Organic Chemistry - Alkanes, Alkenes, Crude Oil and Alcohols

?
  • Created by: Supernova
  • Created on: 14-06-20 08:06
Organic Chemistry
Study of compounds containing carbon and hydrogen
1 of 67
Hydrocarbons
Hydrocarbons are compounds that contain the elements carbon and hydrogen only
2 of 67
Molecular formula
Molecular formula of a compound gives the number of atoms of each element present in one molecule of the substance
3 of 67
Empirical formula
Empirical formula is the simplest whole number ratio of atoms of each element in the compound
4 of 67
Structural formula
Structural formula shows how atoms are joined up in the molecule
5 of 67
Displayed formula
Displayed formula shows all the atoms separately and all the bonds between them
6 of 67
Saturated hydrocarbon
Saturated hydrocarbon is a hydrocarbon containing only single bonds
7 of 67
Unsaturated hydrocarbon
Unsaturated hydrocarbon is a hydrocarbon containing at least one carbon-carbon double bond
8 of 67
Homologous series
A group of organic compounds that contain the same general formula and same functional group. Each members differ from the next member by a CH2 unit.
9 of 67
Features of the homologous series
They have the: Same general formula, Similar chemical properties due to the same functional group, Differ from the next CH2 unit and has a gradual increase in physical properties such as solubility, melting and boiling point
10 of 67
Isomers of Alkanes
Isomers are compounds with the same molecular formula but different displayed / structural formula
11 of 67
Alkanes
Saturated hydrocarbons with only single carbon bonds
12 of 67
General formula/Equation of Alkanes
CnH2n+2
13 of 67
First 10 Alkanes
1.Methane 2.Ethane 3.Propane 4.Butane 5.Pentane 6.Hexane 7.Heptane 8.Octane 9.Nonane 10.Decane
14 of 67
Methane
Molecular formula - CH4 Structural formula - CH4
15 of 67
Ethane
Molecular formula - C2H6 Structural formula - CH3CH3
16 of 67
Propane
Molecular formula - C3H8 Structural formula - CH3CH2CH3
17 of 67
Butane
Molecular formula - C4H10
18 of 67
Pentane
Molecular formula - C5H12
19 of 67
Isomers of C4H10
Butane and 2-methyl-propane
20 of 67
Isomers of C5H12
Pentane, 2-methyl butane and 2,2-dimethyl propane
21 of 67
Physical properties of Alkanes
They are colourless gases up to 4 carbon atoms or liquids from 5 carbon atoms to 10. They are insoluble in water, but soluble in organic solvents such as propane
22 of 67
Chemical properties/reactions of Alkanes
Combustion, Incomplete combustion and Substitution reaction
23 of 67
Complete combustion of Alkanes
Alkanes undergo complete combustion when they react with excess oxygen to produce CO2 and H2O. This reaction produces heat energy, so used as fuels.
24 of 67
Incomplete combustion of Alkanes
Alkanes undergo incomplete combustion when they react with limited supply of oxygen. The products are carbon (soot), carbon monoxide and water. The flame is smoky and less heat is given out.
25 of 67
Substitution of Alkanes
Alkanes undergo substitution reaction when they react with halogens such as chlorine (Cl2) or bromine (Br2). The condition for this reaction is UV light
26 of 67
Alkenes
Alkenes are unsaturated hydrocarbons with Carbon-Carbon double bonds (C=C)
27 of 67
general formula of alkenes
CnH2n
28 of 67
Isomers of Alkenes
Compounds that have the same molecular formula but different displayed formulae
29 of 67
Alkenes with up to four carbon atoms in molecule
ethene, propene and butene
30 of 67
ethene
Molecular formula - C2H4 Structural formula - CH2=CH2
31 of 67
propene
Molecular formula - C3H6 Structural formula - CH2=CHCH3
32 of 67
butene
(but-1-ene isomer) Molecular formula - C4H8 Structural formula - CH2=CH2CH3 (but-2-ene isomer) Molecular formula - C4H8 Structural formula - CH3CH = CHCH3
33 of 67
What are the Isomers of C4H8
but-1-ene, but-2-ene and 2-methyl-propane
34 of 67
What are the isomers of C5H12
Pentane, 2-methyl butane and 2,2-dimethyl propane
35 of 67
Chemical reactions of Alkenes
Complete combustion, Incomplete combustion and Addition reaction
36 of 67
Complete combustion of Alkenes
Alkenes undergo complete combustion when they react with excess oxygen
37 of 67
Incomplete combustion of Alkenes
Alkenes undergo incomplete combustion when they react with limited supply of oxygen
38 of 67
Addition reaction
Addition reaction occurs when two reactants react each other to form one product
39 of 67
Use of Bromine Water to distinguish between Alkane and Alkene
Bromine water is an orange solution of bromine. When bromine water is shaken with an Alkane, it will remain as an orange solution as alkanes do not have double carbon bonds (C=C). But when bromine water is shaken with an alkene, the alkene will decol
40 of 67
Crude oil
A mixture of hydrocarbons. Thick, sticky, black liquid that is found under porous rock (under the ground and under the sea).
41 of 67
Viscosity of crude oil
Viscosity refers to the ease of flow of a liquid. High viscosity liquids are thick and flow less easily. If the number of carbon increases, the attraction between the hydrocarbon molecules also increases which results the liquid become more viscous
42 of 67
Colour of crude oil
As carbon chain length increases colour of liquid gets darker as it gets thicker and more viscous.
43 of 67
melting/boiling point of crude oil
As the molecules get larger, the intermolecular attraction becomes greater. So more heat is needed to separate the molecules. With increasing molecular size there is an increase in boiling point.
44 of 67
Volatility of crude oil
Volatility means the tendency for a substance to vaporise. With the increasing molecular size, the hydrocarbon liquids become less volatile. As the attraction between the molecules increases with the increasing molecular size.
45 of 67
Flammability of crude oil
As molecules get larger, Flammability decreases
46 of 67
Cracking
Cracking is the breaking down of long chain alkanes in to more useful short-chained alkanes and alkenes. This is referred as catalytic cracking.
47 of 67
Conditions for cracking
Catalyst of Aluminium oxide (Al2O3) and temperature of 600-700°c
48 of 67
Why cracking is necessary
the amount of shorter chain hydrocarbons produced is far less than needed (e.g. gasoline fraction) and there is a higher demand for shorter chain hydrocarbons. This is why cracking is necessary to increase the supply of shorter chain hydrocarbons.
49 of 67
Long-chain hydrocarbons
large number of hydrocarbon molecules. More viscous and less flammable so less useful.
50 of 67
Short-chain hydrocarbons:
small numbers of hydrocarbon molecules.
51 of 67
Alcohol
Family of organic (carbon-based) compounds that all contain the -OH group that is responsible for their chemical properties and reactions.
52 of 67
Functional group of Alcohols
The functional group in the alcohols is the hydroxyl group (-OH).
53 of 67
General formula of alcohols
CnH2n + 1OH
54 of 67
Methanol
Molecular formula - CH3OH Structural formula - CH3OH
55 of 67
Ethanol
Molecular formula - Ć2H5OH Structural formula - CH3CH2OH
56 of 67
Complete combustion of ethanol
Ethanol + Oxygen → Carbon dioxide + water / C2H5OH(g) + 3O2(g) → 2CO2 (g) + 3H2O(l)
57 of 67
Fermentation
Fermentation is a conversion of sugars into ethanol, under anaerobic conditions (limited air), brought about by microorganism yeast
58 of 67
Equation for fermentation of glucose by anaerobic respiration
Glucose → Ethanol + Carbon Dioxide / C6H12O6(aq) → 2C2H5OH(aq) + 2CO2(g)
59 of 67
Conditions required for fermentation
yeast (contains zymase enzyme-catalyst), solution of sugar (glucose), temp of 30-35°c and anaerobic conditions
60 of 67
Reacting ethene with steam (hydration
A mixture of ethene and steam is passed over a hot catalyst of phosphoric acid at a temperature of 300°c and 60-70 atmospheres of pressure and is then condensed into a liquid for use
61 of 67
Equation for the reaction between ethene and steam
Ethene + Water → Ethanol / C2H4(g) + H2O(g) → C2H5OH(g)
62 of 67
Conditions required for direct hydration of Ethene
catalyst - phosphoric acts, temperature - 300°c, pressure - 60 atm
63 of 67
Advantages of Fermentation
uses renewable resources (sugar cane) and mild conditions are needed so its cheaper
64 of 67
Disadvantages of Fermentation
slow and ethanol produced is not pure
65 of 67
Advantages of hydration of ethene
Faster process and produces purer ethanol
66 of 67
Disadvantages of hydration of ethene
uses non-renewable resources (crude oil) and extreme conditions are needed (high temperature and high pressure) so its expensive
67 of 67

Other cards in this set

Card 2

Front

Hydrocarbons

Back

Hydrocarbons are compounds that contain the elements carbon and hydrogen only

Card 3

Front

Molecular formula

Back

Preview of the front of card 3

Card 4

Front

Empirical formula

Back

Preview of the front of card 4

Card 5

Front

Structural formula

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all Organic Chemistry resources »