Organic Compounds Flashcards
What are the 4 chloroalkanes?
1) Chloromethane
2) Dichloromethane
3) Trichloromethane
4) Tetrachloromethane
What were chloroalkanes originally used for?
Anaesthetic (chloroform)
What are modern uses of chloroalkanes?
Sovents: removing oil and grease and dry cleaning
What are the properties of chloroalkanes?
Non-polar
Dissolve in non-polar solvents (cyclohexane)
Low boiling points
What is a functional group?
Functional group is an atom or a group of atoms which are responsible for the characteristics of a series of organic compounds
What is the functional group of alcohols?
OH
What shape are alcohols?
Tetrahedral
What is a primary alcohol?
One carbon attached to the carbon attached to the OH.
What is a secondary alcohol?
2 carbons attached to the carbon attached to the OH.
What is a tertiary alcohol?
3 carbons attached to the carbon attached to the OH.
What letter is used to represent an alkyl group?
R
What are uses of ethanol?
Perfume, lotion and dyes
Whats the functional group of aldehydes and ketones?
C=0 (CHO)
What the structural difference between aldehydes and ketones?
Aldehydes:C=0 at end of chain
Ketones:C=0 middle of chain
What are the functions of some aldehydes and ketones?
Propanone: solvent in paints, varnishes, nail polish
Methanal: preserving/embalming, polymer adhesives
What are the four carboxylic acids?
1) Methanoic
2) Ethanoic
3) Propanoic
4) Butanoic
What are some properties of carboxylic acids?
Colourless with sharp distinctive smells
Higher boiling points than alcohols of same mass
4 carbons are soluble
>4 carbons are less polar and less soluble
What are some uses/occurrences of carboxylic acids?
1) Methanoic acid in ant stings
2) Ethanoic acid is vinegar. It can also be used to manufacture cellulose acetate for varnish and photographic film.
3) propanoic acid- salts for food preservation
What is the functional group for carboxylic acids?
COOH
What is the functional group for carboxylic acids?
COOH
What is the boiling point of ethanal?
21C
Common uses for esters?
Fragrances, essential oils and pheromones.
What is the functional group of esters?
COO
What is the general formula for esters?
RCOOR’
How are esters made?
Condensing acids with alcohols
What is a substitution reaction?
A chemical reaction in which an atom or a group of atoms in a molecule are replaced by another atom or group of atoms.
What is a free radical?
Any species with a free, unpaired electron.
What is a chain reaction?
Reaction that continues on and on because a product from one step of the reaction is the reactant for another step.
What do you get when you add chlorine to methane?
Chloromethane and hydrogen chloride.
Features of free radical reactions?
Often explosive and difficult to control due to extremely reactive nature of radicals.
What are the 3 steps in a substitution reaction?
Initiation, propagation and termination.
What happens in initiation?
Diatomic molecule chlorine undergoes homolysis when exposed to UV light.
What happens in propagation?
Chlorine radical attaches to the methane to from hydrogen chloride and a methyl radical.
What happens in termination?
Number of reaction occur to stop the chain reaction. All involve free radicals combining with each other to from molecules.
What kind of reaction involves UV light?
Photochemical reaction.
What is hydrolysis?
Chemical decomposition of a substance by water, the water itself also being decomposed.
What is a polymer?
Very large molecule made up of many identical repeating units called monomers.
What are halogenalkanes used in?
Fire extinguishers, refrigerants, pharmaceuticals and propellants.
What is an addition reaction?
Reaction in which 2 substances react together to form a single substance.
What is an elimination reaction?
Reaction in which a small molecule is removed from a larger molecule to leave a double bond in the larger molecule.
How does an ionic addition reaction occur?
Step 1: polarisation- high conc. of negative charges. (Element) gets closer and becomes polarised.
Step 2:- induced polarisation becomes so great the molecule splits. 2 electrons on 1 atom is heterolytic fission.
Step 3: carbonium ion formation- (element) needs stability so attacks (compound). Forms covalent bond to a carbon. Other carbon has (+) charge.
Step 4: Ionic addition- carbonium ion attacked by (element with (-) charge).
What evidence proves free radical mechanism?
- UV light of sufficient high energy is needed to break the bonds in chlorine moelcule, forming chlorine atoms. When a mixture of alkane and chlorine irradiated with UV light for a short period a chain reaction occurs.
- Formation of ethane is evidence for termination
- Reactions speeded up by adding known sources of free radical ie tetraethyllead
