Organic chemistry (spec) Flashcards
1
Q
what is crude oil
A
a finite recourse found in rocks
2
Q
crude oil is the remains of….
3 points
A
an ancient biomass
mainly plankton
that was buried in the mud
3
Q
crude oil is a mixture of what
A
crude oil is a mixture of hydrocarbon molecules
4
Q
what are hydrocarbons
A
molecules made up of hydrogen and carbon atoms ONLY
5
Q
general formula of alkanes
A
Cn H2n+2
6
Q
first 5 alkanes
A
methane
ethane
propane
butane
pentane
7
Q
functional group of alkanes
A
there is none
8
Q
why are alkanes said to be saturated
A
the carbon atoms are all fully bonded to hydrogen atoms
9
Q
what are most of the hydrocarbons in crude oil called
A
alkanes
10
Q
what can crude oil be used to produce
x4
A
plastic
petrol
pharmaceuticals
cosmetics
11
Q
what does viscosity mean
A
the thickness of a fluid
12
Q
what happens to visosity as the size of the hydrocarbon increases
A
the larger the hydrocarbon, the higher the viscosity
( flow slowly)
13
Q
what does flammability tell us
A
how easily a hydrocarbon combusts
14
Q
what happens to flammability as the size of hydrocarbon increseases
A
the larger the hydrocarbon, the lower the flammability
15
Q
what can you say about flammability of long chain hydrocarbons
A
long chain hydrocarbons are very difficult to burn
16
Q
what hydrocarbon is used in a bunsen burner. what does this show
A
methane is used in a bunsen burner
show short chain hydrocarbons are very flammable
17
Q
what is boiling point
A
the temperature at which a liquid turns into a gas
18
Q
at room temp, what is the state of the first four alkanes.
what does this show
A
gas
shows that short chain hydrocarbons have low boiling points
19
Q
what are the boiling points of the first 4 alkanes (general)
A
lower than room temp
20
Q
what happens to bp as the size of the hydrocarbon molecule increases
A
boiling point increases as size of hydrocarbon increases
21
Q
what does the flammability, boiling point, and viscosity of hydrocarbons influence
A
boiling point, viscosity and flammability
influence how hydrocarbons are used as fuels.
22
Q
when do hydrocarbon fuels release energy
A
hydrocarbon fuels release energy when COMBUSTED (burned)
23
Q
during combustion of hydrocarbons,
what happens to the hydrogen and carbon atoms
A
the hydrogen and carbon atoms react with o2
THEY ARE OXIDISED
24
Q
word equation for complete combustion of alkanes
A
hydrocarbon + oxygen = carbon dioxide + water
25
balance the following equation (complete combustion of methane)
CH4 + O2 = CO2 + H2O
first balance carbons
(already balanced)
then balance Hydrogen
4 in reactants
2 in products
- times products Hydrogen by 2
put large 2 infront of H2O
now balance Oxygen
2 in reactants
4 in products (because u added 2 infront of H2O)
put large 2 infront of reactants O2
=
CH4 + 2 O2 = CO2 + 2 H2O
26
fir the hydrocarbons in crude oil to be useful, what must we do first
separate them using fractional distillation
27
what happens through fractional distillation (brief)
2 points
crude oil is separated into fractions
fractions contain hydrocarbons with similar carbon number
28
process of fractional distillation
7 points
. crude oil is vaporised ( turned into gas by heating)
. the hydrocarbon gases enter the column
. column is hotter at bottom, cooler at top
. hydrocarbon gases rise up column
. as hydrocarbon gases rise up column, they cool down
. when hydrocarbons reach their boiling point in the column they condense (to liquid)
. hydrocarbon fractions then removed
29
where are the long chain hydrocarbons removed in the fractional column
explain why
at the bottom of the column
think of it like this :
long chain hydrocarbons have super high b.p
even at the bottom of the column, it's not hot enough to keep these hydrocarbons as gases.
therefore they condense and can be collected
30
what happens to very short chain hydrocarbons in the fractional column
explain why
they are removed from the top of the column, still as gases
think of it like this:
.short chain hydrocarbons have really low boiling points
.all throughout the column, the temperature is hot enough to keep these as gases.
.and so they cannot condense and are taken out from the top still in gas form
31
name 5 products of fractional distillation that are used as fuels
ppk dh !
petrol,
diesel,
kerosene,
heavy fuel oil and
liquefied petroleum gases
32
what does feedstock mean
a chemical used to make other chemicals
33
the fractions can be processed to make feedstock
Feedstocks are used by the petrochemical industry to make things like:
solvents
lubricants
detergents
polymers
34
2 key features of alkanes
. their general formula CnH2n+2
. only single covalent bonds between atoms
35
why do long chain hydrocarbons NOT make good fuels
they are not very flammable
36
what is cracking used for.
Hydrocarbons broken down (cracked) to produce smaller,
more useful molecules
37
what is created from cracking a long chain alkane
smaller
alkanes and alkenes
38
2 ways to carry out cracking
catalytic cracking
steam cracking
39
summarise process of catalytic cracking
vaporise the hydrocarbons through high temp
then pass them over a hot catalyst ( to speed up reaction)
40
summarise process of steam cracking
mix the hydrocarbons with steam at a very high temperature
41
why are alkenes useful, what can they be used for
to produce polymers
as a starting material for other chemicals
42
functional group of alkenes
one c=c double bond
43
whats more reactive, alkene or alkane
alkene
44
how to test for alkene
3 steps
.add the molecule to orange .bromine water
shake
. urns colourless if alkene was added
45
balance the following equation
( cracking of a long chain hydrocarbon )
C25 + H52 = C20 + H42 + C...H....
C25 + H52 = C20 + H42 + C5H10
46
general formula of alkenes
CnH2n
47
what does the displayed formula show us
all the atoms and the ecovalent bonds eg
h h
l l
c=c
l l
h h
48
why are alkenes unsaturated
they have 2 less hydrogen atoms
than an alkene with the same carbon number
49
what does functional group mean
the part of a molecule that determines how it reacts
50
how do you know if molecules belong to the same homologous series
they will have the same functional group
51
what is different about the combustion of alkenes as opposed to alkanes
alkenes undergo incomplete comnustion
52
what does combustion of alkenes create
water
carbon dioxide
unburnt carbon particles
53
what do you see with the incomplete combustion of alkenes
they burn in air with a smoky flame
54
what is hydrogenation
when alkenes react with hydrogen
(with a catalyst)
to produce an alkane
55
what conditions are needed for hydrogenation
( alkene reacting with hydrogen to form an alkene)
150 degrees
nickel catalyst
56
how is an alkane created when an alkene reacts with hydrogen
by the addition of atoms across c=c double bond
which splits to form a c-c single bond
57
what is the hydration of an alkene
think about water, getting drunk...
when an alkene is
reacted with steam
to produce an alcohol
(needs high pressure and a catalyst)
58
what conditions are needed for the hydration of alkenes
300 degrees
70 atm
phosphoric acid catalyst
59
what is unique about the hydration of alkenes reaction
it is reversible
to increase yield of ethanol unreacted ethene and steam can be passed back through the catylyst
60
what halogens do alkenes react with
chlorine
bromine
iodine
61
what are the conditions for the reaction of alkenes and halogens
no special conditions
62
word equation for reaction of alkene and halogen
alkene + halogen =
di halogen alkane
where the halogen is one of the following : (iodo, bromo, chloro)
63
why does the reaction of halogens and alkenes form a dihalogenalkane
the halogen atoms add across the double bond
double c=c bond breaks
so no longer an alkene
halogens are diatomic hence (di)
64
important thing to remember about halogens
All of the halogens exist as diatomic molecules
a pair of atoms chemically bonded
65
first 4 alkenes
ethene
propene
buene
pentene
66
functional group of alcohols
O-H
67
what are alcohols used as
fuels
solvents eg
( perfume, mouthwash)
68
what can ethanol be used in
alcoholic drinks
69
structural formula for methanol
( a simplified version that scientists use)
CH3OH
70
structural formula for ethanol
CH3CH2OH
71
structural formula for propanol
CH3CH2CH2OH
72
structural formula for butanol
CH3CH2CH2CH2OH
73
2 ways to make ethanol
hydration of ethene
fermentation of sugar
74
advantage of hydration of ethene to make ethanol
high yeild
75
disadvantage of hydration of ethene to make ethanol
needs a lot of energy
ethene comes from finite crude oil
76
describe process of fermentation of sugar to make ethanol
mix sugar solution with yeast
yeast converts sugar solution to a solution of ethanol (aq)
77
what conditions are needed for the fermentation of sugar to produce ethanol
30 degrees
anaerobic conditions
(without o2)
78
adavantages of using fermentation of sugar to produce ethanol
low temp -not much energy
sugar from plants - renewable
79
disadvantages of using fermentation of sugar to produce ethanol
ethanol produced is dissolved in water (aq)
must then be distilled to get pure ethanol
this distillation requires energy
80
are alcohols soluble in water
yes
81
what type of solutions do alcohols form
alcohols form neutral solutions
82
what happens to solubility of alcohols as the carbon chain increases
as the number of carbon atoms increases, the solubility decreases.
83
word equation for reaction between alcohol and sodium
alcohol + sodium = alkoxide + hydrogen
84
complete the following reaction for ethanol and sodium
ethanol + sodium =
sodium ethoxide + hydrogen
85
what happens when an alcohol reacts with sodium
hydrogen in released
alkoxide is formed
86
what happens when alkoxides are added to water
if alkoxides are added to water they form strongly alkaline solutions
87
what happens when alcohols react with an oxidising agent
they produce a carboxylic acid and water
88
word equation for ethanol and oxidising agent
ethanol= ethanoic acid and water
89
word equation for combustion of alcohols
alcohol + oxygen = carbon dioxide + water
90
what happens when alcohol undergoes combustion
energy is released
91
balance the following combustion equation of ethanol
C(2)H(5)OH + O(2) =
CO(2) + H(2)O
first balance carbons
2 on reactants
1 on products
- so put large 2 infront of CO(2)
now balance hydrogen atoms
6 on reactants
2 on products
- so put large 3 infront of H(2)O
now there are 6 hydrogens on products
lastly balance Oxygen
3 on reactants- C(2)H(5)OH & O(2)
7 on products - 2CO(2) & 3H(2)O
- so as you need 4 more oxygens in reactants put large 2 infront of O(2)
so....
C(2)H(5)OH + 2O(2) =
2CO(2) + 3H(2)O
92
balance C4H9OH + O2 = CO2 + H2O
C4H9OH + 6O2 = 4CO2 + 5H2O
93
what are the 4 reactions of alcohols that you need to learn
sodium
burn in air
added to water
oxidising agent
94
functional group of carboxylic acid
OH-C=O
95
structural / displayed formula for methanoic acid
HCOOH
96
structural / displayed formula for ethanoic acid
CH3COOH
97
structural / displayed formula for propanoic acid
CH3CH2COOH
98
structural / displayed formula for butanoic acid
CH3CH2CH2COOH
99
what happens when carboxylic acids are added in water
they are partially ionised to form weakly acidic solutions
they lose a hydrogen
100
in water what are carboxylic acids
weak acids
101
what is formed when ethanoic acid is dissolved in water
a negative eth(anoate) ion
a positive hydrogen ion
102
why are carboxylic acids weak acids
they only partially ionise in aqueous solution
103
what does it mean when you say carboxylic acids only partially ionise
the carboxylic acid molecules dont all release their hydrogen ions
104
compare ph of carboxylic acids (weak) and strong acids
carboxylic acids have a higher ph than strong acids
eg hydrochloric acid
105
word equation for carboxylic acid + metal carbonate
carboxylic acid + metal carbonate = salt + water +carbon dioxide
106
complete word equation for propanoic acid +potassium carbonate
propanoic acid +potassium carbonate =
potassium propanoate + water + carbon dioxide
107
what is formed from reacting carboxylic acid and alcohol
an ester + water
108
what are esters used in/ why
foods/ perfumes
have a nice smell
109
name an ester and how its made
ethanoic acid+ ethanol= ethyl ethanoate
110
what catalyst is needed to produce ethyl ethanoate
sulfuric acid catalyst
111
is the reaction between a carboxylic acid and alcohol reversible
yes
112
how are carboxylic acids made
by reacting an alcohol and an oxidising agent
113
the reaction of a carboxylic acid dissolved in water is reversible. what does this mean
the ethanoate ion and H+ ion can recombine to a carboxylic acid.
114
what is a monomer
the identical molecules that are added to create a polymer
115
what is an addition polymer
a polymer made up of alkene monomers
116
what is a repeating unit
the short hand way of showing the structure of a polymer is called
117
how are polymers made
by adding together thousands of small identical molecules
118
what are the two types of polymers
addition
condensation
119
do additon polymers have the double c=c bond like its seperate monomers
no
120
how are polymers named
poly,
followed by the name of the
monomer
121
the short hand way of showing the structure of a polymer is called
the repeating unit
122
how do you work out the repeating unit of a polymer
take any two carbon atoms that are next to eachother
draw these with the hydrogens attatched
put in brackets with a small n on the right
123
what should you remember about the atoms in a polymer and its monomer
all the atoms in the monomer end up in the polymer
124
what is the polymer for chloroethene called
poly(chloroethene)
125
how are esters formed
carboxylic acid + alcohol
(sulfuric acid catalyst)
= ester
126
what is meant by a condensation polymer
