Organic Chemistry

Question 1

what is the definition of homologous series?

Answer 1

family of compounds containing the same functional group but with each successive member differing by a -CH2 group

Question 2

what is the definition of hydrocarbon?

Answer 2

compound containing only carbon and hydrogen atoms

Question 3

what is the definition of saturated hydrocarbons?

Answer 3

compounds containing only C-C bonds

Question 4

what is the definition of unsaturated hydrocarbons?

Answer 4

compounds containing at least one multiple bond between carbon atoms

Question 5

what is the definition of functional group?

Answer 5

atom/group responsible for the characteristic reactions of the compound

Question 6

why is alkane/alkyl not a functional group?

Answer 6

• very unreactive
• large bond enthalpies
• non-polar/low polarity

Question 7

what is an aliphatic compound?

Answer 7

compounds of C and H joined together in straight/branched chains or non-aromatic rings

Question 8

what is an alicyclic compound?

Answer 8

compounds arranged in non-aromatic rings, with or without side chains

Question 9

what is an aromatic compound?

Answer 9

compounds that contain a benzene ring

Question 10

what is structural isomerism?

Answer 10

molecules with the same molecular formula but different structural formula

Question 11

what are the different types of structural isomers?

Answer 11

• chain length
• position isomers
• functional groups isomers

Question 12

what is homolytic fission?

Answer 12

the breaking of a covalent bond where an electron from the bonding pair goes to each atom to form two radicals?

Question 13

how are two radicals formed?

Answer 13

homolytic fission

Question 14

what is heterolytic fission?

Answer 14

the breaking of a covalent bond where both electrons from the bonding pair goes to one atom forming two ions

Question 15

why do alkanes have low reactivity?

Answer 15

have high bond enthalpy and low polarity of sigma bonds

Question 16

what is complete combustion?

Answer 16

combustion with sufficient oxygen

Question 17

what is incomplete combustion?

Answer 17

combustion with insufficient oxygen

Question 18

what are the products of complete combustion?

Answer 18

carbon dioxide (CO2) and water (H2O)

Question 19

what are the conditions of free radical substitutuion?

Answer 19

• UV radiation
• excess alkane

Question 20

whats the general formula for an alkane?

Answer 20

CnH2n+2

Question 21

whats the general formula for an alkene?

Answer 21

CnH2n

Question 22

what kind of IMF is between alkanes/alkenes?

Answer 22

induced dipole-dipole

Question 23

what kind of IMF is between alcohol molecules?

Answer 23

hydrogen bonding

Question 24

why do alcohols have higher bp than alkanes/alkenes?

Answer 24

hydrogen bonding is stronger than IDD forces, so require more energy to overcome

Question 25

what is hydrogenation?

Answer 25

when an alkene reacts with hydrogen to form an alkane

Question 26

what is the reagent of hydrogenation?

Answer 26

H2

Question 27

what are the conditions of hydrogenation?

Answer 27

150 degrees Ni catalyst

Question 28

what is hydration?

Answer 28

when an alkene reacts with water to form two compounds

Question 29

what are the reagents of hydration?

Answer 29

H2O(g) / steam

Question 30

what are the conditions of hydration?

Answer 30

high temp and pressure any acid catalyst

Question 31

what are the reagents for halogenation?

Answer 31

- halogen - halogen halide

Question 32

what is a sigma bond?

Answer 32

single, direct, head-on overlap of p-orbitals between bonding atoms

Question 33

what is the shape of alkanes?

Answer 33

tetrahedral

Question 34

what is the bond angle of alkanes?

Answer 34

109.5 degrees

Question 35

what are the three steps of free radical substitution?

Answer 35

1) initiation 2) propagation 3) termination

Question 36

what are disadvantages of FRS?

Answer 36

- low % yield of desired haloalkane - separation by fractional distillation, which is expensive - have to use excess alkane to avoid further substitution

Question 37

what are the limitations of FRS?

Answer 37

- further substitution - further side reactions - structural isomers can form

Question 38

how do we explain boiling point trends in alkanes (chain length)?

Answer 38

- as chain length increases - bp inc - surface contact inc - more IDD forces - more energy required to overcome IMF

Question 39

how do we explain boiling point trend in alkanes (branching)?

Answer 39

- as branching inc - bp dec - surface contact dec - less IDD forces - less energy required to overcome IMF

Question 40

what is a pi bond?

Answer 40

sideways, double overlap of p-orbitals above and below double c bond

Question 41

what is the shape of an alkene (double bond)?

Answer 41

trigonal planer

Question 42

what is the angle of an alkene (double bond)?

Answer 42

120 degrees

Question 43

what is a structural isomer?

Answer 43

molecules with the same molecular formula but different structural formula

Question 44

what is a stereoisomer?

Answer 44

molecules with the same structural formula but different atom arrangement in space

Question 45

what is the criteria for E/Z isomers?

Answer 45

- double carbon bond - must have two different groups attached to each double carbon

Question 46

what is the criteria for cis/trans isomers?

Answer 46

- double carbon bond - must have 2 different groups attached to each double carbon - two groups must be identical from different carbons

Question 47

what is a Z isomer?

Answer 47

when highest priority groups are on the same side

Question 48

what is an E isomer?

Answer 48

when the highest priority groups are on opposite sides

Question 49

how do you determine the highest priority group?

Answer 49

atomic group

Question 50

what are the problems of disposal of polymers?

Answer 50

- non-biodegradable - burning produces toxic gases

Question 51

how do we minimise environmental damage of polymers?

Answer 51

biodegradable/photodegradable polymers

Question 52

what is an electrophile?

Answer 52

an electron acceptor

Question 53

where do curly arrows start and end?

Answer 53

from an electron rich region to an electron poor region

Question 54

what is the chemical test for an alkene functional group?

Answer 54

1) add Br2 (l) 2) if alkene present: orange -> colourless