4.1.1 Basic concepts & 4.1.2 Alkanes

Question 1

Hydrocarbon

Answer 1

contains H and C only

Question 2

staturated

Answer 2

contains only C-C single bonds

Question 3

unsaturated

Answer 3

contains at least one c=c double or triple bond

Question 4

Aliphatic

Answer 4

contains C atoms joined in straight or branched chains - not a benzene ring

Question 5

Alcytic

Answer 5

aliphatic molecule that contains C atoms joined in a ring but not a benzene ring

Question 6

Aromatic

Answer 6

contains at least one benzene ring

Question 7

Alkanes general formulae

Answer 7

CnH2n+2

Question 8

how to draw skeletal formualae

Answer 8

dont draw carbons or H

Question 9

ethane structural formulae

Answer 9

CH3CH3

Question 10

how is a sigma bond formed

Answer 10

by overlapping orbitals between bonding atoms

Question 11

can sigma bonds rotate

Answer 11

yes they can freely rotate

Question 12

how is a Pi bond formed

Answer 12

formed by overlapping P orbitals above and below bonded atom

Question 13

can Pi bonds rotate

Answer 13

No

Question 14

what bonds make a double bond

Answer 14

Pi and sigma

Question 15

what bond makes a single bond

Answer 15

Sigma

Question 16

Bond fission definition

Answer 16

breaking covalent bonds

Question 17

Homolytic fission definition

Answer 17

where covalent bond breaks and one of the bonding electrons moves to each atom forming 2 radicals

Question 18

radical

Answer 18

species with at least one unpaired electron

Question 19

a fish

Answer 19

hook arrow representing movement of 1 electron

Question 20

Heterolytic fission

Answer 20

covalent bond breaks and both bonding electrons go to one of the atoms forming an anion and a cation

Question 21

what does a curly arrow represent

Answer 21

movement of a pair of electrons when a covalent bond is broken or formed

Question 22

mechanism definition

Answer 22

shows which covalent bonds are being broken and made

Question 23

3 types of reactions

Answer 23

substitution
addition
elimination

Question 24

substitution reaction

Answer 24

1 element is replaced by another in a molecule

Question 25

addition reaction

Answer 25

where theres fewer products than reactants

Question 26

elimination reaction

Answer 26

where theres one more product than reactants

Question 27

what state are the first 4 alkanes

Answer 27

gases

Question 28

what happens to the boiling point as the alkane gets bigger and why

Answer 28

increases as number of carbons increases due to there being more IMF that need more energy to overcome

Question 29

strongest IMF in an alkane

Answer 29

London forces

Question 30

do larger molecules have stronger or weaker london forces and why

Answer 30

stronger as they have more electrons

Question 31

why do branched alkanes have lower melting points than straight chained alkanes

Answer 31

straight chained have more points of contact so there’s more london forces so more energy is required to overcome the IMF

Question 32

what does complete combustion of an alkane form

Answer 32

carbon dioxide and water

Question 33

what does incomplete combustion of alkane form

Answer 33

Carbon monoxide and water

Question 34

Free Radical substitution steps

Answer 34

initiation
propagation
termination

Question 35

chlorination of methane initiation step

Answer 35

Cl2 -> 2Cl*

Question 36

chlorination of methane propagation step

Answer 36

Cl* + CH4 -> CH3* + HCl
CH3* + Cl2 -> CH3Cl + Cl*

Question 37

what is the termination

Answer 37

add the radicals together to make Cl2
CH3Cl
C2H6

Question 38

Limitations of free radical substitution

Answer 38

further substitutions can occur creating unwanted products from the radicals