Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

A-level CHEMISTRY > Module 4.1 > Flashcards

Module 4.1 Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Chemistry flashcards Periodic Table flashcards Chemistry 101 flashcards Organic Chemistry 101 flashcards
1
Q

Organic Chemicals

A

Covalent molcuelces based ont he element carbon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

check sheet for examples of alcohol

A

-lines represent the COVALENT BONDS
-All of these molecules are based ont he element CARBON

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

KEY

A

carbon atoms have FOUR COVALENT BODNS
hydorgen forms ONE COVALENT BOND
oxygen forms TWO COVALENT BONDS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

These moelcules on the sheet have two parts
check star one

A

-Chain of carbon atoms bonded to hydorgen atoms .
-This part of the moelcule is called of the hYDROCARBON CHAIN
-the length of the hydrocarbon chain is dependant on the molecule .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

check star two

A

-each moelcule also contains a second part
-the o-h ocygen covalnet onded o the hydrogen alcohol group is what scientists call thisese .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

all of these molecules react int he same way but why ?

A

as they all contian an alchol group referred to as the FUNCITONAL GROUP OF ORGAIC MOLECULES .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is a functional group ?

A

Prt of the moelcule that deretmines how it reacts (alchols all react ina simialr way becuse of their functional groups .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Alcohols are a homologous series , what does this mean ?

A

they have the sae fnctional group but each sucessive meember has an additional -ch2 .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

my functional gro pis cll
example of me is cholormethane
wat is me ???

A

CHOLOROALKANESSS
yummyy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

family of organic molecules is cALLED hydrocarbons

A

hydrocarbons are covalnet compounds containing only the elements carbon + hydorgen .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

check sheet for all the hydrcarbons drawn

A

ETHANE has a SINGLE covalnet bond beween he carbon atoms .
-HYdrcarbons that only have a single covalent bond bewteen carbon atoms are called SATURATED hydrocarbons .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

ethene has a double covalnet bond between caebrn toms
ethyne has a triple covalnet bond between carbon toms

A

any hydrocarbon with double / tirple covalne bonds betwen carbon aroms are called UNsatruaed hydrocarbons .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

ethane is a memeber of the alknane homolgous series key though

A

-Alakanes have NO FUNCTIONAL GRoup BUT STILLR EFERRED TO AS homoglous series

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

part one of naming alkanes

A

1.the first paert of each name (aka prefix) tells u the NUMBER OF CARBONA TOMS

TABLE ON SHEET MUSTT LEARN AND KNOW

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

prefixes can also be used to name alkenes

A

alkenes with 3 carboncatoms
-name of all alkenes end in ENE .
3 carbonaTOMS SO PREFIX IS prop ene . PROPENE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Issue with alkenes with mroe than carbona toms

A

-the double bond cn be in different postions .
-TO nme the molecules we have to show the position of the double bond .
-TO OD THAT WE NUMBER THE carbon atoms .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

-look at the shhet

A

-the double bond les betwen carbon 1+2
-in the name , we use the LOWEST OF THE TWO NUMBRTD that the double bodn lies in .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

as the double bond lies betwen carbon 1 +2

A

the moelcule i called but 1 nee
check sheet of ranother example

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

-a carbon chain can me numbered frome ither left or right so wheere do we start ?

A

You choose the ned that to produces the LOWEST POSSIBLE NUMEBRS check sheet for the example .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

in alkenes

A

we use a number to show the position of the double bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

example of a branched chain hydrocarbon

A

branched chain hdyrocarbonds have a side chain / branch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q
  1. of naming
A

start by identifying hte longest ahin of carbon atom
the longest chain is 7 carbn atoms LOOK VERYY CAREFULLY WHERE IT IS .
-alaknes with 7 carbon chians are called heptane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q
  1. naming
A

look at the number of carbon atoms in sid chain
side chain has one crbon atom check dstar one .
-go back to the table - ONCE CRBON ATOM HAS THE PREFIX METH .
-so we call the side chin with one carbon atom the methyl group .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q
  1. of naming
A

State the positon of the methyl group on the main carbon chain .
-to do tht we number the carbon atoms .
-do this from the left the methyl group IS ON CARBON .
this is the right one
so the moelcules name is 3METHYL HEPTANE
(postion of chain how manyc arbon atoms then LONGEST Carbon chain )

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what if we had two methyl groups on carbon 3 ?
check sheet

A

3,3DIMETHYLHEPTAINE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

check sheet again

A

3,5 DImethylheptaine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

check example 2

A

do not be caught out , the longest carbon chain is FIVE CARBON S .
-where is the methyl group on cabron 3
3methylpentane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what if we have two side chains and they are not the same ?

A

check sheet
-idenitfy the lonesgt chins
and name sof side chian .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

-the name of the molduelse is based on the LONGEST chain

A

-Side chains are listed ALPHABETICAL witht he lowest possible numers .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

worked out of example with two side chaons in dif places

A

-longest chain is 8 = octan e
one isde chian = methyl as one carbon
another side chain = 2 cabrons ehtyl group
POSTIONS = methyl is on carbon3
ETHYL is onc arbon 5
IF U WERE TO NUMBER FROM LEF TTO RIGHT , the lowest numbers woudl nt be produced .

-SIDE CHINS ARE LISTED ALPHABETICALLY
name is
5ethyl,3methylloctane .
E COMES BEFORE M ,

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

same rules apply with branched alkenes

A

-longest carbon chain is five atoms .
-double bond is between crbon2 and ,
so it is based on PENT-2-ENE
-Methyl grou pis on carbon 3 os moleeucl eis called 3METHYLPENTANE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

STRUCUTRE of methane

A

-methane has one cbron tom
joined byc oelnt bond to four . so molecular formular is ch4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

molecular formula

A

the molecular formula ells sus the elemnets in a molecle and then umber of toms o feach elemeent methnae = ch4 .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

emprical forumla

A

tells us hte ismplest whle number ratio of the the atom sof each element in a compound o fncl
one to one ratio so emprical formula is nacl

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

whe writing moleuclar forumala of orgnic moelcules always but c before h and then ny other elements are listed alphabeitclaly

A

…

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

one problem with molecular formula

A

does not give us an information on the strucutre of the moleucle 9how the aotms are bonded to eachother )

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

second problem with the moleuclar formula

A

different compounds can have rs can have the same moleuclr formula

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

C2H4 O2

A

ethanoic acid and methyl methanoate
-cant tell from the moleuclar forumla alone which compound e are discussing .
emprical forumla c2h6 divide by smallest number HICH IS 2
empricl formula is CH3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

IN EXAM , COULD BE ASKED TO WORKOUT THE EMPRICAL FORMULA USING DATA

A

a sample of hydrocarbon contains 0.48g of carbon and 0.08 gh of hdyrogen
calculate emprical formula

STEP ONE - wokout the moles of carbon ahd hydrogen by doing
MOL = MASS /MR

so mol of carbon is 0.04 and moll of hydorgen is 0.08
DIVIDE BYTHE SMALLEST MOL WHICH IS 0.04 U WILL GEt emprical formula as ch2 .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

empirical formula is used to worko out the moelulcar formual .

A

we know our ocmpound ofr example has a mr of 28gg1. get hte mr of our empricl formula = 14
divide mr of compound by mr of empricl formula =2
times our empricl formul by 2 = C2H4 menng our compound is ETHENE .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

DISPALED formula of hydorcarbon propane

A

c3h8
3 carbons and eighth ydorgens .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

key ; displayed formula

A

shows us the relative position of each atom and all the covalent bonds .
-KEY ; displayed formual does not show accurate bond angles .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

however , rather than displayed formula - scientists prefer using structural formula .

A

structural formula shows us how atoms are arranged but does not show bonds .
KEY ; need to show atoms bonded to each carbon atom in turn . CHECK SHEET AND DLOOK AT PENTANE TOO .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Two different versions of chloropropane

A

check sheet these are called isomers
chlorine is afrer CARBON1 in the strucurl formula
-chloirne is after CARBON2 in the strucuturl formula .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What if we need to show a side chain in the structural formula ?

A

-methylpropane
ch3ch(ch3)ch3
-methyl group of carbon atom with 3 hydorgen atoms .
-In the strucural formula , we place the meythl group in BRACKETS
-As the methyll group is bonded to carbon 2 , In the strucural formul we put it after C2 .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

alcohol group check sheet

A

key about the alcohol group is hat the covlent bond runs from the Carbon aatom to the oxygen atom so need to show in the moleucle .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

what is skeletal formula ?

A

Skeltal formula is the simplest possible way to show the strucuutre of an organic molecule .
-we do NOT show crbon nd hdyrogen toms .
-Only atoms we show are FUNCTIONAL GROUPS
-Instea we show the ocvalnet bonds between cabron atoms and bond to functionl roups . LOOKA T EXAMPLES ON SHEET .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

FINAL EXAMPLE

A

Haven’t shown the covalent bond between oxygen and hdyrogen in fucntional group as it is not a critical to show the bond in the funcional grous (will say if it is essentail thoghghghg)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

what is is the general formula

A

the general formula is the simplest algebric formula for a memeber of a homoglous seris

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

what is the general formula for alkanes and alkenes

A
  • generral formula for alkanes is cnh2n+2
    general formula for lakenes is cnh2n
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

workout thecholroalkanes

A
  1. each moleucle has two hdyrogen atoms bdoned to a caron atom .
    -have one extra hydrogen at the end of each molecule .
    -each moelcule also contians one atom of chlorine .
    so genral fromula is CNH2N+1CL
    This step by step process applies to all .
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

general formula for alchols

A

CNH2N+105
HAVE TO show rthe whole functional group . .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Check sheet for formula for butane

A

Butane is an alkane with the molecular formula c4h10

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

What other thing had the molecule formula c4h10

A

Methyl propane
Butane and methyl propane ahve the same molecular formula , but different sirry curls formulas . Theses are called STRUCTURAL ISers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Meaning of structural isomers

A

Molecules work the same molecular formula and different structural formulas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Chekc sheet for different structural formulas of pentane and learn them

A

…

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Check sheet for different structural isomers of pent-1-ene and learn them

A

Change rhe poison of the double bond and you get pent2-ene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Another one

A

Pent-1-nee move carbon 5 to carbon 2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Another one 2-methylbutene

A

Take methyl group on and move methyl group onto carbon 3 , to get 3 methylbut1ene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

Taking pent .2ene

A

We can move carbon 5 onto carbon 2 giving structure 2 methyl but 2 ene
And that is all of them .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

Key : ask nws ask have structural isomers which are called cycloalkanes

A

Check sheet for cycloalkanes of penitence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

Check sheet for structural isomers of 1-chlrprnjtanr (learnnn)

A

Some stringers nah be r thoight there was a fifth structure isomer . WITJ THR FIFTH CL ON THE methyl group but that’s jus another wya of smdraeing methul ptopane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

Sometimes , different structural isomers have different functional groups .

A

Check sheet and lesrn

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

What is a functional group isomer

A

Functional gorip jsomers the molecules have the same molecular formula but different functional groups .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

Chain isomers

A

They diffeeent in the arrangement kf the hydrocarbon chain . Two examples SHEIN a

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

Positional isomers

A

Have different positions of the functional group . On the hydrocarbon chain , one chlorbitane and 2chlorobutane are examples .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

What re stereoisomers

A

Stereosisomers are moelcuels with the the same struccutrl formula butatoms are arrnged differently in space .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

Stereoisomers

A

Stereoisomers are molecules with the same structural formula, but atoms are arranged differently in space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

There are two main types of stereoisomers

A

Geometric jsomers
And optical jsomers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

Chekc the sheet for 1,2 dibromowrhanw

A

KEY: single covalent bonds are fully rotational . AKA THE covalent bond between the two carbon atoms can rotate .
All of the diagrams shown for the same molecule all that has been done is in each case is rotate the carbon bond between the carbon mains.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

Showing in sheet 1,2 dibromoethene

A

Double covalent bonds have very resiteicfwd rotation.
A double covalent hind can flex slightly . But cannot rotate like a single covalent bind . This means that this meolcule actually exists in two different forms .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

1,2 dibromowrhwne

A

These are called geometrical jsomers or 1.2 dibromowrhwne check sheet
One is CIS and one is TRANS

KEY : cis/ trans jsomers is one of the naming systems for gemeoteixal jsomers . The other one is E/Z

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

Any aleeena can have cis/ trans jsomers as long as it needs to conditions.

A

…

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

Condition one

A

Carbon atoms on the Dublin bond must have attached to 2 different groups.
Can see this in the monster drawn before.
Both carbon atoms on either side of the double bond is bonded to a bromine atom and a hydrogen atom.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

Condition two

A

At least one of these groups must be the same, on both carbon atoms on the double bond (in the in the case store, it is actually true for both the hydro and the bromine.)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

Step one on deciding which is which.

A

Look at the group which is the same on both sides of the double bond. In this case we can choose either hydrogen, atoms or bromine atoms. We’re going to choose the hydrogen atoms in this case.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

Step two of deciding, which is which

A

– If the two hydrogen atom are on the same side of the molecule, then this is a CISI.
– however, if the two hydrogen atoms are opposite the molecule than this a trans is OMR .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

SIS/trans, isomers for BUT – two – ENE

A

In the case of this, the carbon atoms are on either side of the double bond and are both body to a hydrogen atom and meter group. We are going to stick with the hydrogen again.
– In the C.I.S. is more hydrogen atoms are on the same side of the molecule (diagram on left).
In trans, isomer and opposite size of the molecule, check the right side.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

Why can’t But1Sbe have any cis trans isomers

A

What is carbon atoms on either side of the double bond must be to 2 different groups.
– at least one of those groups must be the same for both carbons.
Looking at but one ehe we can see carbon one bonded two hogging atoms, so but1sbe is not a cis trans isomer .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

What about 1-xhlorobut1eneq

A

This can have system isomers as a carbons on either sides of double bond is bonded to 2 different groups. (Carbon one is bonded to hydrogen and chlorine atom.
Carbon is bonded to a hydrogen atom and eat our group.
So here is the C.I.S. Trans isomer for 1-chlorobut1ene, check sheet .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

workout e/z isomer , how do we do it ?

A

start by looking at the grop ,kw hich is thw same , on the carbon atoms on either side of the double bond .
+-In

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

How do you workout E/Z isomers ?

A

Start by looking at the group which is the Same on the carbon atoms on either side of the double bond .
In this case we are looking at the hydrogen atom .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

Workout Z isomer

A

If the group is ok the same side of the molecule then we fall it a Z ISOMER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

If the group is on the opposite soxd of the isomer

A

We call it the e isomer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

Ada vantage of cis trans jsomers

A

Check sheet , in this case , the carbon atoms on either side of the double bond are attached to four diffferent groups .
-so we cannot name these isomers using cis/trans system .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

BUT , we can use due E/z isomer rule
And to do that we use the CIP priority rules (initials from scientists who developed this )

A

…

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
83
Q

Step one of using CIP rules

A

lol at the atoms attached to the carbons on either side of the double bond
The element with the greatest atomic number is given the highest priority .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
84
Q

-On the LHS we have cl and br
Chlorine has atomic number 7 and bromine is 35

A

So on the lhs bromine has higher priority .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
85
Q

On Hydrogen has ar
If nimber onefluroine has nine RHS

A

So on the right hand side flooring has the higher priority. 

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
86
Q

We assigned the EOD using the higher priority groups. LHS – higher priority groups on the opposite size of the molecule so this is the E isomer .

A

HS – higher priority groups are on the same side of the molecule, so this is the z isomer .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
87
Q

Next molecule carbon atoms are on either side of the double bond, have completely different groups.

A

LHS of the double bond we have a bromine atom and a iodine atom.
Bromine has an atomic number of 35 and iodine has an atomic number of 53. So iodine has a higher priority.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
88
Q

RHS of the double bond – carbon atoms attached to 2 atoms of oxygen.
Therefore cannot establish priority based on oxygen.
So now we move onto the next atom, if there are different, we can use these to establish priority.

A

I uncover. The atomic number of hydrogen is one and atomic number of carbonate six.
Meaning group containing carbon has a higher priority.
LHS – high priority groups are opposite size of the molecule, so it is a
R isk ed. .
RHS same side , so Aaron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
89
Q

Determine the e / z isomer of this check sheet

A

HS – hydro atomic number of bond and chlorine atomic number seven. Chlorine has a higher priority.
RHS carbon is one to another carbon so we cannot use this for priority.
Then we have carbon and nitrogen. Carbon has an atomic number of six and nitro atomic number seven. Nous containing group has a heartpriority

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
90
Q

General formula of allanes cnh2n+2

A

Covid bonds all each carbon atom, phones, tetrahedral structure with bond, angles of 109.5°

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
91
Q

The bond angles in alkanes are type of covalent bond, Calls a sigma bond

A

Aia bond forms when electron orbitals from adjacent orbitals directly overlap .
A sigma bond contains a parallel one from each atom, either side of the bond. The par of electrons in the bond directly between the bonding atoms.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
92
Q

When we look at our Keynes, we can see that carbon atoms. You can’t force a different type of corrode and bod called pi bond .

A

However, in the case of alkanes, only a sigma bond can be formed.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
93
Q

Key: sigma bonds are fully rotational.

A

The covalent bonding in alkanes are also relatively strong. And take a lot of energy to break.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
94
Q

Alkane is a hydrocarbon. Carbon hydrogen atoms have very similar electronegativity. Many alkanes are essentially non polar molecules.

A

…

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
95
Q

Helping to explain the properties of alkanes.

A

Alkanes are insoluble in water. Because water molecules from hydrogen bonds with each other. 

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
96
Q

Because our kids have no permanent diapers, they can some hydrogen bonds. Therefore, I’ll keens cannot dissolve in water.

A

Online money or molecules alkanes are generally unreactive. Because of this strong covalent bond within an alkane molecules.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
97
Q

Certain conditions, arcades will react.

A

If we look at the boiling point of alkanes, we can see interesting, as the length of the carbon change increases so so temperature.
Long-term archives have a higher boiling point as the carbon chain-link increases, we find the arcades at liquid and solids at room temperature.

98
Q

You can explain this pattern by looking at the intermolecular forces in alkanes.

A

Alkanes are non-polar, so the intermolecular forces acting between alkane molecules are included, dipole, dipole interactions.(London (dispersion forces.

99
Q

When we boil an alkane, we have to break these intermolecular forces – however, London forces are weak forces and do not take a lot of energy to break. Explaining why shorter chain alkanes have a low boiling points.

A

…

100
Q

As the length of the carbon shade increases, strength of land forces also increased

A

There are two reasons for this.

101
Q

Number one longer train alkanes have more electrons than shorter chain alkanes (strength of the London forces going go up if the number of electrons enquiries, close bracket.

A

A second reason – longer train alkanes have a great surface area then short to train alkanes. Meaning that there are many points along the molecule. They can form London forces,.
Increasing number of electrons and increasing surface area increases London forces in Longtain arcade, so have a higher boiling point, then shorter chain alkanes

102
Q

Branched chain alkanes have a lower boiling points and straight chain alkanes.

A

As branches, prevent the arcade molecule from getting close together. And London forces are strongest at shortest distances, so in branched chain, alkanes to London forces are reduced.

103
Q

Alkanes are extremely useful compounds

A

Alkanes are used extensively as fuels .
Alkanes are used as the starting materials for produce of the whole range organic molecule, including pharmaceutical.
You find arcades in crude oil
Crude oil is a fossil fuel and formed on the ground from the remains of plants and animals.
– Over millions of years, heat and pressure. Convert the chemicals in these remains crude oil. 
As we are using crude oil, faster than it’s formed, it’s non-renewable resource.

104
Q

What is crude oil?

A

Cradle is a mix of street chain and Blanchard arcades. Along with other chemical sulphur.
– Use these alkanes. You need to separate them using for distillation tied out column.
In order to understand fraction station, need to need to learn about the full of arcades.

105
Q

Crude oil molecules are attracted to each other by intermolecular forces.

A

As alkanes are nonpolar – they have the forces.
Key: long-term hydrocarbons have a greater serve area for formation of London forces, compared to shorter chain, alkanes. Meaning, it takes more energy to break the London forces in longer chain alkanes, so they have a higher boiling point, then shorter chain arc arc.

106
Q

Key: octane alkane – octane boilers at 126°.

A

If we take liquid octane and heated to 126°, it boils converting to a liquid to a gas.
If we take as a gas and we call it below, it’s boiling point it will condensed back to its liquid for (applies to any alkane.)

107
Q

Step, one of fractional distillation

A

Crude oil is heated in the furnace. The temperature of the furnace is hot enough enough to boil a lot of the alkanes in the crude oil, converting them to a gas.

108
Q

Step two of fractional distillation

A

Next, the crude oil, vapours and liquid pass into the fraction column. The column is hotter at the bottom and become progressively cooler going upwards.

109
Q

Step three of fractional distillation

A

No, the crude oil, vapours, make their way up the column. A different levels of the column, we have collecting traits. These trays have bubbles, something which allows vapours to pass upwards.

110
Q

Step four fractional distillation

A

As each alkane moves up the column, at some point, it will read, which is cooler than its boiling point.

111
Q

Step five, a fractional distillation

A

Now the alkane condenses back into a liquid and passes out the column. This alkane with shorter carbon chains have lower boiling input. so we collect them at the top.
Long chain arcades have a high boiling point, and therefore collect at the bottom.

112
Q

All okay with a very long chain from a thick liquid called bitumen and this is collected from the bottom.

A

…

113
Q

Not all the alkanes will condense. Very shortened arc, that methane and Ethan are collected at the top as gases.

A

Key: fraction desolation does not separate each individual arcade.
Instead, each fraction contains a number of alkanes with similar boiling points. To separate each individually, we need multiple rounds of fractional distillation.

114
Q

Why is the petrol/up the fraction, particularly useful.

A

The fraction is used to make petrol in vehicles and as of raw material for the chemical industry.

115
Q

But what is the problem with the problem with the petrol/NAPA fraction

A

Crude oil tends to contain a high proportion of long contain hydrocarbons, then solitude. So when we carry the crude oil, we did not produce the last amount of the petrol/the fraction.

– In contrast, we produce more of the longer term fractions which are less demand. Because of this, there is an economic benefit to converting long chain, hard carbons disorder, hard carbons. We do this wire process called cracking.

116
Q

One benefit of cracking

A

Cracking converts, long chain, hydrocarbons into short hydrocarbons.

117
Q

Second benefit of cracking

A

As well as producing alkanes, cracking water produces alkanes.
Unlike alkanes, which are highly reactive molecules.
Alkanes are a major feed stock (warm material) for the chemical industry and are used to make a range of products, including polymers.

118
Q

There are several ways to carry a cracking.

A

The two methods include thermal, cracking and catalytic cracking.

119
Q

What is needed for thermal cracking.

A

Thermal cracking requires both a high temperature and a high-pressure.
– Needs to be around 450 to 900° and the pressure is around 70 atm
Arcades are converted into short chain ales ales and Al Keynes.

– Hydrogen can also be one of the products. The product shown examples of what we could produce.
However, I should point out that the specific products depend on the exact conditions.

120
Q

The benefit of using thermal cracking

A

Internal cracking, we make a high percentage of lakebed in produce in the products and as we’ve seen, our canes are very useful molecules due to their high reactivity .

121
Q

In the exam you could be also complete. Cracking quiz like this. Given the starting molecules and the sum of the products. 

A

Remember: the total number of carbon must be the same on both sides of the equator. In different isomers are possible, then that will be taken into account in the question.

122
Q

What happens during thermal cracking step one

A

A Covid and bond between the two carbon atoms splits. To form a molecular molecules.
Remember, covalent bond is a pair of electrons.

123
Q

What happens during the cracking step two

A

When the covalent bond splits, both of the intimate in Michael, now fuse, one unpaired electron. Scientist called isn’t molecule like this for free radical.
Key, don’t need to know the mechanism for thermal cracking.

124
Q

What is needed for catalytic cracking?

A

Class is a cracking auto, requires a high temperature 450°.
However, catalytic Cratic cracking does not require high-pressure.
, In fact, the pressure of catalytic cracking is about one to 2 atmospheres.

125
Q

What extra thing does catalytic cracking need?

A

Catalytic crack and use a zealite list. Which contains a mixture of aluminium oxide and silicon dioxide.
Zeolite has a large surface are called an effective catalyst.

126
Q

What a long okay undergoes catalytic, cracking. The products are often branch chains.

A

What arcades are special used for petrol as they combust very efficiently.
– Catalytic crack also produce cyclic hydrocarbons like benzene. 

127
Q

Alkanes are very unreactive, why?

A

Nonpolar as carbon and hydrogen acids are very similar electronegativity.
In later, flashcards, you will see many molecules that react due to the polarity, so because they are non-polar, arcades are not very reactive.

128
Q

Open (two) why are alkanes unreactive ?

A

The bonded arcades are relatively strong. And take a lot of energy. Again, making them unreactive molecules.

129
Q

What is one way that alkane can react?

A

Buy free radicals (a.k.a. as radical)

130
Q

What is a free radical?

A

A free radical is any species with an unpaired electron. Two examples, shown on sheet. We have the rhyming for radical and the meat through radical. You show the unpaired electron as a dot.
Key card free radicals are highly reactive species. Even though alkanes are unreactive molecules, they can react with free radicals.

131
Q

Free radical reaction between alkanes and halogens.

A

Reaction between methane and bromine.
So the hydrogen atom on the methane molecule, has been substituted with a bromine atom .
And this reaction has a free radical, this reacted example of a free radical substitution.

132
Q

We can also see if radical substitutes in the reaction between methane and chlorine.

A

I’m showing you that equation.
We also see free radical substitution the reaction between me and chlorine.
Showing that equation here.

133
Q

Looking at the stages between me and chlorine.
These can also apply to any alkane and also chlorine as well as bromine.

A

There are three stages in this reaction.
Initiation
Propagation.
Termination

134
Q

At the start of the reaction, we have a mixture of methane Roman molecule BR2.

A

First – initiation.
We shine UV light onto the reaction mix. The end of the UV light causes single covalent bond between the two bromide atoms to break.

135
Q

Part two of initiation

A

You need to remember that a single covalent bond consist of a power of electrons.
– When the bond breaks like this come on one electron now goes to eat breed atom.

136
Q

Initiation initiation, part three

A

Because these now have an unpaired electron, these are bromine free radicals.
– When a covalent bond split in this way, scientist called this homolytic fission .

137
Q

Initiation part four

A

I should point out, we only require a few of the broken monitors to form free radicals , in the initiation stage.

138
Q

Propagation part one

A

Romy through radical reacts with a methane molecule.
Remember that a Free Radical has an unpaired electron. To make an electron pair, the bromine Free Radical , takes a hygiene atom plus one electron from the methane molecule.
In order to illustrate this, electrons are shown in the covalent bond in the methane molecule as a gree green dots.

This reaction produces both a hydrogen bromide and a methyl Free Radical

139
Q

Propagation, part two

A

The methyl free radical now reacts with a bromine Melville , producing our end products bromoethene and another bromine free radical .

140
Q

What do we see if we look at steps one and two in propagation?

A

We can see that they form a chain reaction.
The bromine Free Radical formed in propagation, step two. Can now go back react with the methane in propagation step one.
– This will continue until the final stage which is called termination.

141
Q

What happens in termination?

A

Two free radicals react together form molecule with no unpaired electrons.
– This is now a stable molecule and no longer takes place in the reaction.

142
Q

There are three possible reactions in termination.

A

…

143
Q

One possibility

A

Two bromine, free radicals, can form a bromine molecule.

144
Q

Second possibility

A

To meet all three radicals can form a molecule of ethane.

145
Q

Third possibility

A

Or , Amith are free radical under bromine, free radical conform molecule of Bromoethane

146
Q

What is the problem of free radical substitution of alkanes.

A

We get a whole range of side products.
Example bromine free radical, reacts with a molecule of bromoethane then we make dibromoethane .
Can get further reactions to form tetrabromoethane .

147
Q

What happens in the termination step?

A

In the termination step, we can make Ethan.
This ethane can also react with bromine free radicals.
Forming, all molecule step .

148
Q

In termination, what happens if we carry out the reaction with longer chain alkanes, for example, pentane.

A

We could produce a whole range of product molecules.

149
Q

Some teachers use curly half hours, describe radicals such as

A

However, we don’t need to use this.

150
Q

Alkane ethane for example

A

Alkanes or saturated hydrocarbons with a general formula cnh2n+2
All the Covalent bonds in alkane are sigma bonds .
Sigma bonds form when electron orbitals directly overlap.

151
Q

Key ideas

A

In alkanes, bond, angles tetrahedral (109.5°.)
– Sigma bonds are really rotational.

152
Q

Structure of the alkene ethene example

A

Unsaturated hydrocarbons with general formula cnh2n.
Thing to notice is that ethene is a planar molecule .
We looked up planar molecules in the topic of structure, bonding .
Planar normal molecules of flat, with all the atoms lying on the same plane .

153
Q

Remember when working out molecular shapes we treat both single and double bones as bonding regions .

A

We have three bonding reasons around each carbon atom .
These bonding regions repel and move as far apart as possible.
– Meaning that bond angles around carbon atoms are around 120°.

154
Q

The bonding in ethene is different to ethane due to the double bond .

A

Just likee ethane , ethene has signs finds between carbon and hydrogen atoms .
However, the double bond actually consist of two types of Covalent bondd ,
When the double bond forms, we form one sigma bond between the carbon atom.
At this point, each carbon atom has one electron left in a p orbital.
These orbitals lie above, and below the plane of a molecule.

155
Q

The two p orbitals over up sideways and form a covalent bond called a pi bond ,

A

Which is above and below the sigma bond.
Key: even though overlap occurs above, and below the sigma bond, we only form one PI bond .

156
Q

Key: double bond in our Keane actually consist of both a sigma bond and a PI bond. Which has a major effect on the structure and reactivity of alkenes.

A

…

157
Q

Difference between sigma bond and PI bond

A

Unlike sigma bonds, a PI bond can rotate.
That’s because any rotation would reduce the overlap of the p orbitals .

158
Q

Second difference between the sigma bond and the PI bond

A

As the PI bond cannot rotate, this means that the structure of an alkane across the double bond is actually locked. Can see this so with 1,2 sicholroethene . As the molecule cannot rotate, the molecule exist as two isomers E and Z isomers.
– Al form stereoisomers as double bonds. Can’t rotate.

159
Q

Number two, why are are highly reactive

A

Due to the double bond.
– Bond and enthalpy of pie bond is less than a sigma bond.
As PI bond is a sideways overlap of the orbitals, where I was in a sigma bond, the orbitals directly overlap.
– As the orbitals over up sideways, PI bond is easier to break.
– As it takes less energy to break PI bond, it is more likely tobreak in a reaction.

160
Q

A double bond consist of two pairs of electrons

A

So we have a par of electrons in Sigma bond and parallel electrons in PI bond.
Because of this – double bonds is a reason of high electron density. This high electron density makes alkenes reactive molecules.

161
Q

What does a double bond consits of

A

a double bond cosnits of sigma bond and a pi bond .
-Both of these bodns contain a pair of electrons . so the double bond in alkenes actually consits of four electrons .
-this region of high electron densitry determines how alkene reacts .

162
Q

There are three hydorgen haldie

A
163
Q

What do we have in a double bond

A

A double bond consists of
A sigma bond and a pi bond . Both of these bonds between the pair of electrons.
For the double bond in alkrned Actually consists of four electrons, meaning the double bond is a region of high electricity.
This reason of Hi electron density determines how alkrned react . 

164
Q

Alkrned react by a process called electrophilic addition.

A

A Reaction between alkenes and hydrogen halides .

165
Q

So there are three are you, Hydrogen halide molecules here.

A

Key: halogen atoms are more electronegative than hydrogen.
This means hydrogen halides molecules. Have a permanent dipole.
As you can see, in the hydrogen hate, I don’t want to, the hydrogen atom Has a very positive charge on the halogen atom has a small negative charge.

166
Q

How hydrogen halides reacts with Ethan we have to learn this reaction mechanism. Stage one

A

Hydrogen bromide, Molly to approach is the alkrned
The positive hydrogen on the hydrogen bromide is attracted to the high electron density of the double bond, scientists call this and electrophille.

167
Q

What is an electrophillr

A

Is there any positive ion molecule which is attracted to a region of high electron density.

168
Q

So, in this case, the positive hydrogen atom in the hydrogen bromide is acting as an electro file

A

The positive charge on the hydrogen atom, attracts the power of electrons in the pie bond of the alkene.
This pair of electrons move
Towards the hydrogen atom, and we use a curly arrow to show that power of electrons.

169
Q

Key points about the hydrogen halides reaction mechanism

A

– A covalent bond is a pair of electrons.
– When you draw a curry hour, make sure that the arrows starts exactly whether electrons are moving from and ends exactly where they are moving to.

170
Q

Stage three

A

As you can see, covalent bond is not forming towards the hydrogen atom, in the hydrogen bromide. This presents a problem

171
Q

What is the problem?

A

Abhay didn’t atoms can only have one covalent bond. So come at the same time, the pair of electrons in the covalent bond between the hydrogen and bromine now move onto the bromine atom. Shown as a curry Aaron.

172
Q

Stage five

A

When a covalent bond, breaks like this, with both electrons, going to one atom, scientist called is heterolytic fission.

173
Q

Stage six

A

St the end of this stage we now have two products .
-we have a positively charged intermediate molecule formed from
The alkrne .scientists call this the carbocation intermediate.
This contains a positively charged carbon atom.

174
Q

Why is this carbon atom positively charged?

A

Because it has lost its share of the electron pair that What in the pipe on.
– We have also found a negatively charged by my own come on. This is a negatively charged because, both of electrons are in the cupboard up come on out on the Brokide ion .

175
Q

Key point about this Resction

A

Number one if we were to look at the whole creation, we can see the hydrobromide has added to the Ethene Examples of an Alexa.
.2, the Allen’s in thsi reaction id ethene Which is a symmetrical Monica. Meaning I can only make one for product.
However, if we were to carry out a asymmetrical alkene like but 1 ene Then we can make two possible products.

176
Q

key ; when we add a hydorgen halide to symmetrical alkenes we form one porduct

A

showing addition of hydrogenbromide to the symettrical alkneen but2-3n3 .
-Showing carbocation inermediate withthe postiive charge on the carbon 2 , Making porduct 2bromoethane .

177
Q

Showingresction again , but this time the carbon atom intermediate has a positive charge on. Carbon 3 .

A

….

178
Q
A
179
Q
A
180
Q

Some might think we make the pros cut 3-brooo butane but why is not the gas e.

A

We always number from the carbon atom that will produce the lowest possible numbers .
-if we number from the right most carbon we can still make 2brokoburaje .
SO NEED TO REMEMEBER WE ADD ABHUDIRGEN HAOODE TONSUKMERRICAL WE ONLT MAKE one product .

181
Q

Allen’s but1ene . Asymmetrical Alkene .

A

When an asymmetrical alkene reacts with a hydrogen halide molecule we can actually form two isomers .
THIS ADEPENDS ON WHUCH carbon atom has the positive chathe in the carbocation intermediate .

182
Q

If the positive charge is on carbon 1 then we make 1bromobursne .

A

It can have a positive chathe on the carbon 2
We make 2bromobutane .
KEY : we dont make equal amounts of these products .
We actually make a lot more 2/brokortuane then 2 bromoethane .

183
Q

1-bromobitsne is a minor product
2-vrombjtane js a major product . Why

A

Idea is that a carbocation intermediate is on unstable molecule thag only exists for a short period of time .
-the stability of the carbocation depends on how many alkyl groups are bonded to the carbon atom with the positive chathe. .

184
Q

What is an alkyl group ?

A

An alkyl groip is a group containing a carbon and hydrogen atoms . This is shown in red .

185
Q

If the positive carbon atom is bonded to one alkyl group

A

It is called a primary carbocation .

186
Q

If the psofige carbocation is bonddd go two alkyl groups

A

We call this a secondary carbocations .

187
Q

KEY : secondary carbocation is more stable than a primary carbocation . As it is kore stable IT EXISTS FOR a

A

Longer period of time .
Therefore is more likely to form a product , explaining why 2brokobutane is a major product and 1bromobutsje is a minor product .

188
Q

How to determine major minor product

A

Look at markowikoffs rule
When a Hydrogen halides reacts with an asymmetric alkene, the hydrogen atom of the hydrogen HALD or is more likely to bond to the carbon atom which is attached to the greater number of hydrogen atoms.

189
Q

Putting the rule into practise

A

Going back to but1ene , one can see that carbon 2 is bonded to two hydrogen atoms .
Whereas carbon3 is bonded to only 1hydirgen atom . -so in this case , the hydrogen of the hydrogen bromide is more likely to bond with carbon 1 . So 2bromothingy is major product .

190
Q

Explain the alkyl groups

A

As we have seen , secondary carbocations are more stable than primary carbocations .
That is because the electrons in the alkyl groups can shift towards the positive charge .
-the effect of this is to stabilise the positive chagve . Scientists call this the POSITIVE INDUCED EFFECT .

191
Q

In primary carbocations , the positive charge is stabilised by only one alkyl group . Whereas in secondary. Carbocations z, the positive chathe is stabilised by two alkyl groups .

A

Making it MORE STBALE that primary carbocations .

192
Q

2-methyl but1ene - this can form secondary or tertiary carbocaitisb

A

The tertiary carbocation had 3 alkyl groups bonded tk the positive carbons rom .
/making the terraria cabdocaitons even more stable than the secondary carbocations . So the major product would be from the tertiary carbocations .

193
Q

Showing reaction between ethene and bromine .

A

-in this reaction , the halogen molecule adds across the double bond .
-another example of electropjile addition hair et as we will see the mechanism is slightly different .

194
Q

Why is the mechanism slightly different with halogens ?

A

As halogen molecules do not have a permanent dipole .

195
Q

Stage one for halogens .

A

-first stage of rs film , bromine molecule approaches the ethene molecule .
-bromine Dosent have permanent dipole , however , we double kind of the alkene is a region of higher electron density .
-fhis huhh electron density , repels the electron pair of the covalent bond in the hormone molecule .
-THIS MEANS BROMINE JSD SN INDUCED DIPOLE

196
Q

Stage two of halogens

A

On stage 2 , the pair dk electrons in the oi bond of the alkrne are attracted the the positive bromine. . So I’m this case , fhe positive bromine is acting as an rlectropjille .
-sos from pairs now form a covalent bond in the bromine atom now bread and pairs of electrons love onto the otherr bromine atom .
-when a covalent bond breaks like this with both electrons going to the same atom . Scientists call this heteorlyic fission .

197
Q

So at the end of stage 2 , we have carbocation intermediate and a bromine ion

A

…

198
Q

Stage three of halogen

A

In stage three, the electron lair on the bromide ion , are attracted to the positive cadbocn atom in the carbocation intermediate .
/the electron oair Joe forms a covalent bond and we have our final product . Production this case is 1,3 dibromowrhwne .

199
Q

Note in stage three

A

In this reaction , halogen molecule adds across the double bond .
-meaning , two halogen atom end up on the adjacanet carbon atom .
-we cannot get bjt halogen atoms on on the same carbon atoms .

200
Q

One difference between adding a halogen and adding a hydrogen halide

A

Halogen had induced dipole . Hydrogen js life has permanent dipole

201
Q

Second difference adding a halogen and adding a hydrogen halide

A

Makes only one product with asymmetric alkene . Snakes major and minor product with asumemetricnalkene .

202
Q

We can use a halogen to rest for the presecene on unsaturated molecules like alkenes and to do so we us ebromine water

A

Check if it’s unsaturated add drops of bromine water and gently shake the rest tube .
If our substance is usbtwurated then the bromine will add across the double bond and product of reaction will be colourless .
If saturated the bromine water can’t react and remain orange .

203
Q

Electro hill Iv addition of addition of water to alkenes tk make alcohols

A

Scientists call this a hydration reaction
SHEIN hydration reaction of ethene .
- in hydration , the water is in the form of steam and phosphoric acid is used as a catalysts .
The temperature js 300 degrees and the pressure ejs about 6p atmospheres

204
Q

Hydration of alkenes mechanism stage one

A

Catalyst for this reaction. Js phosphoric acid .
Structure shown
Soho’s rich acid has 3 hydrogen atoms each handed to oxygen .
/As we have seen , oxygen is a strongly electronegative element . Meaning phosphoric acid is a polar molecule .
-oxygen atoms ahve a partial negative chathe and the hydrogen atoms have a partial positive chathe .

205
Q

Stage one mechanism (hydration of alkenes)

A

The pair of electrons I. The pi bond of the ethene of are attracted to one of the positive hydrogen atoms in the phosphoric acid .
-in this case , the positive hydrogen atoms act as an relectropjille .

206
Q

Stage one of

A
207
Q

Stage one of hydration of alkenes mechanism part two

A

-now fhe paid dk electrons in the oi bond form a covalent bond to the hydrogen atoms
-at the same time , in the covalent bond between the hydrogen and oxygen breaks .
-the pair of electrons Joe move complete on to the digger Aron .
As we have seen in stage one we have a fabrication intemvolule with a podi r carbon ion and a dihydrogen phosphate ion with a negative oxygen ion .

208
Q

Key is that the pjsosphoric acid is a catalyst

A

Meaning we need to regenerate the phosphoric acid in a layer stage. .

209
Q

Stage two of the hydration of alkenes

A

The carbocations intermediate reacts with a molecule of water. , in the form of steam .
Rememeber that the oxygen atoms in the water meolcules have two loke pairs of electrons .
-of these lone pairs now form a covalent bond between the oxygen and the positive carbon atom I the carbon stink intel’s .

-at the end of season2 , we now have an intermediate molecule containing a positive oxygen atom . this oxygen is positive bevause it’s lone pair of electrons have formed a coal net bond .

210
Q

Stage thee of hdtdrstikn kf alkenes

A

Final stage , involves a hydrogen phosphate ion , we made earlier , the hydrogen ojsoapjge ion forms a cola net bond to snyfrigen in the intermediate disks.
-at the same time the covalent bond in the intermolecular now breaks this is herotic fission z
And now a pair of elections in the home joenkove coklerly into the thay xx
Now we have made our profit ethanol and rheenrated our phosphoric acid catalyst. .

211
Q

As we have send the hydration of ethene produce ethanol .

A

What about asysyemtic sleekness slimempropene xx
How do we detmeine what carbon atom will bond to the hydrogen atom of the wnd which to neenejje

Hydrogen atoms likeee idek aahruh chekc gmthatbcudeo idk what I’m suaing .

212
Q

How alkenes react which hydrogen gas

A

This reaction is called hdyirgenarikn

213
Q

Key points about hydrogenation

A

Hydrogen Melodie’s add across the double bone .
/ so when hydrogen jokes srionnwlekensbeucubisbabuhsatueated keolcue we make an alkane which is SAIT aree .

214
Q

Reaction for hydrogenation

A

Also requires a solid catalyst liek nciken .
Unlike other reactions in alkenes , hydrogenation does not take place by electro Philip reaction .

215
Q

Use of hydrogen work. Js to make margarine

A

Margarine js made by the hydrogenation of vegetable oils .

216
Q

Molecules in the vegetable oils contain fatty acids, and these fatty acids are unsaturated molecules containing one double bond.

A

Unsaturated fatty acids have one double bond which is why vegetable oil has had no boiling point by hydrogenation. We increase the most important which converts from a liquid into like a solid. However, the conditions are controlled so hydrogenation only passed your cars so early. Sunil is the double ones are hydrogenated to increase the melting point.

217
Q

olymers ar used extensively in products

A

polymers can be divdied into two large categroies
-addition
-condensation

218
Q

Key ; polymers are large molecules

A

we form polymers by joining togetheer the ends of small identical molecules called monomers .
-when we form addition polymers the monomers aare alkanes .
-EXAMPLES ethene forming an addition polymer - youneed high temperature and high pressure as well as a CATLAS . then you form poly(ethene )

218
Q

polymerism requires high temprature and presure as wella s catalsysts

A

When alkenes form a polhymer —> double bond in the alkenes oppen up and join one moenemer to another ,
-KEY ; polymer is formed sorry maed by using word poly named by the monomer next in brackets .
-POLYETHENE is used to make plastic bags and bottles .

219
Q

the porduct polymer has no double bonds in the carbon double bond .
-yeah

A

this means that despite being formed from a

220
Q

Addition polymer contains a large number of carbon hydrogen and carbon carbon double bonds .

A

These bonds are both non ppl are are really strong making them
Difficult to break .
-due to this , addition polymers are unregistered to Molecules .
-this lack of rescifocru , means that addition polymers can exist in the environment for a very long time .

221
Q

People ask about the ende of polymer molecules

A

Appears rhat carbon only has three covalent bonds .
-need to remember during polymerisation , other molecules are added to up the ends of the polymer chain .

222
Q

Instead , scientists foren show the repeating units instead of the whole chain. .

A

Repeating units show the arrangement of works that are repeated in the polymer chain.

223
Q

To identify the repeating unit . We take two adjacent carbon atoms on the main chain

A

Then we draw two faebon atoms plus the hydrogen atoms above and poolroom .
-draw the square brackets around .
We then draw the covalent bonds coming from each of the two carbon atoms , extending through the square brackets .

224
Q

-we also need to show many repeating units present in the polymer .

A

The polymer . I am showing has 14 in geh chain for example .
So we need to put a number 7(9; example to represent the repeating units .

225
Q

Check the sheet to see how polymers in a reacfion can be represented as

A

If we know the structure of a polymer . We can workoit thenpolymer
Monomer has a double bond but the repeating u tk does not

226
Q

Addition polymers are made from alkanes which are produced from crude oil

A

We saw that addition polymers are very jnreavtive molecules . That js because the carbon hydrogen and carbon carbon double bonds .
-are both non polar and relatively strong . This makes the bonds difficult tk break .

227
Q

The lack of receiving is one of the reasonably why addition polymers are such useful molecules

A

Addition polymers to make containers for food and drinks without the polymer reacting with don what

228
Q

However , their lack of reactivity is one of the reasons which presents environmental impacts

A

Additions are non biodegradable .
This means , they are not broken down by microorganisms in the environment . Because of this , sdditioknpolymers can pollute the environment receded in .
This can be extremely harmful to wildlife -s.g sea birds can be entangled in polymers mehejnlpokojgnfot food . This can be fatal

229
Q

Even when addition polymers are used repsosnodmlg
, they still involve the use of crude oil which is a non renewable resource

A

The crude oil needs to be transported and refined which requires energy .

230
Q

Because addiifon polymers are used jn such large amounts they can occupy lots of space jnlandfills

A

As you can see , manufactures and dispose of
Addition polymers xan have major effects on the environment

231
Q

There ways to reduce the effects

A

1.firstly , rather than sending waste polymers to landfills they can be combusted , generating energy .
2.hwieger , combusting polymers can release harmful chemicals .

232
Q

What is PVC

A

Polychloroerjsne PVC contains chlorine worms when combusted the gas hydrogen chloride is produced .
-hydrogen chloride is corrosive and must be removed from any waste gases before they are release .

233
Q

Polymer wars can be sorted into the different poly

A

Polymers wast can be sorted into different and recycled into new products .
By recycling polymers we can reduce use of crude oils and amount of work in landfills
. .

234
Q

Another type of eexulox
Kms
Called
Feedstocks cycling .

A

In feedstock replying , waste polymers are converted back to simple hydrocarbons FHESE hydrocarbons can be cracked and conveyed into different polymers .
ADVANTAGE- waste polymers do not need sorting .
Feedstock trucking allows us to finger one polymer into a different polymers

235
Q

Scientists are working on producing new polymers fhag are biodegradable .

A

They are usually based on billogciak mass plants
Benefit of thee elllyners did they naturally break due to the ACGION of kicrograjossm . They seldom
Manufacture form oak t materials as renebwske resource

236
Q

HOWBEER

A

BIodherabslen addition polymers .
-science are also working on oil base dooleyenrrs slowing broken down in sunlight called motogrwdwbkenpolyners .

237
Q
A
238
Q
A
239
Q

Aliphatic hydrocarbon

A

In which the carbon atoms are joined together in Tibet striaght unbrandhed chains or benched chains

240
Q

Aliphatic hydrocarbon

A

In which the carbon atoms are joined together in Tibet striaght unbrandhed chains or benched chains

241
Q

Aliciykic hydrocerbons

A

In which carbon atoms are joined together in a ring structure but are not aromatic

242
Q

Aromatic hydrocarbons

A

In which there is at least one benzene ring in the sturdier

243
Q

Check page 167 make sure u know all the functional groups

A

…

244
Q

How to work out elpeifslnforkulanusijg mass of each element

A

Chekc page 169

245
Q

Why are aromatic hydrocarbons stable ?

A

They are very stable because the electrons are shared across all the carbon atoms this part of the leaflike is hel take yingogle dijnsjubfrukcislnreacitons and often represented used skeletal formula .

246
Q

How to calculate molecular formula using emotional formula

A

Check page 169

247
Q

What is homolyriv fission

A

When a coslne thing breaks and each electron goes to a different bonded atom .
This generates two highly reactive neutral specials called facials , radicals have one or more unpaired electrons shows as dots

Chlorine molecule Yh light .

248
Q

Heeroektic fission what is jt

A

When a covalent thing breaks and hotje leftrokengontonojenofbthebhojdedbsorksntuisbreiskrsbijbabosituhevgwriojnajdbajuojnheijtnrorkee

Broski stuff hrokopsjenjasnandiple

249
Q

Check page 186 learn

A

Table injti

250
Q

Check page 190-191

A

A-level CHEMISTRY (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions