Alkanes And Alkenes Test

Question 1

What’s a functional group?

Answer 1

An atom or group of atoms that give a molecule its characteristic physical/ chemical properties.

Question 2

What is a homologous series?

Answer 2

Have the same general formula and same functional group; differ by -CH2- unit.

Question 3

What’s a formula?

Answer 3

A way of expressing the ratio of elements in a compound

Question 4

General formula

Answer 4

Algebraic eg CnH2n

Question 5

Empirical formula

Answer 5

Smallest whole number ratio of elements in a substance

Question 6

Molecular formula

Answer 6

Actual number of each element in a covalent molecule

Question 7

Displayed formula

Answer 7

Shows all the bonds

Question 8

Structural formula

Answer 8

Shows the functional groups

Question 9

Skeletal formula

Answer 9

Shows only bonds plus non-carbons or hydrogens (Heterolytic-atoms)

Question 10

Addition reaction

Answer 10

Joining two or more molecules together

Question 11

Polymerisation reaction

Answer 11

Joining lots of small simple molecules together

Question 12

Elimination reaction

Answer 12

Small group of atoms break away from a larger molecule

Question 13

Substitution reaction

Answer 13

One species is replaced by another

Question 14

Species

Answer 14

Atom, ion or molecule

Question 15

Hydrolysis reaction

Answer 15

Splitting a molecule into two new molecules using H+ and OH- ions in water

Question 16

Oxidation reaction

Answer 16

Electrons lost by a species

Question 17

Reduction reaction

Answer 17

A species gains electrons

Question 18

Free radical substitution steps

Answer 18

1. Initiation - formation of a radical from UV light
2. Propagation A and B - using a radical to make a radical
3. Termination - two radicals react

Question 19

Thermal cracking of petroleum (crude oil)

Answer 19

High temperature (up to 1000 deg C)
High pressure (up to 70 atm)
Produces lots of alkenes

Question 20

Catalytic cracking of petroleum (crude oil)

Answer 20

Zeolite catalyst
Slight pressure
High temperature (up to 450 deg C)
Produces aromatic hydrocarbons and motor fuels

Question 21

Reforming

Answer 21

Turning straight chain alkanes into branched-chain and aromatic
Reduces knocking

Question 22

Combustion of alkanes

Answer 22

Into CO2 and H2O

Question 23

Incomplete combustion of alkanes

Answer 23

Carbon monoxide, water, soot

Question 24

Combusting fossil fuels

Answer 24

Releases:
Greenhouse gases
Carbon monoxide
Carbon particulates
Sulphur oxides
NOxes

Question 25

Reducing environmental effects of combusting alkanes

Answer 25

Catalytic converters turn nitrogen monoxide and carbon monoxide into nitrogen and CO2

Question 26

Alkenes

Answer 26

Unsaturated
Functional group C=C
General formula CnH2n

Question 27

Why do alkenes have geometrical isomerism (stereoisomerism)?

Answer 27

The molecule cannot rotate around the double bond because this would break the pi bond

Question 28

Stereoisomerism

Answer 28

ONLY OCCURS when BOTH CARBONS have TWO DIFFERENT substituents attached to them
E (opposite)/ Z (zame zide)
Cis-trans IF both carbons have a hydrogen attached

Question 29

Naming stereoisomers

Answer 29

Same as normal, number from the double bond, determine isomerism by high priority groups

Question 30

Electrophilic addition

Answer 30

CURLY ARROWS: DO THEM RIGHT
Major and minor products from different transient intermediates

Question 31

Transient intermediates

Answer 31

Exist for a short time
Different stabilities- 1, 2, 3, where higher number is more stable due to inductive donating electron effect
Carbocations in electrophilic addition

Question 32

Disposing of polymers

Answer 32

Landfill: it’s in landfill. We’re running out
Recycle: increases use for carbon footprint. Downcycle
Incinerate: energy. Releases bad stuff
Crack: turn into fuels. Lots of bad waste products, energy intensive