Studied by 8 people
carbon
the chemistry of carbon is much more extensive than that of any other element with many compounds of carbon. the macromolecules that build up life are made of carbon
4 valence electrons, abundance and high bonding capacity
difference between O2 and O3
O2 is stronger than O3 and O2 absorbs more UV
Why does benzene undergo substitution more readily than addition?
resonance makes C_C bonds too strong to break easily
catenation
the fact that carbon atoms can join together to form chains and rings
fractional distillation
components in a chemical mixture are separated using their different boiling points.
Alkanes
a family of hydrocarbons
reactivity of alkanes, alkenes and alkynes
Alkanes are the least reactive, alkene is more reactive, and alkyne is the most reactive
Carbon always makes how many bonds?
4
How does hydrocarbon molecular size effect its state
larger hydrocarbons have more LDF making it more polarizable = Higher Melting/boiling points (more bonds need to be broken to boil)
Isomers
Different compounds that have the same molecular formula
Functional Groups
Atom/group of atoms that give the molecule its chemical properties. They are the reactive part of the compound
Homologous Series
A series of compounds that have the same functional group - Each member differs by a unit of CH2
How does melting point change when a CH2 group is added?
melting/boiling point increases as it now has more bonds to break through
Aliphatic
Structures of straight/ branched chains/ rings of carbon atoms
Alkanes
Alkenes
Alkynes
Cyclic
Alkanes
Carbons bonded by single bonds (sigma bonds) making them fully saturated hydrocarbons. very stable. CnHn+2
Alkenes
A molecule that has at least one double bond (pi bond) between two carbon atoms, resulting in an unsaturated hydrocarbon (not the maximum number of hydrogens are bonded to the carbon atom). Unstable/reactive. CnH2n
Alkynes
A molecule that contains at least one triple bond between carbon atoms, wrestling in an unsaturated hydrocarbon. CnH2n-2
Aromatic
Structures based on that of benzene. Essentially the functional groups are the benzenes
Benzene
A ring of 6 carbon atoms that are bonded to one another with double and single bonds with a resonance structure C6H6
-the electron in the double bond are shared equally among all the carbons
Very stable molecule because of its resonance
“Pi electrons are delocalized in its arrangement “
Geometric (cis-trans) Isomers
When the alkyl groups are found on the same side of the carbon then it’s cis and if it’s on opposite sides than it’s trans
Benezene’s with Halogen substituent Groups
just named as “halogen prefix”benzene
Benzoic acid
benzene with a carboxyl (COOH) substituent group
Phenol
Benzene with a hydroxyl (OH) substituent group
Aniline
Benzene with an ammonia substituent group
Toluene
Benzene with a methyl (CH2) substituent group
Benzene as a substituent
Sometimes in hydrocarbon chains benzene is treated as a substituent and it is simply named using “phenyl”
Alcohols
Functional group: hydroxyl
Naming: anol
Example: Ethanol
General Formula: CnH2n+1OH
Properties of Alcohols
More polar than hydrocarbons - as hydrocarbon chain gets longer it becomes more non-polar Form hydrogens bonds because of the hydroxyl group Higher melting/boiling points since it has hydrogen bonds
Hydroxyl Group
an OH group (hydroxide)
Types of alcohols
Primary Alcohol 1 o : bonded to 1 carbon alkyl Secondary Alcohol 2o: bonded to 2 carbon alkyl Tertiary Alcohol 3 o : bonded to 3 carbon alkyl
polyalcohol
Includes more than one hydroxyl group
Aldehydes
Functional group: aldehydes (carbonyl)
Suffix: anal
Example: Ethanal
General formula: RCHO
Aldehyde Properties
Lower melting/ boiling points than alcohols since they don’t have the OH group for hydrogen bonding Also are less soluble in water than alcohols However, C=O bond is polar so they are more soluble and have higher boiling and melting points than hydrocarbon
Ketones
Functional Group: Carbonyl
Suffix: anone
Example: Propanone
General formula: RC(O)R'
Properties of Ketones
Lower melting/boiling points and less soluble in water than alcohols However, C=O bond is polar so they are more soluble and have higher boiling and melting points than hydrocarbon
Ether
R-O-R If it’s not the priority it’s represented with “oxy” always as a prefix
Ether properties
A polar C-O bond, however can’t form hydrogen bonds More soluble and higher melting/boiling points than hydrocarbons Less polar and lower melting/boiling points than alcohols
Esters
R-C(=O)(-O)-R’ - Made with a carboxylic like group in the middle however the hydrogen atom is replaced with another carbon chain Main chain suffix end is “oate”
Ester Properties
Since it has no hydrogen bonding it is less polar than alcohols and carboxylic acids but it is still more polar than ethers and hydrocarbons More soluble and have higher mp/bp point than ethers and hydrocarbons but less soluble and lower mp/bp than alcohols and carboxylic acids (as an aqueous solution)
Amines
R-C-N-R’ - A carbon group bonded to a nitrogen (the nitrogen group can be bonded to up to two hydrocarbon chains or 2 hydrogens) - Functional group is NH2 Main chain suffix end is “amine”
Amines properties
SMALL amines are soluble in water as N-C bonds are polar Higher mp/bp than hydrocarbons but because it’s less polar than O-C groups it is lower than alcohols
Types of amines:
Primary Amine 1 o : 1 hydrocarbon chain Secondary Amine 2 o : 2 hydrocarbon chains Tertiary Amine 3 o : 3 hydrocarbon chains
Amides
R-C(=O)(-N)-R’ - Similar to an ester but has an N instead of a single bonded O - Functional group is CONH2 Main chain suffix end is “amide”
Amide Properties
Smaller amides are water soluble as C=O is polar and forms hydrogen bonds with N Higher mp/bp than ketones/aldehydes but a lower polarity than carboxylic acids When maximum number of hydrogens are bonded to the amide it has a higher boiling point because it now has more hydrogen bond
Free radical substitution - 3 steps
Initiation Propagation Termination
Free Radical Substitution Step 1: Initiation
The making of a free radical (1 reaction) Splits the electron equally, both atoms get one of the previously shared electrons - Forming the free radicals with the divided atoms
Heterolytic Fission
Splits the electron unevenly, one atom gets all the previously shared electrons
Homolytic Fission
Splits the electron equally, both atoms get one of the previously shared electrons Written as X•
Free Radical Substitution Step 2: Propagation
The radical swapping around until the compound and the radical form another compound (2 reactions) Radical takes hydrogen from the hydrocarbon forming a free radical hydrocarbon Then the free radical hydrocarbon reacts with an element (that was originally the free radical from the initial step) and forms a compound with it and there is now an extra free radical of the original free radical
Free Radical Substitution Step 3: Termination
Shows all the radicals combining to form their respective compounds (3 reactions)
Overall reaction
the radicals original compound + the hydrocarbon → (catalyst of UV) hydrocarbon with the element radical + the hydrogen and the element radical
Bond Order
NHumber of chemical bonds between a pair of atoms - represents it’s stability Number of covalent bonds divided by the number of atoms involved in the compound
Relationship between bond order and bond length
Bond order and bond length are inversely proportional to each other: as bond order increases bond length decreases bond length which tells us how strong it is: Smaller bond lengths means it is a stronger bond and vice-versa
Catalysis of O2 in Ozone depletion
O 2 divides into two oxygen free radicals Bond order of 2 → longer bond length → Weaker → less energy needed to break Only needs UV-C
Catalysis of O3 in Ozone depletion
O 3 divides into 1 oxygen free radical and then an oxygen compound Bond order of 1.5 -> Shorter bond length → stronger → more energy needed to break Needs UV-B
Chlorofluorocarbons
Stable compounds that break down when it absorbs UV radiation → forms free radicals destroys the ozone molecules when it is broken down by the UV light
What can prevent the destruction of the ozone?
These reactions can stop when the free radicals of NOx and CFCs collide together and form their own compound
Polymers
Molecules with many repeating identical parts Made up of monomers Unreactive
Natural Polymers made of
DNA, Proteins, oils, fats etc
Monomers
Building blocks of polymers Extremely reactive
Benefits of polymers
Cheaper to produce, and are chemical and biological UNREACTIVE Have many properties
Polymer Formation: Addition Reactions
Involving an alkene monomer - Producing a long alkane chain Double bonds break and then a bond that is adjacent to the monomers form on BOTH sides of the original monomer
Different o=polymers made from addition reactions
Polyethylene (made from a chain of ethylene) ← Ethene Polypropylene (made from a chain of propylene) ← Propene Polyvinylchloride Polystyrene (made from a chain styrene) ← Phenylethene Teflon
Polymer formation: Condensation Reactions
Involves the condensation of one or two monomers with functional groups Producing amides and esters and water
Condensation Reactions
, a condensation reaction is a type of chemical reaction in which two molecules are combined to form a single molecule, usually with the loss of a small molecule such as water. If water is lost, the reaction is also known as a dehydration synthesis
Alcohol
Functional group: hydroxyl Naming: anol Example: Ethanol General Formula: CnH2n+1OH
Ether
Functional group: ether Suffix: oxy alkane Example: Methoxy Propane General formula: ROR'
Carboxylic acid
Functional group: Carboxylic acid Suffix: anoic acid. Example: Ethanoic Acid General formula: RCOOH. OH groups make these even more polar than other functional groups, so very soluble in water very high melting/boiling points
Ester
Functional group: Ester Suffix: alkyl anoate Example: Methyl Propanoate General formula: RCOOR'
Amine
Functional group: Amine Suffix: anamine Example: Ethanamine General Formula: RNH2
Amide
Functional Group: Amine Suffix: anamide Example: Ethanamide General Formula: RC(O)NH2
alkene/alkyne colour change in bromine water
orange→ colourless
alkane colour change in bromine water
no colour change
Note 
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