Organic 1 General And Alkanes

Question 1

Sigma bonds

Answer 1

Two orbitals overlap in a straight line
Highest possible electron density between the two nuclei
High electrostatic attraction, high bond enthalpy

Question 2

Pi bond

Answer 2

Two lobes of two orbitals overlap sideways
Electron density spread out above and below the two nuclei
Relatively low bond enthalpy

Question 3

C=C

Answer 3

Trigonal planar 120
Atoms can’t rotate around them (restricted rotation)

Question 4

Stereoisomer

Answer 4

Two double bonded carbon atoms each have two different atoms or grouped attached to them

Question 5

E isomer

Answer 5

Highest priority groups split across c=c

Question 6

Trans isomer

Answer 6

Same groups split

Question 7

Z isomer

Answer 7

Highest priority groups on same side of c=c

Question 8

Cis isomer

Answer 8

Same group on same side

Question 9

Reforming

Answer 9

Processing of straight chain hydrocarbons into branched chain alkanes and cyclic hydrocarbons for efficient combustion

Question 10

Thermal cracking

Answer 10

Produces lots of alkenes
Homolytic fission occurs
Also produces smaller alkanes and some H2

Question 11

Catalytic cracking

Answer 11

Silicon dioxide and aluminium oxide catalyst (zeolite)
Heterolytic fission— positive alkyl group /carbocation
Forms mostly smaller alkanes

Question 12

Solution to sulfur impurities causing acid rain

Answer 12

Desulfurisation
Using CaO or CaCO3

Question 13

Solution to NO, CO and unburned alkanes

Answer 13

Catalytic converters

Question 14

Catalytic converters

Answer 14

Platinum catalyst
Reacts them together to produce less harmful products
Honeycomb structure made of ceramic for high surface area
Tend to produce N2 (inert), CO2 and H2O

Question 15

Biodiesel

Answer 15

Refining renewable fats and oils

Question 16

Bio ethanol

Answer 16

Fermentation of sugar from crops

Question 17

Biogas

Answer 17

Break down of organic waste matter

Question 18

Limitations of free radical substitution

Answer 18

Mixture of products (reduce by using excess of the alkane)
Further substitution reactions (H continue being substituted)
Mixture of structural isomers (substitution can occur at any place on the chain)

Question 19

Homologous series

Answer 19

Group of organic compounds that have the same general formula and functional group, consecutive members differ by CH2, have similar chemical properties and show a gradual variation in physical properties

Question 20

Functional group

Answer 20

Group of atoms in a molecule responsible for the characteristic reactions of the compound

Question 21

Empirical formula

Answer 21

Simplest whole number ratio of atoms of each element in a compound

Question 22

C10H22+31NO=10CO2+151/2N2+11H20 catalytic converter
Give reason why this reaction might not proceed according for the equation

Answer 22

Oxygen is present and so intermediate compounds/ C10H22 might react with oxygen
NO might react with CO/or oxygen to from NOx

Question 23

Cracking

Answer 23

Process of breaking up larger, less useful hydrocarbons into smaller more useful ones

Question 24

Formation of nitrogen oxides in engines

Answer 24

High pressure and heat cause nitrogen and oxygen in air to react together
Nitrogen oxides dissolve in atmospheric moisture to form nitric acid

Question 25

Free radical substitution propagation

Answer 25

Half arrow from chlorine radical to hydrogen Half arrow showing homolytic fission of C-H bond pointing to C Forms free radical and HCl Free radical reacts with Cl2 where half arrow shows homolytic fission of Cl-Cl and arrow from free radical to other Cl Forms haloalkane and chlorine free radical

Question 26

Branching effect in boiling temp

Answer 26

Lower Fewer/weaker London forces Due to less surface area / points of contact