Alcohols Functional group Flashcards
What is this group called
C=O
Carbonyl group
any skeletal that has a carbon double bond bonded to Oxygen
(carbon oxygen double bond)
What’s an Aldehyde?
when the molecule is bonded to C=O and the same carbon is bonded to a H or double H H
=. HCOH / COH
1) What’s the general formula of an aldehyde?
2) so what’s the general formula if it had 3 carbons?
1) CnH2nO
2) C3H6O
Out of these molecules, what is an aldehyde?
A & C
How do we write the structural formula of this molecule?
CH3CH2CHO
(for aldehydes, we always write the hydrogen first then the oxygen so that we don’t get the aldehyde confused for an alcohol as an alcohol is OH
What’s this R group referred to?
R is to represent different group of atoms,
in aldehydes it represents an alkyl group
R= e.g. CH3CH2CH2CH2
which of these represents an aldehyde?
B & C
=O =
Name this aldehyde
It has 3 carbons in the longest chain
•Prefix - Prop
And suffix is Anal for all aldehyde
“= Propanal
Name this molecule
Hexanal
What’s the name of this molecule?
and what’s it known for
Methanal but also known as formaldehyde
What are ketones?
Ketones are when it’s in the middle and bonded to 2 carbons e.g
which of these molecules are ketones?
B and C
What is the general formula for ketones?
CnH2nO
Write the structural formula for this ketone
CH3COCH3
as u can see it’s between 2 carbons making it a ketone
How to write this if they’re not identical?
RCOR”
“ shows it may be different to the first R
Name this ketone
Pentanone
Count the long chain = pentane add the suffix = anone C=O is on the second carbon (always choose the lowest position number) pentan-2-one
Name this ketone
Hexan-3-one
Name this molecule
this molecule is an aldehyde as ketone is never at the end of the carbon as it has to be in between 2 carbons
name = pentanal
Why don’t we include position numbers for ethanol and methanol in alcohol?
we don’t include position numbers for methanol or ethanol because the hydroxyl or alcohol group is always on the first carbon
Why don’t we include position numbers for these molecules and identify what type of molecule it is
They are ketones,
the reason why is because we choose the lowest number so the first compound will always stay the same so we name is propanone
and the second will always stay (lowest position number is second carbon) we name is = butanone
What’s the suffix of ketones and suffix of aldehyde?
Suffix of ketones - Anone
suffix of aldehyde- Anal
what are carboxylic acids
when Carbon bond is double bonded to O and single bonded to an OH
= COOH
1) When bonded to HCOOH or COOH what do we call it?
2) and when it has no other functional group what do we refer to these compound
1) Carboxylic acid
2) part of the carboxylic acid homologous series
which of these molecules are carboxylic acids
A&B
What’s the general formula of carboxylic acid and what’s it when bonded to 3 carbons is
CnH2n+1COOH
3 carbons = C2H5COOH
what’s the structural formula of this atom
CH3CH2COOH
Name this carboxylic acid
propanoic acid
as the suffix for all carboxylic acid is anoic acid
the carbonyl group C=O and the hydroxyl group C-OH are always at the end of the chain so no position number is required
Because we are drawing an aldehyde where should we add the carbonyl group to?
1 and 4 as aldehydes are only at the end of front.
how’s pentan-2-one drawn in it’s skeletal formula?
draw skeletal formula of butanone
anone- ketone so it must be surrounded with 2 carbons
it can look like 2 ways
draw Propanoic acid
- draw the number of carbons
- draw carbonyl group at the end of chain
- add an OH chain next to the end of C=O
In carbonyl compounds, what do all Aldehyde, Ketones and carboxylic acid have in common?
They all have van der waals forces and dipole dipole
Hydrogen bonding only occurs if it’s covalently bonded to what elements?
So what carbonyl compound would have hydrogen bonding?
FON Fluorine Oxygen and Nitrogen the compound carboxylic acid would have hydrogen bonding due to the OH bonding
For carbonyl compounds with the same number of carbons, we would expect the melting and boiling points of…
Ketones and aldehydes to be similar
Carboxylic acids to be higher than both ketones and aldehyde
As the length of carbon chain increases in carbonyl compounds, the…
strength of van der waals forces increases so melting and boiling point increases
What’s the rule of thumb with polar bonds?
Likes dissolves like
so polar bonds dissolve in polar substances
and non polar bonds dissolve in non polar substances
All carbonyl compounds are polar,
why is that?
because the C-O bond being polar
Carbon is less electronegative than oxygen so the delta positive charge will be on the carbon atom whilst the Oxygen has the negative one
What would be expect of carbonyl compounds?
Because they are all polar bonds (due to carbonyl group C=O) we would expect them to dissolve in water as water is polar
so we’d expect them to be highly soluble in water
So as the length increases the more non polar bonds there are so solubility decreases
so only small molecules are highly soluble in water
because carboxylic acids have a hydroxyl group that can form hydrogen bonding
what would we expect?
we would expect it to be more soluble than ketones and aldehyde
