Brainscape's Knowledge GenomeTM

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


See full index

Chemistry gcse > Organic Chemistry > Flashcards

Organic Chemistry Flashcards

1
Q

What is a hydrocarbon?

A

Any compound that is formed from carbon and hydrogen atoms only

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

Alkanes

A

The simplest type of hydrocarbon
CnH2n+2
Each carbon atom forms four single covalent bonds
First four alkanes are methane, ethane, propane and butane

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

Methane formula

A 
CH4
     H
      |
H-C-H
      |
     H
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Ethane formula

A 
C2H6     
     H   H
      |    |
H-C-C-H
      |    |
     H   H
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Propane formula

A

C3H8

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

Butane formula

A

C4H10

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

What gives hydrocarbon molecules varying properties?

A

They vary in size

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

What happens to the properties of hydrocarbons as the molecules get larger?

A

It gets more viscous, its boiling point gets higher, the less volatile it is, the less easily it ignites

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

Complete combustion of hydrocarbons equation

A

Hydrocarbon + oxygen —> carbon dioxide + water (+energy)

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

Why are hydrocarbons used as fuels?

A

They release a large amount of energy when they combust completely

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

Hydrocarbon combustion waste products

A

CO2 and H2O

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

How is crude oil formed?

A

Over millions of years from the fossilised remains of plankton

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

Where is crude oil found?

A

In the porous rocks in the Earth’s crust

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

What is crude oil made up from?

A

Hydrocarbons

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

How are the components of crude oil separated?

A

Fractional distillation

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

Why does fractional distillation work for hydrocarbons?

A

Different sized molecules of hydrocarbons have different boiling points

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

What piece of equipment does fractional distillation take place in?

A

Fractionating column

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

What are the stages of fractional distillation?

A

1) the crude oil is heated until it evaporates
2) the molecules move up the fractionating column which is hotter at the bottom
3) larger molecules condense at the hotter bottom of the column and are collected
4) the shorter molecules condense at the cooler top of the column and are collected

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

Cracking

A

Splitting up long chain hydrocarbons into shorter chain hydrocarbons

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

Which hydrocarbons are more useful: long chain or short chain?

A

Short chain as they are flammable so make good fuels.

Long ones for, thick gloopy liquids like tar which aren’t that useful

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

What is the process of catalytic cracking?

A

1) the hydrocarbons are heated until they vaporise
2) the vapour is passed over a hot catalyst
3) thermal decomposition then takes place

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the products of cracking?

A

Both alkanes and alkenes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Why are hydrocarbons split into smaller molecules?

A

There is a higher demand for short hydrocarbons as they easy to ignite and have low boiling points so are used in fuels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the main difference between alkenes and alkanes?

A

Alkenes have a double carbon bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What are hydrocarbons that have double bonds described as?
Unsaturated | Alkenes have 2 fewer hydrogens compared with alkanes containing the same number of carbon atoms
26
What is the general formula for an alkene?
CnH2n
27
Why are alkenes more reactive than alkanes?
Because of the C=C bond
28
Why do alkenes burn with a smokier flame than alkanes?
They go through incomplete combustion
29
What happens in incomplete combustion?
Carbon monoxide is produced which is poisonous. Soot is given off
30
What happens during the combustion of hydrocarbons?
Carbon and hydrogen are oxidised, energy is released, waste products are released into the atmosphere
31
What two types of cracking are there?
Catalytic cracking | Steam cracking
32
What is the method of steam cracking?
1) vaporise the hydrocarbons 2) mix them with steam 3) heat them to a very high temperature
33
Balanced chemical equations for cracking etc. | Decane
HHHHHHHHHH HHHHHHHH H H HCCCCCCCCCCH —> HCCCCCCCCH + C=C HHHHHHHHHH HHHHHHHH H H decane octane Ethene(alkene)
34
Cracking equation
Long chain hydrocarbon —> shorter alkane molecule + alkene
35
Ethene formula
C2H4 H H C=C H H
36
Propane formula
C3H6 H H H H-C-C=C H H
37
Butene formula
C4H8 H H H H H-C-C-C=C H H H
38
Pentene formula
C5H10 H H H H H H-C-C-C-C=C H H H H
39
Standard equation for incomplete combustion of alkenes
Alkene + oxygen —> carbon + carbon monoxide + carbon dioxide + water
40
What does incomplete combustion result in?
Smoky yellow flame and less energy being released compared to the complete combustion of the same compound
41
How do alkenes react?
Most of the time they react via addition reactions. The carbon – carbon double bond opens up to leave a single bond and the new atom is added to each carbon R H Y H C=C + X-Y —> R-C-C-H (R= carbon chain) H H H X
42
what is Hydrogenation?
Addition of hydrogen
43
Hydrogenation of alkenes
Hydrogen can react with the double bonded carbons to open up the double bond and form the equivalent, saturated, alkane. The alkene is reacted with hydrogen in the presence of a catalyst. R H H H C=C + H2 —> R-C-C-H H H H H
44
Halogens reacting with alkenes
Alkenes will also react in addition reactions with halogens such as bromine, chlorine and iodine. The molecules formed are saturated with the C=C carbons each becoming bonded to a halogen atom H H H Br C=C + Br2 —> H-C-C-H H H Br H
45
What test can be used to differentiate between alkanes and alkenes?
Shaken bromine water
46
What colour does an alkene go in the shaken bromine water test?
Colourless
47
What colour does an alkane go in the shaken bromine water test?
Stays Orange
48
Steam reacting with alkene it form alchohols
When alkenes react with steam, water is added across the double bond and an alcohol is formed E.g. ethanol can be made by mixing Ethene with steam and then passing it over a catalyst H H H H C=C + H2O —> H-C-C-O-H H H Br H
49
What are monomers?
Small molecules with a double bond that can join together to make polymers
50
What are plastics made up of?
Long chain molecules called polymers | Usually carbon based and their monomers are often alkenes
51
Polymerisation
When lots of small molecules called monomers join together | Usually needs high pressure and a catalyst
52
Addition polymerisation
Monomers that make up addition polymers have double covalent bonds Lots of unsaturated monomers (alkenes) can open up their double binds and join together to form polymer chains
53
Addition polymerisation reaction example
H H H H n( C=C ) —> -(-C-C-)- H H H H n Many single Ethenes —> poly(ethene)
54
Homologous series
A group of chemicals that react in a similar way because they have the same functional group E.g alcohols and alkanes
55
General formula of an alcohol
CnH2n+1OH
56
Methanol formula
CH3OH H H-C-O-H H
57
Ethanol formula
C2H5OH
58
Propanol formula
C3H7OH
59
Butanol formula
C4H9OH
60
What do all alcohols have?
An -OH functional group
61
Alcohol characteristics
Flammable Undergo complete combustion in air to produce CO2 and H2O Soluble in water React with sodium to produce hydrogen Can be oxidised to produce carboxylic acid
62
Carboxylic acid
``` Different alcohols form different carboxylic acids Methanol is oxidised to methanoic acid Ethanol to ethanoic acid All have -COOH homologous series of compounds ```
63
What are alcohols used as?
- Methanol and ethanol are used as solvents in industry as they can dissolve most things water can dissolve but they can also dissolve substances that wate can’t dissolve e.g. hydrocarbons, oils and fats - first 4 alcohols are used as fuels e.g. ethanol as a fuel in spirit burners
64
Fermentation
A way of making ethanol 1) fermentation uses an enzyme in yeast to convert sugars into ethanol. Carbon dioxide is also produced. The reaction occurs in solution so the ethanol produced is aqueous 2) Fermentation happens fastest at a temperature of around 37 °C, in a slightly acidic solution and under anaerobic conditions (no oxygen) 3) Under these conditions the enzyme in yeast works best to convert the sugar to alcohol. If the conditions were different, for example a lower pH/higher temperature or higher pH/ lower temperature, the enzyme could be denatured (destroyed) or could work at a much slower rate.
65
Methanoic acid formula
HCOOH ``` O || H-C | OH ```
66
Ethanoic acid formula
CH3COOH
67
Propanoic acid formula
C2H5COOH
68
Butanol acid formula
C3H7COOH
69
What is formed when a carboxylic acid reacts with a carbonate?
Carbon dioxide
70
What do carboxylic acids form when dissolved in water?
Acidic solutions
71
What is formed when carboxylic acids react with alcohols in the presence of an acid catalyst?
They form esters
72
How are esters formed?
When carboxylic acids and alcohols react
73
What is functional group found in esters?
-COO
74
How are esters named?
The prefix of the alcohol with -yl as a suffix and the prefix of the acid with-oate as the suffix. For example, ethanol and ethanoic acid would react to form ethyl ethanoate
75
What are properties of esters?
They are volatile and have distinctive smells
76
Formation of esters equation
Alcohol + carboxylic acid —> ester + water
77
What is a condensation polymerisation reaction?
Monomers join together to form large polymer molecules and lose small molecules such as water
78
What do amino acids form when they join by condensation polymerisation?
Polypeptides and water
79
What process do amino acids go through to form larger molecules?
Condensation polymerisation
80
What is dna?
Stores the genetic material of living organisms
81
What is dna made up of?
4 nitrogen bases, a phosphate and a sugar
82
What are the 4 nitrogen bases in dna?
G C A T
83
What is a nucleotide?
Half of one rung of DNA- A phospate, a sugar and a base
84
Polymers of sugar
Starch and cellulose
85
What organism makes starch and cellulose?
Plants
86
What type of molecules are starch, cellulose and sugars?
Carbohydrates
87
Sumo,e sugars can form polymers
Sugars are small molecules containing carbon, oxygen and hydrogen Sugars can react together through polymerisation reactions to form larger polymers

Chemistry gcse (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions