alcohols
decreases from prim–>tertiary
- carbon chain restricting H bond formation with other molecules
Describe the solubility of alcohols, carboxylic acid, amine and amide
In water
Small groups able to dissolve in water due to ability to form H bonds with water molecules
- increase chain length= decrease solubility
-disrupts formation of H bonds
-molecule becomes more non-polar
In organic solvents
non-polar therefore increase carbon chain length will increase solubility (as long chain=non-polar)
more dispersion forces can be formed w/long chain however, will not be as strong as H bonds
Describe the boiling point of aldehydes, ketones and esters
Only able to form dipole-dipole forces
-have no NOF on self hydrogen bonds
-increase BP than alkanes as dipole-dipole forces are stronger than dispersion
-increase chain length will increase bp as large molecule, with large molecular mass, allows for increase in dispersion forces
Describe the solubility of ketones, aldehydes and esters
In water
Although no H bonds with own molecule, small chains can form H bonds with water=soluble
- increasing length will decrease solubility in water due to increased non-polarity of molecule
In organic solvent
non-polar therefore increase carbon chain length will increase solubility (as long chain=non-polar)
more dispersion forces can be formed w/long chain however, will not be as strong as H bonds
