Carbonyl compounds and their physical properties Flashcards
the carbonyl group is
C=O
carbon atom joined by a double bond to an oxygen atom
the two types of carbonyl compounds are
ketones and aldehydes
aldehydes have the C=O group in the ………part of the carbon chain meaning there is/ is not a hydrogen atom joined to the carbonyl group
end
-there is a hydrogen joined to the group
H-C=O
ketones have the C=O group in the…..part of the chain meaning there is/ is not a hydrogen atom joined to the carbonyl group
‘middle’ or any carbon not on the end of the chain
-there is NO hydrogen atom joined to the group
C=O
for aldehydes, if locants are used, then the carbon of the carbonyl group is carbon no. …. in the chain
carbon 1
the general formula of aldehydes is
RCHO
the general formula of ketones is
RCOR
the double bond in the carbonyl group is made up of
a pi and sigma bond
the C=O bond is polar/ non-polar because
polar because of the differing electronegativities of carbon and oxygen
in the carbonyl compound the electron density is greater near the ……… atom
oxygen atom
some physical properties of aldehydes are
they have distinctive smells
the order of highest to lowest boiling temperatures for ketones, alkanes, aldehydes and alcohols is:
Highest: alcohol
ketones
aldehydes
Lowest: alkanes
the lower aldehydes and ketones are …………….. in water because
soluble because they can form hydrogen bonds with H2O molecules, but their solubility decreases with increasing carbon chain length
aldehydes with shorter carbon chains had…………..smells while longer chains have……………smells
short: unpleasant, such as butanal which smells of rancid butter
longer: very pleasant, such as nonanal (9 C atoms) smells of roses
lower ketones smell of
solvents, and propanone is widely used as a solvent such as nail varnish remover
