Organic Chem Flashcards

1
Q

Explain why the sulfur compounds formed in crude oil should be removed from the fractions before they are used for central heating fuel

A

Bc so2 can be produced which can cause acid rain

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2
Q

How are oxides of nitrogen formed

A

Nitrogen and oxygen from the air react at high temps

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3
Q

Suggest why the branched chain isomer shown has a lower boiling point than octane

A

As it is a MOLECULE so stronger vdw forces more energy needed to break

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4
Q

State a physical property of alkenes that allows them to be seperated from a mixture by fractional distillation

A

Boiling points

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5
Q

General formula of cyclo alkanes

A

Cnh2n bc 2 less hydrogens

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6
Q

General formula of cyclic alkenes

A

Cnh2n-2

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7
Q

Suggest how a partial blockage in the helicopter engine may affect the performance of it

A

Less energy given out by the fuel so less powerful. More fuel needs to be burnt for the same energy so increased costs

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8
Q

Give the name of the substance from which paraffin is obtained and state the name of this process

A

Crude oil and fractional distillation

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9
Q

How can we convert an alkene to an alkane by using a reagent. Give its formula

A

H2. Just add a h2

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10
Q

Why is thermal cracking used in industry

A

To produce products that are in greater demand or higher value so more profitable

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11
Q

Why are high temps needed for this

A

To break the c-c bonds or the c-h bonds

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12
Q

Use of alkenes

A

Fuel or like can be used to make plastics

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13
Q

When a sample of y is burnt in air a toxic gas is formed, what is this gas and what could we use to remove it and what is this called

A

Sulfur dioxide, extracted by calcium oxide. Flue gas desulfarisation or neutralisation

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14
Q

Why would x and y have similar boiling points?

A

AS they are similar sized molecules and so have have similar vdw forces BETWEEN MOLECULES.

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15
Q

What can carbon cause

A

Global dimming or exacerbates asthma problems respiratory

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16
Q

Why is NO toxic

A

Forms NO2 which can also form HNO3 asthma acid rain etc

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17
Q

Formula for removal of nitrogen oxide in a engine catalytic thing

A

2no+2co—-.>N2+2CO2

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18
Q

Two reasons why fractions collect at different levels in the fractionating columns

A

Different boiling points or larger or heavier fractions

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19
Q

Why doesn’t n and o combine in the air

A

As they don’t usually react but they react in engines due to high combustion temperatures which produces sufficient energy to break the n—-triple bond n bond

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20
Q

Equations for catalytic convertors of no and o2

A

2NO+O2–>2NO2

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21
Q

The equation for hno3 made

A

4NO2+O2+2H20—-> 4HNO3

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22
Q

Suggest one reason why the combustion was incomplete

A

As there is not enough oxygen available for complete combustion

23
Q

Why is platinum or just catalysts used in converters 2 reasons

A

Efficiency/cost and provides a bigger surface area or increased reaction rate

24
Q

What is the reason that calcium oxide is used for fsd

A

It neutralizes the gas

25
If you have to give a functional group isomer for a alkene what is the only one you can give
A cyclo alkane
26
State two features of a hydroxide ion that causes it to act as a nucleophile
It has a lone pair of electrons and a neg charge
27
Water molecules can act as nucleophiles in a similar reaction. How do they compare with that of....
They are poorer nucleeophiles as they are neutral not negatively charged
28
What extra step has to occur in the reaction of a neutral nucleophile such as water compared with the reaction of a negatively charged ion eg hydroxide ion
A proton (h+)ion has to be lost to (0)justnotes ensure it is neg
29
Define sterioisomers
Compound with the same structural formula but the atoms and groups attached have different spatial arrangements
30
What is meant by addition
Reaction where 2 molecules react forming one
31
Why is bromine- a non polar molecule able to react with propene
As it has a c=c electron dense area which induces a dipole in br2
32
One hazard associated with the solid product c....
Corrosive
33
Common use of a c15h smth
Lubricant fuel oil or smth
34
Main economic reason why alkanes are cracked
Alkanes are cracked to produce substances that are in high demand
35
Why are the boiling points of x and y similar
As they have similar vdws.
36
Explain how the cahn ingold prelog priority rules can be used to deduce the full iupac name of this compound
Consider the groups attached to the right hand carbon of the c=c bond. Consider the atomic number and what takes priority. Same for the left side. Then determine whether their on the same side or the opposite side to determine whether the isomer is a e or a z. And the rest of the iupac name is....
37
Explain why the melting point of a longer alkane is higher than a shorter one
Longer carbon chain more electrons stronger vdw forces between molecules
38
When a sample of y contaminated with ch3sh is burned completely in air a toxic gas is formed. Identify it and name a compound that could be used to remove it
Sulfur dioxide and calcium oxide
39
How can isooctane be seperated from octane
Fractional distillation- isoocatne has a lower bp so would boil first and condensed and collected
40
Explain why determining the precise relative molecular mass of propanal and prop-2-en-ol by mass spec could not be used to distinguish between these 2 compounds
As they have the same molecular fomrula so the same mr
41
Give one reason why bonds in molecules such as co2 and 111 trifluoromethame absorb infrared radiation
As bonds vibrate or as bonds are polar
42
Show apparatus for refluxing
Condensor flask
43
Why do anti bumping granules prevent bumping
As they form smaller bubbles preventing larger bubbles to be formed
44
Explain why the halogenoaklane is attacked by the nucleophile in this reaction
Bromine is more electroneg than c C is electron def Lone pair on nucleophile donated to electron deficcient c
45
conditions and reagents for elimination and nucleophillic
ethanolic koh or naoh (proton acceptor) nucleophillic- naoh or koh aqueous acts as an electron pair donor
46
explain how infrared spec can be used to determine a molecule`
shows a peak in the range of... reference the fingerprint region to identify an alcohol and it matches with database spectra
47
how can we seperate isooctane from octane
fractional dist, one with lower bp boils first and then isooctane condenses and can be collected
48
would you expect to find a plascticiser in the pvc used to insulate electrical cables and why
C yes bc pvc needs to be bendy
49
explain why branched alkanes have less boiling point than straight chained alkanes
stronger van der waals as the nonane molecules packs closer together
50
explain why compound d with a c and a br reacts more quickly than a with a c and a cl
bc the c-br bond is weaker than c-cl, you have to refer to the bonds not about the size or electroneg or whatever
51
State one way that the infrared spectrum of Isomer 3 is different from the infrared spectrum of Isomer 4.
different fingerprint regions
52
define the term fraction
a group of hydrocarbons with similr bps
53
Carbon dioxide is formed when petrol is burned. Carbon dioxide acts as a greenhouse gas when it absorbs infrared radiation.Give a reason why carbon dioxide absorbs infrared radiation.
as c=o bonds vibrate at the same frequency as infrared radiatiom