Wider Impact Of Chemistry, Organic Molecules and Hydrocarbons Flashcards

1
Q

Chemical process development must consider

A

Social implications (labour, use of land, impact on local amenities) and economic factors (industry plant sitation, transport, availability of services)

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2
Q

Cost of process

A
Research and development
Capitol cost of plant
Depreciation
Labour costs
Raw materials
Energy costs
Waste disposal costs
Safety measures
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3
Q

Environmental factors

A

Impact on environment and energy consumption

“Polluter pays”

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4
Q

Green chemistry, manufacturers must

A

Keep waste to minimum
Use renewable resources if possible
Keep energy costs to a minimum
Catalysts so low temperatures can be used
Non toxic reactants if possible
Waste products treated to give non toxic materials

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5
Q

Alkene formula

A

CnH2n+2

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6
Q

Naming rules

A

Stem (meth, eth, prop….)
Suffix (ane, ene, yl, ol, oic acid, chloro)
Number the carbons from end closest to side chain
Count longest chain of Carbons
Alphabetical order

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7
Q

Alkane formula

A

CnH2n

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8
Q

Alkanes are..

A

Non polar due to tetrahedral shape and difference in electronegativity, they don’t dissolve in water as they can’t form hydrogen bonds, boiling point increases as chain length increases, branching in chain decreases boiling point

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9
Q

How do functional groups affect physical properties?

A

Boiling point affected by intermolecular forces type and strength
Non polar molecules have weak instantaneous dipole-induced dipole forces
Permanent dipole molecules have stronger dipole-dipole forces
N-H/F-H/O-H have hydrogen bonds

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10
Q

Hydrogen bonds in carboxyllic acids create a..

A

Dimer (2 molecules joined together)

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11
Q

Solubility in water for carboxyllic acids and alcohols

A

Highly soluble
Solubility decreases as chain length increases
Water cannot hydrogen bond with long hydrocarbon chains as they are hydrophobic

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12
Q

Structural isomers definition

A

Compounds with same molecular formula but different structural formula

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13
Q

Electrophile definition

A

Electron pair acceptor

Positive ions/positive part of polar molecule

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14
Q

Nucleophile definition

A

Electron pair donor

Negative ions/negative part of polar molecule

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15
Q

Radicals definition

A

Atom/molecule with an impaired electron, very reactive

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16
Q

Heterolytic bond fission

A

Covalent bond breaks, 2 electrons move into just one of the atoms
Results in positive and negative ions
E.g. Cl2–>Cl+ + Cl-

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17
Q

Homolytic bond fission

A

Covalent bond breaks, 2 electrons move into different atoms

E.g. Cl2–> 2Cl radicals

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18
Q

Hydrocarbons definition

A

Compound of only hydrogens and carbons

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19
Q

Bonds in alkanes

A

Strong
Non polar
Little polarisation (C and H similar electronegativities)
Tetrahedral arrangement negates any dipoles present
Weak van der waals

20
Q

Alkanes are…

A

Unaffected by ions/polar molecules
Low melting and boiling points (weak Van der Waals)
Insoluble in water

21
Q

Liquid alkanes are…

A

Good solvents for non polar molecules however don’t dissolve ionic or polar compounds

22
Q

Combustion of alkanes

A

Good fuels- burn exothermically on presence of oxygen to produce CO2 and water vapour

23
Q

Benefits to burning fossil fuels

A

Needed for transport, electricity generation, cooking, heating

24
Q

Disadvantage of burning fossil fuels

A
CO2 (greenhouse gas) leads to global warming
Can for SO2 which contributes to acid rain
Limited supply of oxygen when burning = incomplete combustion forming CO (toxic gas)
Not sustainable (crude oil non-renewable)
25
Q

Halogenoalkanes formula

A

Alkanes + halogens –(UV light)–> halogenoalkanes

26
Q

Halogenoalkanes is what type of reaction?

A

Substitution reaction (1 or more H atoms replaced with halogen)

27
Q

Halogenoalkanes used as..

A

Dry cleaning solvents and refrigerants

No longer used as aerosol propellants as they damage ozone layer

28
Q

Halogenoalkanes require UV light to make so is a …

A

Photochemical reaction

29
Q

Photochlorination of methane equation

A

CH4(g) + Cl2(g) –(UV light)–> CH3Cl(g) + HCl(g)

30
Q

Mechanism of Photochlorination of methane

A
Step 1- initiation
UV light breaks Cl2 bond (Homolytic fission)
Cl2--(UV light)--> 2Cl•
Step 2- propagation
CH4 + Cl•--> •CH3 +HCl
Methyl radical reacts with Cl2
•CH3 + Cl2--> CH3Cl + Cl•
Further substitution (2 further propagation steps)
CH3Cl + Cl•--> •CH2Cl + HCl
•CH2Cl + Cl2--> CH2Cl2 + •Cl
Step 3- Termination
2Cl•--> Cl2
Cl• + •CH3--> CH3Cl
2•CH3--> CH3CH3
31
Q

Hexane can be a product of Photochlorination of methane

A

2•C3H7–> C6H14

Formed from 2 radicals

32
Q

Mechanism of reaction of halogens + alkanes in UV light

A

Radical substitution

33
Q

C-H and C-C form

A

Sigma bonds

34
Q

C=C bonds form

A

Pi bonds

35
Q

E-Z isomerism

A
E = opposite
Z = same
36
Q

Which is E and Z isomers?

A

Look at 2 groups at one end of double bond in terms of atomic numbers, highest atomic number=highest priority
Repeat for other 2 groups
Z if high priority groups on same side
E is high priority groups on opposite sides

37
Q

Ethene + Bromine

A

Step 1- electrophyllic attack on double bond
Induced dipole in Br2, d+Br joins to one C, other C becomes a carbocation, negative Br ion (heterolytic fission), Br ion bonds to cation using lone pair

38
Q

Mechanism of Ethene + Bromine reaction

A

Electrophyllic reaction

39
Q

Bromine water

A

Orange/brown decolourises in presence of alkene

40
Q

Catalytic hydrogenation

A

H molecules + unsaturated alkenes–> alkane
Electrophyllic addition
Nickel/Platinum/Palladium catalyst
High temp, high pressure

41
Q

Electrophyllic addition of hydrogen to ethene

A

d+H joins to a C, other C a carbocation, H- ion left, H- joins to carbocation

42
Q

Electrophyllic addition of hydrogen bromide to ethene

A

d+H joins to C, carbocation, Br- ion joins to carbocation

43
Q

Electrophyllic addition of HBr to propene

A

d+H joins to a C, carbocation, Br- joins to primary/secondary carbocation

44
Q

Which carbocation is Br likely to join to?

HBr to propene reaction

A

Secondary carbocation is most stable, has 2 electron releasing groups either side

45
Q

Secondary carbocation of HBr propene reaction forms

A

2-bromopropane

46
Q

Alkenes + substituted alkenes

A

Addition polymerisation

Form polymers