chemistry/ organic compounds

type of bond

low/high melting pt in organic compounds?

covalent bond

low melting, boiling pt

can undergo combustion

what is a hydrocarbon

an organic compound consisting only of hydrogen and carbon atoms without any functional groups.

what reduces and what increases the oxidation number?

H reduces (-1)

every heteroatom (N,O,S…) increases

C leaves it unaltered

what kind of bond do the molecules in alkanes form (or any single bond)?

o (sigma) bond

what kind of arrangment do sp3 orbitals have?

tetrahedral

what kind of p atomic orbitals form pi molecular orbitals to form double (sp2) or triple (sp) bonds?

non-hybridized p atomic orbitals

why do organic compounds enter reactions?

single bonds are saturated double and triple bonds are unsaturated so the goal is to have as many single bonds to obtain the most saturated compounds.

what defines the properties of the organic molecule and adds reacticity?

functional groups

HYRDOCARBONS DONT MIX WITH WATER

just dont forget!! they are also composed of apolar bonds and they can be linear, branched or cyclic

why is the 3D structure of molecules important?

because it modulates their chemical properties and determines their biological function

what is conformation

the shapes that molecules can adopt due to rotation about bonds (different conformation different properties)

what is a conformational isomer

same molecule different arrangment of the ch3 groups

what is steric hindrance

bic molecules blocking the reaction

explain this

why does cyclohexane not have a planar structure?

-the sp3 interactions prevent it

-to obtain a planar structure the angles need to be 120 degrees which is much greater than the angle between hybrid orbitals

the required distortion would lead to a very high energy and thys unstable molecule

what is the chair conformation

four atoms on a plane one above and one below

what are the orientations of a cyclic structure

axial (higher energy) or equatorial (lower energy) (both are chair cyclohexane forms)

which cylic structure is preferred

equatorial bc it has lower energy

what is the way to convert one cylic structure to another called?

chair flip

what can we replace a hydrogen in an alkane with?

a halogen or an alkyl chain

to create a structural isomer how many carbon atoms is the alkane supposed to have (minimum)

4+

name these isomers

isopentane and neopentane

do an organic compound and it’s isomer have different chemical properties?

yes

which alkanes are used as heatinf fuels

methanes and butanes

which alkanes are volatile liquids, fuels

pentane and octane

if we get a longer alkane chain what else increases

they become waxy solids and their boiling/ melting point increase

why does the boiling/ melting point increase when the length of the C chain increase

because of the dispersion forces. the bond between c atoms are hard to break

when branching increases what else also increase

melting/ boiling point

what kind of alkanes have the highest melting/ boiling point

cyclic alkanes

why do branched alkanes have a lower boiling point?

the 3D arrangment of the substituents makes intermolecular packing less easy to achieve

why are alkanes so little reactive

the c-c bonds are very strong and difficult to break

what is added for the combustion of alkane

alkane + 02 —> CO2 + H2O + energy

what does the reaction of an alkane and a halogen create

a haloalkane

what is a nucleophilic substitution

a chemical reaction where an electron rich species replace a functional group on an electron deficient molecule

what is a nucleophile

a molecule/ ion that has at least one electron pair in a non-bonding orbital (a nucleophile always have negative charge)

what is a carbocation

a positively charged ion with a positive charge on a carbon atom

what is a sn1 reaction

formation of an intermediate carbocation with possible arrangments

what is a sn2 reaction

leaving group leaves as the nucleophile approaches. inversion of configuration of the carbon atom

why are alkanes and alkynes unsaturated hydrocarbons

because they dont contain the maximum amount of hydrogen atoms

what is a reduction reaction

reaction with a hydrogen gas to increase the number of hydrogen atoms and become alkanes

in a reduction reaction does the oxidation number decrease

yes

alkenes bond and arrangment

hybridized sp2 bond and trigonal planar arrangment

alkynes bond and arrangment

hybridized sp bond and linear comformation

do alkanes, alkenes, alkyns have free rotation

alkanes have free rotation but alkenes and alkynes dont

what causes a cis-trans isomerism

the presence of a double or triple bond that restricts the bond rotation within a molecule

which one is a z isomer and which one is an e isomer and why

z isomer/ e isomer because of the atomic numbers we understand which is cis and which is trans

what is an electrophile

substances deficient in electrons

what is an electrophilic addition

electrons form a bond using the pi electrons of the double bond forming a carbocation. the hybridization of the atoms changes to sp3. then a nucleophile can make a bond with the carbocation. as a result the souble bond is now single and we added two dif groups to the carbon atoms

in this reaction what is the role of a proton (it means H+ i guess)

protons are not reactants they are catalysts

if the addition occurs to an assymetric alkene which c atom does the electrophile attack

the less substituted one to yield the most stable carbocation (tertiary>secondary>primary) (less c atom attached more chance of the electrophile attacking to c)

what do polymerization reactions require?

high temperature

a catalyst

high pressure

going from down to up does the stability increase or decrease

it increases (more c-c bonds more stability)

what is the bond lenght in aromatic compounds and c single and double bond lenghts?

140 pm / 154 pm / 134 pm

if benzene acts as a substituent in a compound what does it’s name become

phenyl group (phenol is a different things dont confuse)

what are their names

1,2 diclorobenzene

1,3 diclorobenzene

1,4 diclorobenzene

what are their other names

o-diclorobenzene

m-diclorobenzene

p-diclorobenzene

difference berween electrophile and nucleophile

electrophile has a + charge nucleophile has a - charge

name these

ok

what are some benzene based compounds

aspirin, acetaminophen, ibuprofen, phenylalanine (amino acid), vanillin

what is electrophilic substitution

first, addition of electrophile, breaking the aromatic system

then, exit of a leaving group to obtain a substituted aromatic compound