Brainscape's Knowledge GenomeTM

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


See full index

Chemistry (personal) > Topic 6 > Flashcards

Topic 6 Flashcards

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

Test for a C=C

A

Bromine water decolourises (electrophillic addition)

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

Structural isomers

A

Compounds with the same molecular formula, but different structural formulae (chain, position, functional group isomerism)

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

Stereoisomers

A

Compounds with the same molecular and structural formulae, but a different spatial arrangement of atoms (geometric and optical isomerism)

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

Process of fractional distillation

A

Crude oil heated and enters distillation column as a vapour.
Column is hotter at the bottom and cooler at the top.
The vapour cools as it rises through a series of bubble caps.
Different fractions condense at different heights in the column depending on their boiling temperature.
The liquid of each fraction is piped away (gas leaves at top).

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

Fractional distillation fractions

A 
Refinery gas
Petrol
Naptha
Kerosene
Diesel oil
Lubricating oil
Fuel oil
Bitumen
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Cracking

A

Use of heat/catalysts to break down long chain hydrocarbons into shorter chain alkanes, alkenes and hydrogen.

Increases supply of shorter fractions (economically important)
Increases branching in chains
Alkenes are an important feedstock for chemicals

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

Reforming

A

Process that converts straight hydrocarbon chains into branched and cyclic hydrocarbons, by heating with a catalyst (eg. platinum).
More efficient combustion
Smoother burning, less knocking
Pre-ignition less likely

Isomerisation: straight to branched
Another type: straight to cyclic alkane to arene

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

Pollutants

A

Carbon monoxide
Lead
Sulfur dioxide
Oxides of nitrogen

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

Sigma bonds

A

Covalent bonds formed when electron orbitals overlap end on (axially)

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

Pi bonds

A

Covalent bonds formed when electron orbitals overlap side on

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

Free radical

A

A chemical species with an unpaired electron

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

Homolytic fission

A

A bond breaks to form two free radicals

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

Heterolytic fission

A

A bond breaks to form two oppositely charged ions

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

Electrophile

A

A chemical species which is attracted to an area of high electron density and accepts a pair of electrons to form a covalent bond.

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

Nucleophile

A

A chemical species which is attracted to an area of (partial) positive charge and donates a pair of electrons to form a covalent bond.

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

Free radical substitution

A

Alkane + halogen

Initiation: Molecule -> 2 free radicals
Propagation Molecule + free radical -> molecule + free radical
(note free radical changes each step and homolytic fission)
Termination: Free radical + free radical
Ends because a stable species is formed

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

Electrophillic addition

A

Alkene + halogen

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

Thermal stability of carbocations

A

Stability increases as the number of alkyl groups on the positively charged carbon atom increases (primary, secondary, tertiary).

Alkyl groups contain a greater electron density that H atoms, so they are electron releasing and electrons from the alkyl group are attracted towards the positively charged carbon atom. This reduces its positive charge and has a stabilising effect.

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

Alkene + hydrogen

A

Name: Hydrogenation
Product: Alkane
Conditions: heat, nickel catalyst

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

Alkene + halogen

A

Name: Halogenation
Product: dihalogenoalkanes

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

Alkene + water

A

Name: Hydration
Product: Alcohol
Conditions: heat, phosphoric acid catalyst

22
Q

Alkene + hydrogen halide

A

Product: Halogenoalkane

23
Q

Oxidation of alkenes

A

Product: Doil
Conditions: Potassium manganate (VII) (oxidising agent), water
Colour change from purple to colourless

24
Q

Primary halogenoalkane

A

1 R group attached to the R carbon atom bonded to the halogen

25
Q

Testing for reactivity of halogenoalkanes

A

Ethanol used as solvent
Add silver nitrate solution
Use water bath (50 degrees) to control temp
Time how long precipitate takes to form

26
Q

Trend in reactivity of halogenoalkanes

A 
Slowest
Chloro-  primary
Bromo-  secondary
Iodo-      tertiary
Fastest

Alkyl groups are electron releasing
C-X bond weakest in tertiary compounds
Weaker the bond, faster the hydrolysis

27
Q

Nucleophillic substitution reactions

A

Halogenoalkanes + nucleophile

28
Q

Primary alcohol

A

There is 1 alkyl group attached to the carbon atom which carries the OH group.

29
Q

Chlorination of primary and secondary alcohols

A

Reagent: Phosphorus (V) chloride (PCl5)
Conditions: Room temp
Extra products: Phosphorus chloride (POCl3) and HCl

30
Q

Chlorination of tertiary alcohols

A

Reagent: Conc. HCl
Conditions: Shake at room temp
Extra products: Water

31
Q

Bromination of alcohols

A

Reagent: Hydrobromic acid
-made from KBr and 50% conc. H2SO4
Extra products: Water

32
Q

Iodination of alcohols

A

Reagent: phosphorus (III) iodide- PI3
-made from red phosphorus and iodine
Conditions: Heat under reflux
Extra products: H3PO3

33
Q

Elimination/dehydration of alcohols

A

Reagent: Phosphoric (V) acid- catalyst
Products: Alkene and water

34
Q

Oxidation of primary alcohols

A

Oxidising agent: Acidified potassium dichromate (VI) solution
Distill with excess alcohol- aldehyde and water
Heat under reflux with excess oxidising agent- carboxylic acid and water

35
Q

Oxidation of secondary alcohols

A

Oxidising agent: Acidified potassium dichromate (VI) solution
Heat under reflux
Produces ketone and water

36
Q

Test for oxidation

A 
Potassium dichromate (VI) solution (reduced)
Orange -> green
37
Q

Test for aldehyde

A

Fehling’s solution or Benedict’s solution (reduced)
Warm
Blue -> red-brown

38
Q

Test for carboxylic acid

A

Add magnesium or calcium carbonate

Effervescence

39
Q

Why does incomplete combustion occur?

A

There is a lack of oxygen.

40
Q

What happens to the products of free radical substitution when there is excess halogen?

A

Further substitution reactions

41
Q

Halogenoalkane and potassium hydroxide

A

Conditions: heat under reflux
Products: alcohol, potassium halide
Reaction: nucleophilic substitution

42
Q

Halogenoalkane and potassium cyanide

A

Conditions: heat under reflux
Products: nitrile, potassium halide
Reaction: nucleophilic substitution

43
Q

Halogenoalkane and ammonia

A

Conditions: heat in a sealed tube at high pressure
Products: primary amine, hydrogen halide
Reaction: nucleophilic substitution

44
Q

Halogenoalkane and water

A

Conditions: warm
Products: alcohol, hydrogen halide
Reaction: nucleophilic substitution

45
Q

Halogenoalkane and ethanolic potassium hydroxide

A

Conditions: heat, ethanol used as a solvent
Products: alkene, water, potassium halide
Reaction: elimination (OH- acts as a base, not nucleophile)
Note: reacts with H atom on the C atom next to the C atom bonded to the halogen!

46
Q

Practical notes for chlorination of a tertiary alcohol

A

Unwanted substances in products: alcohol, HCl, water
Two layers- upper organic layer wanted
Ensure alcohol in lower layer- anhydrous calcium chloride
Remove lower layer- separating funnel
Remove HCl- sodium hydrogen carbonate, remove lower layer
Remove water- anhydrous sodium/magnesium sulphate
Distil and collect 50-52 degrees fraction
Test product: ethanol, NaOH, warm, nitric acid and silver nitrate = white ppt

47
Q

How does burning fuels lead to the corrosion of buildings?

A

SO2 and NO2 form when fossil fuels are burned
React with water forming sulfuric acid and nitric acid
Acid rain
Reacts with limestone forming soluble compounds

48
Q

Which type of covalent bond is stronger?

A

Sigma bonds are stronger than pi bonds
Good overlap of S orbitals in sigma bonds
Poor overlap of P orbitals in pi bonds
Because P orbitals are parallel

49
Q

What happens to pi and sigma bonds in addition reactions?

A

Sigma bonds remain
Pi bonds break because they are weaker
Because orbital overlap is lateral, so overlap is poor
Carbocation intermediate forms

50
Q

Why does the initiation step for free radical substitution involve breaking Cl-Cl bond rather than C-H bond?

A

The Cl-Cl bond is weaker than a C-H bond

51
Q

Why do halogenoalkanes react with NaOH faster than with water?

A

OH- is a stronger nucleophile than water

Higher concentration of OH- ions in NaOH than water

Chemistry (personal) (15 decks)

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