2 - Developing Fuels (DF) Flashcards
1
Q
Prefix for 1 carbon in a hydrocarbon
A
Meth-
2
Q
Prefix for 2 carbons in a hydrocarbon
A
Eth-
3
Q
Prefix for 3 carbons in a hydrocarbon
A
Prop-
4
Q
Prefix for 4 carbons in a hydrocarbon
A
But-
5
Q
Prefix for 5 carbons in a hydrocarbon
A
Pent-
6
Q
Prefix for 6 carbons in a hydrocarbon
A
Hex-
7
Q
Prefix for 7 carbons in a hydrocarbon
A
Sept-
8
Q
Prefix for 8 carbons in a hydrocarbon
A
Oct-
9
Q
Prefix for 9 carbons in a hydrocarbon
A
Non-
10
Q
Prefix for 10 carbons in a hydrocarbon
A
Dec-
11
Q
Suffix for alkanes
A
-ane
12
Q
Suffix for alkenes
A
-ene
13
Q
Prefix for rings
A
Cyclo-
14
Q
Suffix for alcohols
A
-ol
15
Q
Suffix for carboxylic acids
A
-oic acid
16
Q
How to name chain alkane isomers
A
-Find name of longest chain
-Name of side chain
-Find which number of carbon side chain is attached to
17
Q
Name structure of chain alkane isomers
A
Side chains (in alphabetical order), main chain
18
Q
Define general formula
A
Represent any member of a homologous series
19
Q
Define full structural formula
A
Shows all atoms and bonds in the compound
20
Q
Define shortened structural formula
A
Does not show all/any bonds in the compound
e.g. CH3CH(CH3)CH3
21
Q
Define skeletal formula
A
Represents the carbon-carbon bonds in the hydrocarbon
22
Q
Define aromatic
A
Compounds containing one or more benzene rings
23
Q
Define aliphatic
A
Compounds that do not contain benzene rings
24
Q
Define structural isomers
A
Same molecular formula, but atoms are bonded in a different order
25
What are the different types of structural isomers?
-Chain isomer
-Position isomer
-Functional group isomer
26
Define chain isomer
Different lengths and branch positions
27
Define position isomer
Functional groups attached to different carbons
28
Define functional group isomer
Molecule has different functional groups
29
Define stereoisomer
Same molecular formula and structural formula but atoms are arranged differently in space
30
What are the different types of stereoisomers?
-Geometric isomers
-E/Z isomers
-Optical isomers
31
Define E/Z isomer
Molecule with a C=C bond that cannot rotate with different atoms attached to each carbon
Can also be called trans/cis isomers
32
Define optical isomer
Due to attachment of 4 different atoms/groups around a carbon atom
33
Define cracking
Process of taking longer hydrocarbons and breaking them into smaller (more useful) ones
34
What can hydrocarbons be cracked with?
-Steam and high pressure
-Aluminium oxide (catalyst) and high temperatures
35
What does geometric isomerism require?
-No rotation around C=C double bond
-Different atoms/groups attached to C=C
36
Define standard state
Physical state of a substance under standard conditions
37
What are the standard conditions?
-Pressure: 101kPa
-Temperature: 298K
-Reactions with aqueous solutions:
1 mol dm^-3
38
Define enthalpy change of combustion (ΔHcθ)
Energy required for 1 mile of a substance to completely combust under standard conditions
39
How can ΔHcθ be measured?
q=mcΔT
40
Define enthalpy change of reaction (ΔHrθ)
Molar quantities of reactants stayed in the equation react under standard conditions with reactants and products in standard states
41
Assumptions for ΔHrθ
-Treat all specific heat capacities as water (4.18)
-Assume densities of all solutions as the density of water
-Reaction goes to completion with no other reactions occurring
42
Equation for bond enthalpy
ΔH = ΣEnthalpy of bonds broken - ΣEnthalpy of bonds made
43
Qualities of endothermic reactions
-Bonds made
-Requires energy
Positive ΔH
44
Qualities of exothermic reactions
-Bonds broken
-Releases energy
-Negative ΔH
45
Define average bond enthalpy
Since bonds of the same type do not have the same amount of energy the average of energy for all bonds taken
46
What does a shorter bond mean for bond enthalpy?
Higher bond enthalpy
47
What does a high electron density mean for bond enthalpy?
Higher bond enthalpy - shorter bond
48
Define enthalpy change of neutralisation (ΔHneutθ)
Enthalpy change that occurs when 1 mole of hydrogen ions react with 1 mole of hydroxide ions to form 1 mole of water under standard conditions in a solution with concentration 1 mol dm^-3
49
How can a single bond be represented?
σ-bond
(sigma bond)
50
How can a double bond be represented?
π-bond
(pi bond)
51
How to count number of σ-bonds?
Count every single bond, as well as one of the double bonds
52
How to count number of π-bonds?
Number of double bonds in molecule
53
Define electronegativity
Measure of the attraction of the atoms in a covalent bond for the electrons in the bond
54
How does electronegativity vary across the period table?
Increases across periods and up a group
55
Define dipole
Bonds between elements (apart from C & H)
56
If the element is more electronegative then the dipole is…
Negative (δ-)
57
If the element is less electronegative then the dipole is…
Positive (δ+)
58
If the elements are the same then the dipole is…
None
59
Define electrophile
Electron pair acceptor
60
What does the arrow represent in electrophilic addition mechanisms?
Shows the moment of a pair of electrons in the mechanism
61
Define heterolytic fission
Where both electrons in a covalent bond remain with one atom during bond breaking
62
Define carbocation
Intermediate formed during electrophilic addition, where an organic molecule has a positively charged carbon atom
63
In electrophilic addition mechanisms, what product forms if a reactant is a halogen?
Dihalogen alkane
64
In electrophilic addition mechanisms, what conditions if a reactant is a halogen?
None specific
65
In electrophilic addition mechanisms, what product forms if a reactant is water?
Alcohol
66
In electrophilic addition mechanisms, what conditions are needed if a reactant is water?
-Phosphoric acid
-High temperature
-High pressure
67
In electrophilic addition mechanisms, what product forms if a reactant is a hydrogen-halide?
Halogenalkane
68
In electrophilic addition mechanisms, what conditions are needed if a reactant is a halogen?
None specific
69
In electrophilic addition mechanisms, what product forms if a reactant is hydrogen?
Alkane
70
In electrophilic addition mechanisms, what conditions are needed if a reactant is hydrogen?
-Nickel catalyst
-60°C
-High pressure
71
What must be on a electrophilic addition mechanism diagram?
-Full charges
-Partial charges (δ+, δ-)
-Arrow start and ends
72
What does the strength of intermolecular forces determine?
Physical properties of organic compounds (mp/bp)
73
What are the types of intermolecular forces?
-Instantaneous-induced dipole
(/van de Waal’s forces)
-Permanent-permanent dipole
-Hydrogen bonding
74
Define instantaneous-induced dipole forces
Because electron position can constantly change if all electrons are on one side of the atom (which rises a dipole) induces dipoles on nearby atoms
Example: halogens
75
Define permanent-permanent dipole forces
Attraction between δ+ of a molecule and δ- of a neighbouring molecule
(NOT C-H)
76
Define hydrogen bond forces
Attraction between lone pairs of electrons of a very electronegative atom and a hydrogen atom in a neighbouring molecule
77
Define Hess’ law
Total enthalpy change of a reaction is independent of the route taken, as long as the initial and final conditions are the same for each route
78
What circumstances lead to enthalpy change not possible to measure?
-Slow rate of reaction
-High activation energy
-More than one reaction takes place
79
Rules of Hess’ law
-Write down equation for enthalpy change being found
-Use other information given to make a cycle (usually triangle)
-Apply Hess’s law, go with the flow of arrows
80
Define enthalpy change of formation (ΔHfθ)
When 1 mole of a substance is formed from its elements in their standard states
Example: Na(s) + 0.5Cl2(g) -> NaCl(s)
81
If there are more points of contact from molecules what does that do to the boiling point?
Increases it
82
Benefits of fossil fuels
-Efficient
-Reliable
-Has existing infrastructure
83
Risks of fossil fuels
-Non sustainable
-Harmful emissions (CO2, CO, SO2)
NO2 formed at high temps in car engines
84
Benefits of biofuels
-Renewable
-Lower CO2 emissions, some CO2 taken in by plants but not carbon neutral
85
Risks of biofuels
-Land for crops, not food
-CO2 still released (combustion of fuel)
86
Benefits of hydrogen (fuel)
-Produces only water with energy
-Can power internal combustion engine/hydrogen fuel cell
87
Risks of hydrogen (fuel)
-Challenging to store
-How is electricity supplied for electrolysis?
-NO2 still produced in car engines at high temps
88
How to do Hess’ cycle with combustion
-Add O2 to both sides of equation and add products to cycle
-Calculate the enthalpy of reaction for both sides
-Add/subtract following the arrow
89
How to do Hess’ cycle with formation
-Add the substances needed to the cycle (given as info)
-Balance
-Calculate
-Add/subtract following arrow
90
How to do Hess’ cycle with bond enthalpies
-Add the substances needed to the cycle (given as info)
-Balance
-Calculate
-Add/subtract following arrow
91
Impact of CO2 to environment
-Greenhouse effect
92
How to reduce CO2
-Biofuels
93
Impact of CO to environment
-Toxic
94
How to reduce CO
-Reacts in catalytic converter
95
Impact of NOx to environment
-Photochemical smog
-Tropospheric ozone
96
How to reduce NOx
-Reacts in catalytic converter
97
Impact of SOx to environment
-Acid rain
98
How to reduce SOx
-Sulfur removed from fossil fuels before being burnt
99
Define catalyst poison
Chemicals bind very strongly to catalyst, covering surface
100
What happens if catalyst binds too weakly?
Chemicals do not stay long enough to react
101
Define heterogeneous
Catalyst is in a different state from the reactants and products
102
Define catalyst
Increases rate of reaction by lowering activation energy and is not used up
103
1st step of heterogeneous catalyst
Reactants adsorb onto catalyst surface
104
2nd step in heterogeneous catalyst
Bonds in reactants weaken and break (bonds being pulled further apart)
105
3rd step in heterogeneous catalyst
Bonds in products form
106
4th step in heterogeneous catalyst
Products desorb from catalyst surface
107
Examples of heterogeneous catalysts?
-Catalytic converter
-Al2O3 (cracking)
-Fe (Haber process)
108
Examples of heterogeneous catalysts?
-Catalytic converter
-Al2O3 (cracking)
-Fe (Haber process)
109
What can the catalyst surface for a catalytic converter be?
Pt/Rh/Pd
110
When are stereoisomers not called E/Z isomers?
When there are not 2 hydrogens
