Brainscape's Knowledge GenomeTM

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


See full index

Chemistry Mocks > C6.2 > Flashcards

C6.2 Flashcards

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

What are hydrocarbons?

A

Compounds that only contain hydrogen and carbon

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

Why do alkanes form a homologous series?

A

The same general formula and they are all saturated :

Cn H2n+2

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

List some alkanes

A

Methane - 1
Ethane - 2
Propane - 3
Butane - 4

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

Displayed formulae of alkanes

A

Carbon atoms form 4 covalent bonds and hydrogen atoms form one covalent bond

Butane : H - C - C - C - C -H (and the upper bit too)
| | | |
H H H H

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

Complete combustion of alkanes

A

Carbon atoms oxidised to form CO2

Hydrogen atoms oxidised to form water

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

Incomplete combustion of alkanes

A

Water is still formed BUT carbon is oxidised to carbon monoxide and this is a problem because CO is toxic (some carbon atoms may not be oxidised at all and release carbon atoms - soot)

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

Alkenes homologous series

A

Have a carbon=carbon double bond making them UNSATURATED

CnH2n

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

How to model alkenes?

A

On the far right have the double bond and above the carbon atom that starts the double bond (there is no hydrogen atom)

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

How do alkenes react?

A

Just like alkane combustion
BUT they have a functional group (an atom or a group of atom that allows them to take part in some reactions and in this case it is a carbon-carbon double bond) -> allows them to undergo addition reactions

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

Addition reaction

A

Alkenes react with other molecules to form a larger product
Test for in saturation :
Alkene + bromine -> dibromoalkene
CARBON CARBON DOUBLE BOND BREAKS
Bromine only reacts with alkenes because they are unsaturated (decolorises the bromine water)
Also undergo addition reaction with hydrogen : forms alkanes (presence of nickel catalyst)
Ethene + hydrogen -> ethane

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

What is crude oil?

A

Crude oil is a fossil fuel and it was formed from the remains of marine organisms that lived millions of years ago - buried deep in the sea bed. It is a finite resource and that is why it is non - renewable (being used up at a faster rate than it is being formed) - only replenished on a time scale of a million years

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

How to make crude oil useful?

A

Crude oil is a mixture of alkanes that are separate from each other because they have different boiling points - larger hydrocarbons = stronger intermolecular forces = higher boiling point

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

How does fractionating distillation work?

A

Crude oil is heated and vapours are piled in the bottom of a fractionating column (temperature gradient) = hot at bottom and cold at the top, cools as it rises through the column and they condense into the liquid state if they reach a part that is cool enough.

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

Parts of crude oil (fractions)

A

LPG - refinery gases (lowest boiling point - dont condense, just leaves as gases)
Petrol - liquid
Paraffin - liquid
Diesel - liquid
Heating oil - liquid
Fuel oil - liquid
Bitumen - highest boiling point (solid at room temperature)

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

What is cracking?

A

Cracking is a chemical reaction that converted large alkane molecules into smaller alkane molecules and alkenes
Octane -> hexane + ethene

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

How is it done in oil refineries?

A

Heating oil fractions to a high temperature and passing them over a hot catalyst of alumina or silica - covalent bonds between atoms in large alkane molecules BREAK - can be done in classroom with a broken pot as catalyst

17
Q

Why is cracking carried out?

A

Large alkane molecules do not flow easily and are difficult to ignite - not useful as fuels (on the other hand, fractions;with smaller alkane molecules have lower boiling points and can flow easier + easier to ignite => useful as fuels)

18
Q

Why do oil refineries carry out cracking?

A

Help oil refineries match its supply of useful products with its customers’ demand for them - also produces alkenes which are useful for making polymers

19
Q

Why is crude oil important?

A

Vital in our lives + main source of fuel and feedstock for chemical industry

Chemistry Mocks (10 decks)

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