Organic Chemistry Flashcards
1
Q
What can fermentation of sugar produce?
A
AN AQUEOUS SOLUTION (dissolved in water) OF ETHANOL CAN BE PRODUCED by the fermentation of sugar, a renewable source
2
Q
What is the word equation for the fermentation of sugar?
A
Sugar —- Ethanol + Carbon dioxide
3
Q
What does aqueous mean?
A
Dissolved in water
4
Q
What is the homologous series?
A
●Family of hydrocarbons with similar chemical properties, share the same general formula, same functional group and all react in a similar way
5
Q
What is the general formula for alkanes?
A
CnH2n+2
6
Q
Give the first 4 examples of the alkanes?
A
Methane CH4
Ethane C2 H6
Propane C3 H8
Butane C4 H10
7
Q
What is the general formula for alkenes?
A
CnH2n
8
Q
What is the functional group of alkenes?
A
C double bond C
9
Q
Give some examples of alkenes?
A
Ethene C2 H4
Propene C3 H6
Butene C4H8
10
Q
What is the general formula for alchols?
A
CnH(2n+1)OH
11
Q
What is the functional group of alchols?
A
-OH Hydroxyl
12
Q
Name the first four alchols?
A
Methanol CH3 OH
Ethanol C2 H5 OH
Propranol C3 H7 OH
Butanol C4 H9 OH
13
Q
What is the general formula of carboxylic acids?
A
CnH(2n+1)COOH
14
Q
What is the functional group of carboxylic acids?
A
-COOH Carboxyl
15
Q
Name the first 4 carboxylic acids?
A
Methanoic acid HCOOH
Ethanoic acid CH3COOH
Propanoic acid C2H5COOH
Butanoic acid C3H7COOH
16
Q
What is the functional group of esters?
A
COO-
17
Q
Name the 3 esters?
A
Methyl propanoate
Ethyl ethanoate
Butyl methanoate
18
Q
What is the functional group?
A
The part of a molecule that gives its characteristic properties
19
Q
What temperature works best for yeast?
A
25-50 degrees Celsius
20
Q
What happens if the temperature is too high or low for the yeast?
A
Too low = yeast becomes inactive, reaction rate slows
Too high = yeast is denatured, stops working
21
Q
What is an alchol?
A
Carbon based molecule that contain the functional group hydroxyl (-OH)
22
Q
Describe alchols?
A
●Dissolve in water to form neutral solutions
●React with sodium to produce hydrogen
●Burn in air to produce carbon dioxide and water
●Used as fuels and solvents
23
Q
How can ethanol be oxidised to ethanoic acid?
A
By chemical oxidising agents (chlorine, oxygen, halogens) or by the action of bacteria in the air
24
Q
What is the main acid in vinegar?
A
Ethanoic acid
25
What are carboxylic acids?
An organic compound (anything that contains carbon)
26
Describe carboxylic acids?
♧Dissolve in water to form acidic solutions
♧React with carbonates (like sodium carbonate) to produce carbon dioxide
♧React with alchols (in the presence of an acid catalyst) to form esters
♧Don't fully ionise (dissociate) in water so called a weak acid
27
Describe esters?
■Alchols and carboxylic acids reacts together to form esters
■Esters contain the functional group-COO
■Ethanol + ethanoic acid = ethyl ethanoate, an ester
■ Esters are volatile ( have low boiling points)
■Have distinctive smells, used in perfumes and food flavourings
28
Amino acids have two different functional groups, show this for glycine?
Amine group=H2N
Carboxylic group= COOH
Hydrogen and carbon = CH2
Glycine structural formula= H2NCH2COOH
29
What is thermosoftening ploymers?
●Consist of individual polymer chains that are tangled together ( like Spaghetti)
●Weak intermolecular forces so have low BP
●Soften when heated so can be melted and reshaped/remoulded
30
What are thermosetting polymers?
●Consist of polymer chains joined together by cross links
●Don't melt when heated
●Example is melamine
31
In addition polymerisation how many atoms are there?
Repeating unit and the monomer units contain the same amount of atoms
32
Give an example of a thermosoftener?
Poly(ethene)
33
What is addition polymerisation?
When many monomers join together to form a large molecule
34
What affects the properties of polymers?
#What it was made from (i.e what monomer was used)
#The conditions (for example temperature and catalyst) under which it was made
35
The properties of polymers depends on differdng reactions used, give an example where this can be seen?
Low density poly(ethene), LDPE and high density poly(ethene) , HDPE are both made from the monomer ethene but have different properties due to the different reactions used to make them. LDPE= Carrier bags. HDPE=plastic bottles
36
Describe starch and cellulose?
●Starch and cellulose are polymers of sugars
●Made by plants, important for life
●Sugar, starch and cellulose are carbohydrates
●Glucose molecules join to form starch molecules
37
What is bromine water used for?
●Alkenes more reactive than alkanes
●Alkenes react when shaken with bromine water
●Turns from orange to colourless
●Used to differentiate between alkenes and alkanes
38
What causes global dimming?
Solid particles, which reduce the amount of sunlight reaching the earth
39
What are the conditions needed for steam cracking?
●High temperatures
●Steam
40
What does cracking make?
●Hydrocarbons called alkenes (like ethene)
●Alkenes have double covalent bonds between two carbon atoms
41
How are plastics made?
Materials named plastics are all synthetic (man made) polymers made by the process of addition polymerisation
42
What are the compounds in crude oil?
Compounds in crude oil are HYDROCARBONS (molecules made of only carbon and hydrogen atoms)
43
What are alkanes?
Carbon atoms, linked to 4 other atoms by single bonds
44
What is thd chemical equation for complete combustion, burning with plenty of oxygen?
C + O2 --------> CO2
45
What is the chemical symbol equation for incomplete combustion, burning with limited oxygen?
2C + O2 --------> 2CO (carbon monoxide)
46
What lethal chemical is produced by burning with limited oxygen?
Carbon monoxide, 2CO
And particulate carbon also know as soot
47
Due to high temperatures when burning fuels, nitrogen in air reacts with what?
Oxygen to form nitrogen oxides
48
Why are nitrogen oxides bad for people and the environment?
People= respiratory problems
Environment= nitrogen oxides react with water to form acid rain which damaged plants and buildings
49
What does it mean if the system is closed?
No reactants are added and no products are removed
50
How is equilibrium achieved?
When rate of the forward reaction is equal to the rate of the backward reaction
51
What do chemicals in cells make when they react together?
Release electricity
52
What is combustion?
Burning of hydrocarbon fuels
53
What happens during combustion?
Carbon and hydrogen are oxidised, energy is released, waste products are released into the atmosphere (carbon monoxide, solid particles)
54
What are the problems with incomplete combustion?
●Carbon dioxide is a poisonous gas which binds to haemoglobin in red blood cells preventing them from carrying oxygen to your body, no smell or colour so don't realise
●Particulate carbonncauses health problems, irritates lining of lungs, cause asthma and causes global diming which can reduce rainfall
55
What is global dimming?
Reduced amount of sunlight reaching the earth because of atmospheric particulate (carbon particulate)
56
What is fractional distillation?
Crude oil is heated until it evaporates, vapour moves up a fractionated column, top is colder where shorter hydrocarbon molecules condense and are collected, longer hydrocarbon molecules condense at high temperatures and are collected at the bottom
57
Why is there a high demand for shorter chain alkanes?
Release energy more quickly, so more demand for them as fuels (examples are methane and ethane)
58
What happens during catalytic cracking?
●Hydrocarbons heated until vaporise
●Vapour is passed over a hot catalyst
●Thermal decomposition
●Products are alkanes and alkenes
59
What is the rule for hydrogen and carbon?
●Hydrogen (H) (-H) atoms can only make 1 bond each
|
●Carbon (C) (- C - ) can make 4 bonds. |
60
What are alkenes used for?
Used to make a range of new compounds like polymers and industrial alchol (used to make things)
61
Is crude oil a finite or infinite resource?
A finite (non renewable) resource, used to produce fuels and other chemicals
62
What are the properties of large Hydrocarbons?
●More viscous it is (thick)
●Higher boiling point
●Less volatile (don't evaporate easily)
●Ignites less easily
63
How is crude oil separated?
Crude oil is separated into different fractions (parts) by fractional distillation
64
What is a hydrocarbon?
Molecules made of only carbon and hydrogen
65
Why do we need to crack Hydrocarbons?
Longer chain Hydrocarbons can be broken down into shorter, more useful Hydrocarbons, called cracking
66
Are alkanes reactive and how well do they burn?
Alkanes are fairly unreactive but burn well
67
Which is more reactive alkenes or alkanes?
Alkenes due to the double carbon bond (C=C)
68
What does complete combustion of ethanol produce?
Carbon dioxide and water
69
What is crude oil from?
FOSSILISED REMAINS OF PLANKTON, found in earth's crust, non-renewable
70
Why do hydrocarbon properties vary?
Due to the varied sizes which affects their properties and how they can be used
71
Describe the features of a larger hydrocarbon?
●Less easily it flows
●Higher boiling point
●Less easily it ignites
72
What are fuel cells?
Very efficient way of producing electrical energy.
73
What are the advantages of fuel cells?
Hydrogen fuel cells produce water (non polluting), lightweight, small, no moving parts so unlikely to break down
74
What are alkenes useful for making?
●Because alkenes are unsaturated (at least one double carbon bond), they are useful for making other molecules especially polymers (long chain molecules)
75
Give an example of addition polymerisation?
Monomers (small molecules with double bonds) can join together to form polymers, addition polymerisation
76
Describe carboxylic acids?
●dissolve in water to form acidic solutions
●React with carbonates (like sodium carbonate) to produce carbon dioxide
●React with alchols (in the presence of an acid catalyst) to form esters
●Don't ionise (dissociate) fully in water = weak acid
77
What happens to ethene monomers in polymerisation?
●Ethene monomers are unsaturated (contain double carbon bonds C=C) ------>
●Poly(ethene) polymer are saturated as the double bond opens to form them
78
Why are Hydrocarbons able to make further bonds?
Because they have double bonds/unsaturated
79
What are the conditions needed for catalytic cracking?
●High temperatures
●Catalyst (Speed it up)
80
Why are alkenes very useful?
●Used to make chemicals called polymers
●used as a starting material for other useful chemicals
●More reactive than alkanes
81
Define thermal decomposition?
A chemical reaction that happens when a compound breaks down when heated
82
Are alkenes saturated or unsaturated?
Alkenes are unsaturated hydrocarbons
83
What is the chemical formula for butane?
C4H10
Always the rule:
H-has one bond
C - has 4 bonds
84
What do fuels contain?
Most fuels are compounds of carbon and hydrogen, msy contain sulfur
85
What is the chemical formula for propane?
C3H8
86
What is the chemical formula for ethane?
C2H6
87
Hydrocarbons can be saturated and unsaturated, what does that mean?
Saturated=only contain single bonds
Unsaturated=at least one double bond C=C
88
Where are most Hydrocarbons obtained from?
Obtained from alkanes in fractional distillation
89
What is the formula for propane?
C3H6
90
What are the features of long chain Hydrocarbons?
●Has lots of carbon atoms
●Not very flammable
●Doesn't make good fuels
91
How are long chain Hydrocarbons converted into shorter chain, more useful Hydrocarbons?
Process called cracking
92
What happens in cracking?
A long chain alkane is broken down (cracked) to produce smaller, shorter chain, useful molecules (alkane and alkene)
93
Balance this cracking equation
C25H52 ----> C20H42 + C?H?
Number of carbon and hydrogen atoms need to be the same on both sides of the equation.
C5H10. 20 + 5 = C25
42 + 10 = H52
94
Which is more reactive alkenes or alkanes?
ALKENES so we use alkanes to test for alkenes, bromine water test as
Bromine water + alkane=nochange
Bromine water + alkene=colouress
95
Do alkanes have single or double bonds?
Have SINGLE COVALENT BONDS BETWEEN ATOMS
96
Describe alkenes in terms of carbon bonds?
●Carbon atoms form double bonds
●Not all carbon atoms have to be linked to 4 other atoms because a double bond(=) represents 2 bonds
97
Chemical formula for butene?
Butene C4H8
98
What happens during combustion (burning) of hydrocarbon fuels?
●Carbon and hydrogen are oxidised (gain/ combines of oxygen)
●Energy is released
●Waste products produced and released
99
The products of cracking are useful as fuels as there is a high demand for fuels with small chains of carbon atoms, why?
Easy to ignite, produce energy quickly, low boiling point
100
What happens during steam cracking?
Hydrocarbons are mixed with steam and heated to a high temperature
101
When is sulfur removed from fuels?
Sulfur can be removed from fuels before burning (in motor vehicles) and removed from the waste gases after combustion (in power stations)
102
Why do alkenes react with oxygen in combustion and produce smoker flames?
Burn smokier flames than alkanes due to incomplete combustion
103
What is the chemical formula of ethene?
C2H4
104
Are alkenes saturated or unsaturated?
Have atleast one double bond so unsaturated. (To remember there is e n e in alkene which resembles the C=C double bond)
105
What are the 2 ways of cracking?
♡Catalytic cracking
♡Steam cracking
106
Describe DNA?
●Very large molecule
●Made from two polymer chains
●Essential for life as stores and transmits instructions for development of living organisms
107
What does DNA stand for?
Deoxyribonucleic acid
108
Dna is made from two polymer chains, constructed of four different nucleotides. Name them?
Cytosine (C) + Guanine (G)
Adenine (A) + Thymine (T)
109
What do the two polymer chains form in DNA?
Double helix structure
110
What do alchols and carboxylic acids reacts to form?
Esters
111
What functional group do esters contain?
-COO
112
What does ethanol + ethanoic acid create?
Ethyl ethanoate, an ester
113
Why are esters used in perfumes and as food flavourings?
Have distinctive smells
114
Esters are volatile, what does volatile mean?
Have a low boiling point
115
Alchols dissolve in water to form a alkaline, neutral or acidic solution?
Neutral solution
116
What reacts with sodium to produce hydrogen?
Alchols
117
Alchols burn in air to produce what?
Carbon dioxide + water
118
What burns in air to produce carbon dioxide and water?
Alchol
119
What are alchols used as?
Fuels and solvents
120
What is the chemical formula of methane?
CH4
121
What does a single line between atoms show in alkanes?
A single covalent bond
122
How can ethanol (alchol) be produced?
By reacting ethene with steam when a catalyst (phosphoric acid) is present
123
What happens when hydrogen us added to alkenes?
Produces alkanes, a nickel catalyst is used
124
What is the difference between alkanes and alkenes?
Alkane Alkene
●Saturated ● Unsaturated
●Carbon atoms ●Not all carbon
linked to 4 other atoms have to
atoms be linked to 4
●Less reactive ●More reactive
●CnH2n+2 ●CnH2n
●Single bonds ●Double bond
125
What happens in an addition reaction?
Two or more molecules combine to form a larger molecule, no loss of atoms, in organic chemistry it involves unsaturated reacting to become saturated
126
Give an example of an addition reaction?
Ethene + Steam ----> Ethanol
C2H4 + H2O -----> C2H5OH
127
What happens to a long chain alkane when it reacts with heat and a catalyst?
Short chain alkane and alkene
128
What happens to a decane (10) when it reacts with heat and a catalyst?
Octane (8) and ethane (2)
