Alkanes/enes

Question 1

What is the functional group

Answer 1

Part largely responsible for the molecules chemical properties

Question 2

Homologous series

Answer 2

A series of organic compounds with same functional but differ by CH2

Question 3

Structural isomers

Answer 3

Compunds with same molecular formula but different structural formula, can have same or different fucntional group at different points on chain

Question 4

Homolyctic fission

Answer 4

Each of the covalently bonded atoms take one of the shared electrons, form8ng 2 radicals

Question 5

Heterolytic

Answer 5

1 of the covalently bonded atoms takes both electrons, 1 becomes -ve ion and the other +ve ion

Question 6

Curly arrow

Answer 6

Movement of pair of electrons

Question 7

Substitution

Answer 7

Atom or group of atoms is replaced by a different atom/group

Question 8

Addition

Answer 8

2 reactants join to make 1 product

Question 9

Elimination

Answer 9

Removal of small molecule from a saturated molecule to form unsaturated molecule

Question 10

Hydrogenation

Answer 10

Hydrogen in presence of nickel catalsyt at 150 c. breaks the pi bond, turns alkenes to alkanes

Question 11

Electrophile

Answer 11

Accepts an electrons pair

Question 12

Cracking

Answer 12

Decomposition of alkanes to obtain smaller chain alkanes and alkenes

Question 13

Thermal cracking

Answer 13

Hight temp and pressure for short time

Question 14

Catalytic cracking

Answer 14

Zeolute catalyst present ( eg. SO2, ALO) produce mainly branched alkanes

Question 15

Thermal decomposition

Answer 15

Crude oil separated into different fractions

Question 16

How to test for double bond

Answer 16

Alkene + bromine water = orange to colourless

Question 17

What shape are cis/z isomers

Answer 17

U shaped, so dont pack well

Question 18

Why do trans/e isomers have a lower boiling point that cis isomers

Answer 18

Trans are non polar so only contain london forces whereas cis are polar so contain london forces and permentant dipole-dipole interactions.

Question 19

Why do trans isomers have a higher melting point than cis

Answer 19

Cis are U shaped so cant pack together well but trans can so the london forces in trans are closer togther therefore stronger

Question 20

Sigma bonds

Answer 20

Are the overlapping of 2 S orbitals. Atoms can rotate freely around them

Question 21

Pi bond

Answer 21

Overlapping of 2 P orbitals. Prevents rotation

Question 22

3 steps of free radical substitution

Answer 22

Initiation
Propogation
Termination

Question 23

Electrophillic addition

Answer 23

The double bond in alkene is an area of high electron density due to pi bond, so electrophiles are attracted to this area of high electrom denstity. The pi bond breaks due to it being attracted to a dipole on the reactant and then a carbocation is formed which will also atrract another molecule

Question 24

How to make alcohol

Answer 24

Alkene + steam = alcohol

Conditionsa include acid catalyst H3PO4 ( phosphoric acid)