Organic chem - 3 Flashcards
Define chloroalkanes
A chloroalkane is an alkane where one or more of the hydrogen atoms have been replaced by chlorine atoms.
Do chloroalkanes occur naturally?
No
5 main uses of chloroalkanes
- Solvents to remove oil
- Grease in the dry cleaning
- Solvents in the paints industry
- Coolants in air conditioning
- Propellants in aerosols
Why is the use of chloroalkanes being reduced?
As thy destroy the ozone layer.
Draw and give the molecular formula of chloromethane
- CH3Cl
Draw and give the molecular formula of dichloromethane
CH₂Cl₂
Draw and give the molecular formula of trichloromethane
CHC3
Give the common name for trichloromethane
Chloroform
What is trichloromethane used for?
- An early anaesthetic
Is chloroform/trichloromethane polar or non-polar
Non-polar
Draw and give the molecular formula of tetrachloromethane
CCl4
What could one Cl atom destroy?
1,000,000 ozone molecules
What could two Cl atoms destroy?
2,000,000 ozone molecules
What is the first thing to do in naming larger chloroalkanes?
Select the longest carbon chain to give the parent alkane.
What do you number from in naming larger chloroalkanes?
From whichever end of the molecule gives the lowest possible number to the carbon atom to which the chlorine atom is attached.
What is important to do if more than one chlorine is attached?
Use the appropriate prefix - di, tri, tetra
Are chloroalkanes polar or non-polar?
Non-polar
Are chloroalkanes soluble or insoluble in water?
Insoluble
Why are chloroalkanes insoluble in water?
As they are non-polar
Why are chloroalkanes used in the dry cleaning industry?
As they remove oil stains.
Do chloroalkanes have high or low boiling points?
Low boiling points>?
Are chloroalkanes soluble in non-polar solvents?
Yes
Name a non-polar solvent that chloroalkanes are soluble in.
Cyclohexane
What forces of attractions do chloroalkanes have?
Van der Waals forces of attraction
What are chloroalkanes proven to damage?
The ozone layer
Primary alcohols – oxidised –>
Aldehyde
Primary alcohols –oxidised–> Aldehydes –oxidised–>
Carboxylic acid
Colour of Cr + 6 =
Bright orange
Colour Cr + 3 =
Green
Draw and give the molecular formula of propan-1-ol.
Drawn
What is the molecular formula of Sodium dicromate6
Na₂Cr₂O7
What is Na2Cr2O7 in the reaction?
Oxidising agent
Secondary alcohol –oxidised–>
Ketones
What would happen without acid?
Nothing
Define alcohols
An alcohol is an alkane where one of the hydrogens is replaced with -OH group.
What is the -OH group called?
Hydroxyl group
What is the functional group of alcohols?
Hydroxyl group
What is the general formula of alcohols?
C(n)H(₂n+1)OH
What shape are all the carbon atoms in alcohols?
Tetrahedral
What shape is the -OH group of alcohol?
V-shaped
Is the -OH group of alcohols polar or non-polar?
Polar
Is the carbon chain (other than -OH) polar or non-polar?
Non-polar
What is replaced at the end of alcohols and what is it replaced with?
- ane is replaced with anol
Name 3 examples of alcohols
- Methanol
- Ethanol
- Propanol
Which carbon chain is chosen when naming alcohols?
The longest
What are end are carbons named from?
The end that gives the carbon atom with the -OH group attached the smallest possible number
What determines the direction in alcohols?
The position of the hydroxyl functional group.
Draw and give the molecular formula of methanol
CH3OH
Draw and give the molecular formula of ethanol
C₂H5OH
Draw and give the molecular formula of propan-1-ol
C3H7OH / CH3CH₂CH₂(OH)
Draw and give the molecular formula of propan-2-ol
C3H7OH / CH3CH(OH)CH3
Draw and give the molecular formula of butan-1-ol
C4H9OH / CH3CH₂CH₂CH₂(OH)
Draw and give the molecular formula of butan-2-ol
C4H9OH / CH3CH₂CH(OH)CH3
Define a primary alcohol
This is when there is one carbon directly bonded (touching) to the carbon atom that has the -OH group attached.
Name 2 examples of primary alcohols
- Propan-1-il
- Butan-1-ol
Define secondary alcohols
This is when there are two carbons directly bonded to the carbon atom that has the -OH group attached.
Name 2 examples of secondary alcohols
- Propan-2-ol
- Butan-2-ol
Draw 2-methypropan-2-ol
Drawn
Are tertiary alcohols easily oxidised?
No
What is the best known alcohol
Ethanol
Why is ethanol the best known alcohol
As it is found in alcoholic drinks such as beer, wine and spirits.
Name the process in which ethanol is produced
Fermentation
What happens in the fermentation of ethanol
Sugars are converted to ethanol and carbon dioxide by yeast.
What enzyme does yeast contain?
Zymase
Are alcohols toxic?
Yes all are
What are alcohols broken down in the liver to?
An aldehyde
What is it called when alcohols are broken down in the body by the liver to an aldehyde?
Primary metabolite
What can excess consumption of alcohol lead to?
Liver failure and eventually death
What is ethanol used as in a perfume?
A solvent
Name a use for ethanol other than alcoholic beverages and in perfume.
To sterilise
In Brazil what percentage of cars run on ethanol?
20%
What is another name for the ethanol that some cars are run on?
Oxygenate
What does fermentation produce?
CO₂
Give the sample equation for fermentation.
C₆H₁₂0₆ ⇾ 2C₂H₅OH + 2CO₂ (⇾ = ZYMASE)
Why do alcohols have a higher boiling points than alkanes of similar molecular mass?
- Due to the presence of the polar -OH group there is hydrogen bonding between alcohol molecules.
- As a result of this hydrogen bonding more energy is needed to break these bonds.
What are weaker Van der Waals forces, or hydrogen bonding?
Van der Waals
Why are the first four members of the alcohols liquids?
Because of the hydrogen bonding between molecules as the hydrogen bonding holds the molecules together.
What state of matter is the first four alkanes?
Gases
Are the alcohols with smaller carbon chains, soluble or insoluble in water?
Soluble
Why are the alcohols with smaller carbon chain lengths soluble in water?
As there is hydrogen bonding between the alcohol molecules and water molecules.
What happens as the carbon chain length in alcohols increases?
Solubility decreases
Why does solubility decrease as the carbon length in alcohols increases?
As the non-polar carbon chain takes over from the polar -OH group.
Are the larger alcohols soluble or insoluble in water?
Insoluble
Name a non-polar solvent that the larger alcohols are soluble in.
Cyclohexane
What do all alkanes, chloroalkanes and alcohols have?
Tetrahedral carbon
Why do all alkanes, chloroalkanes and alcohols have tetrahedral carbon?
As each carbon in these molecules form four single bonding pairs and no lone pairs.
What does solubility depend on (alcohols)?
The non-polar carbon chains
What do all alcohols form with water?
Hydrogen bonds
What is the oxidising agent used to oxidise primary alcohols to aldehydes and then on to form carboxylic acids?
Acidified sodium dichromate.