Brainscape's Knowledge GenomeTM

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


See full index

Chemistry > Topic 6B - Alkanes > Flashcards

Topic 6B - Alkanes Flashcards

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

6B.8

What is the general formula for alkanes?

A

C(n)H(2n+2)

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

6B.9

What are the saturated hydrocarbons?

A

Alkanes and cycloalkanes.

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

6B.10

What is reforming?

A

The processing of straight-chain hydrocarbons into branched-chain alkanes and cyclic hydrocarbons for efficient combustion.

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

6B.10

How are alkane fuels obtained?

A

From the fractional distillation, cracking and reforming of crude oil.

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

6B.10

At what temperature does crude oil enter the fractional distillation tower?

A

400 degrees centigrade.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

6B.10

What conditions are used for reforming?

A

High pressure, 500 degrees centigrade with a platinum catalyst.

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

6B.10

What is a valuable by-product of reforming?

A

Hydrogen.

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

6B.10

When a component of crude oil has a boiling temperature that is too high what happens to it?

A

It undergoes vacuum distillation.

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

6B.11

Which pollutants are formed during the combustion of alkane fuels?

A

Carbon monoxide, nitrous oxides, sulfur oxides, carbon particulates and unburned hydrocarbons.

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

6B.11

What is always a product of combustion even if it is incomplete?

A

Water is always a product.

[This is because oxygen always combines with hydrogen in preference to carbon].

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

6B.12

What are the dangers of carbon monoxide being produced during the combustion of alkane fuels?

A

Carbon monoxide is a toxic gas that combines strongly with haemoglobin so blood can carry less oxygen.

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

6B.12

What are the dangers of nitrous oxides being produced during the combustion of alkane fuels?

A

Nitrous oxides can react with water and more oxygen to form nitric acid. This then goes on to form acid rain.
[In bright sunshine, nitrogen dioxide molecules break down into nitrogen monoxide and oxygen free radicals. The oxygen free radicals can react with oxygen to produce ozone, a serious pollutant. But this ozone can react with unburned hydrocarbons to produce irritant chemicals that can build up into photochemical smog in the absence of wind.]

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

6B.13

How do catalytic converters improve air quality?

A

By removing the pollutants that would otherwise be released from car exhausts.

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

6B.13
In a catalytic converter, carbon monoxide and nitrogen monoxide react in a redox reaction to produce what safer products?

A

Carbon dioxide and nitrogen.

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

6B.13

Although catalytic converters remove harmful pollutants, suggest a reason for why they are not ideal.

A

Carbon dioxide is still produced and it is a greenhouse gas.

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

6B.14

What does the term carbon neutral mean?

A

When the carbon dioxide released is balanced by actions which remove an equivalent amount of carbon dioxide from the atmosphere.

17
Q

6B.14

Give an example of a source of biodiesel.

A

Soya beans (or maize)

18
Q

6B.14

In terms of biofuels, why are soya beans a better source than maize?

A

Energy is not needed for distillation in the production of the fuel.

19
Q

6B.14

How can ethanol be produced as a biofuel?

A

Fermentation of starch produces glucose that is further fermented to ethanol. In Brazil sugars from sugar cane are used in fermentation.

20
Q

6B.14

How is biodiesel produced?

A

By extracting and processing oils from crops such as rapeseed.

21
Q

6B.15

What is a radical?

A

A species with an unpaired electron. [Denoted by a single dot in equations.]

22
Q

6B.15

How is a radical formed?

A

In the homolytic fission of a covalent bond. [UV light is needed for halogens]

23
Q

6B.16

When alkanes react with oxygen during combustion what two products are formed?

A

Water and carbon dioxide.

24
Q

6B.16

What mechanism is used in the substitution of a hydrogen for a halogen in a compound?

A

Free radical substitution.

25
Q

6B.16

What is the initiation step of free radical substitution?

A

Cl2 –> 2Cl(fr)

where (fr) is a free radical.

26
Q

6B.16

What are the two propagation steps in free radical substitution?

A

CH3CH3 + Cl(fr) –> CH3CH2(fr) + HCl
CH3CH2(fr) + Cl2 –> CH3CH2Cl + Cl(fr)
where (fr) is a free radical.

27
Q

6B.16

Give an example of a termination step in free radical substitution?

A

2CH3CH2(fr) –> CH3CH2CH2CH3
or
2Cl(fr) –> Cl2
where (fr) is a free radical.

28
Q

6B.17

Suggest a limitation of free radical substitution.

A

A mixture of products is formed due to further substitution of products.

Chemistry (5 decks)

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