(YELLOW) alkanes

Question 1

what is the definition of hydrocarbon

Answer 1

Hydrocarbons compounds containing carbon and hydrogen only.

Question 2

what is the name give to carbon that can form chains and rings called

Answer 2

catenation

Question 3

what is the electronic configouration of carbon

Answer 3

1s2 2s2 2p2

Question 4

why does silicon not replace carbon in organic matter

Answer 4

silicon is just too big

Question 5

what is homologous series

Answer 5

Homologous series A family of compounds with the same functional group, which differ in formula by CH2 from the next member.

Question 6

give examples of homologous series

Answer 6

alkene , alkane , carboxilic acid . alcohols , alkalines , esters , amino acids

Question 7

what is a functional group

Answer 7

Functional Group
the atom or group of atoms responsible for the chemical behaviour of the molecule

Question 8

what is the definition of empirical formula :

Answer 8

Empirical formula shows
The simplest whole number ratio of atoms present in the molecule.
e.g. C5H12

Question 9

what is the definition of Molecular formula

Answer 9

Number of each kind of atom present in the molecule
e.g. C5H12

Question 10

what is the definition of Structural formula

Answer 10

Structural formula shows
the functional groups present and how the atoms are linked
e.g. CH3CH2CH2CH2CH3

Question 11

what is the definition of Displayed formula

Answer 11

Displayed formula shows
all the covalent bonds single bonds as a line, double bonds as C=C and triple bonds as C≡C. All H atoms must be shown.

Question 12

what is the definition of Skeletal formula

Answer 12

Skeletal formula
Omit C atoms and H atoms, - is a single bond, = a double bond and ≡ is a triple bond
if there is another atom present then it is shown.

Question 13

what are the names given to chain lengthens from 1 to 10

Answer 13

1 methane
2 ethane
3 propane
4 butane
5 pentane
6 hexane
7 heptane
8 octane
9 nonane
10 decane

Question 14

what are the four rules of naming compounds

Answer 14

If there are several branches of different lengths they are put in alphabetical order. i.e. ‘ethyl’ before ‘methyl’ before ‘propyl’.

If there are several branches of the same length the number of branches is shown by a prefix and the position of every branch is indicated by a number before the name:

hyphens go between numbers and letters

commas go between numbers

Question 15

what is a structural isomerism

Answer 15

STRUCTURAL ISOMERISM occurs when two or more compounds have the same molecular formula but different structural formulae.

Question 16

waht is the general trend in boiling points when you increase chain length of an alkene

Answer 16

increase

Question 17

are alkanes soluable in water

and what would you expect to see

Answer 17

no

2 layers

Question 18

watch vids on fractional distilation and cracking there is nothing really much on it just have to know about it and what it does

Question 19

what is cracking in alkanes

Answer 19

Cracking is the breakdown of molecules into shorter ones by heating with a catalyst.

Question 20

what is reforming

Answer 20

Reforming is the conversion of straight chained hydrocarbons into branched and cyclic hydrocarbons by heating with a platinum catalyst.

normally produces hydrogen as a sub-product

Question 21

Why is crude oil so important?

Answer 21

Used as fuel and lubricants, valuable source of chemicals
These are used for the manufacture of paints, polymers, pharmaceuticals etc.

Question 22

Why should we try to conserve our reserves of crude oil?

Answer 22

They are a finite resource and a valuable source of chemicals

Question 23

Why is cracking important?

Answer 23

Cracking increases our supplies of the gasoline (petrol) fraction and produces short chain alkenes that are used to manufacture polymers (plastics)

Question 24

What conditions are used for cracking?

Answer 24

High temps >400oC, needed for zeolite catalyst, moderate pressure to move gases through the system

Question 25

Why are governments around the world becoming increasingly concerned about our use of fossil fuels?

Answer 25

Combustion of fossil fuels ---> greenhouse gases ---> global warming, acid rain, smog. They are a finite resource

Question 26

Suggest three ways in which our use of fossil fuels might be reduced

Answer 26

Alternative energy sources – wind, solar, tidal, hydroelectric, biofuels, nuclear Reduce energy consumption Recycling

Question 27

What is the greenhouse effect?

Answer 27

CO2 and CH4 gases in the atmosphere act as a blanket preventing solar energy being re-radiated back out to space

Question 28

How do CO2 levels relate to climate change

Answer 28

CO2 increases global warming ----> melting glaciers,sea ice ---> sea level rises More energy in atmosphere ---> more violent storms; seas warming ----> sea level rises

Question 29

Biofuels are sometimes described as ‘carbon neutral’. Why is this?

Answer 29

Plants photosynthesise using CO2 ---> biofuels Burning these biofuels only releases the original CO2 back into the atmosphere

Question 30

Explain what is meant by ‘sustainable development’, using examples from the manufacture of fuels.

Answer 30

Does not use up non-renewable or finite resources Does not produce large amounts of waste which could have an environmental effect, e.g CO2 ----> climate change, waste bottles, polymers, packaging ----> landfill.

Question 31

info card

Answer 31

Sulfur occurs naturally in crude oil, and although most of it is removed in the formation of petrol it is impossible to remove all the sulfur. During combustion these atoms of sulfur are converted into sulfur dioxide.

Question 32

Give the reaction of sulfur reacting to form sulphur dioxide

Answer 32

S + O2 ---> SO2

Question 33

The sulfur dioxide can then react to form sulfur trioxide

Answer 33

2SO2 + O2 ----> 2SO3

Question 34

Give the equation for the reaction of Nitrogen dioxide and water

Answer 34

2NO2 + H2O ----> HNO2 + HNO3

Question 35

Which pollutant is not removed via the catalytic converter?

Answer 35

Sulfur

Question 36

Note that no fuel is currently 100% carbon neutral why?

Answer 36

Energy in the form of (usually) fossil fuels are still used in the manufacturing and transportation of the biofuel

Question 37

what is the general eqation for an alkane reacting with chlorine in ultraviolet radiation use methane as the alkane what type of reaction is this

Answer 37

CH4 + Cl2 ---> CH3Cl + HCl has to be in concentrated chlorine free radical substatution

Question 38

what are the three steps of free radical substitution

Answer 38

ultravoilet UV light breaks the chlorine molecule which produces two chlorines with one unpaired lone pair

Question 39

what is the definition of HOMOLYTIC FISSION

Answer 39

HOMOLYTIC FISSION (homo- of like kind, lysis-to break open) is the term used to describe the breaking of a covalent bond so that the bonding electrons are shared equally between the atoms involved. It is represented using half-headed curly arrows.

Question 40

what are free radicals

Answer 40

FREE RADICALS are molecular fragments or atoms with one unpaired electron. They are highly reactive.

Question 41

what is a substitution reaction

Answer 41

SUBSTITUTION REACTION where one atom or group of atoms replaces another atom or group of atoms

Question 42

draw out the propagation step for chlorine free radical with methane and also the step in which the free radical is regenarated

Answer 42

https://crunchchemistry.co.uk/free-radical-substitution-reactions/