5.2.2
Cracking
Cracking
Cracking
Cracking is the process of converting alkanes into alkenes and shorter alkanes. We crack alkanes because the shorter chain alkanes are more valuable (they are used as fuel).
Thermal cracking
Thermal cracking
- Thermal cracking uses harsh conditions like high temperature and high pressure.
- It breaks the alkanes into a high percentage of alkenes and comparatively few alkanes.
- Thermal cracking is done at about 1,000oC and 70 atm pressure.
Catalytic cracking
Catalytic cracking
- Using a catalyst allows you to lower the temperatures and pressures needed for the reaction. This reduces costs and makes the reaction faster.
- Catalytic cracking is done at 450oC and only just above atmospheric pressure.
- The catalyst we use is called a zeolite. This is an ionic compound containing aluminium, silicon, and oxygen.
- You tend to get molecules containing benzene rings and short hydrocarbons.
1Physical Chemistry
1.1Atomic Structure
1.1.1Fundamental Particles
1.1.2Isotopes & Mass Number
1.1.3Mass Spectrometry
1.1.4Electron Shells, Sub-Shells & Orbitals
1.1.5Electron Configuration
1.1.6Ionisation Energy
1.1.7Factors Affecting Ionisation Energies
1.1.8Trends of Ionisation
1.1.9Specific Impacts on Ionisation Energies
1.1.10End of Topic Test - Atomic Structure
1.1.11A-A* (AO3/4) - Atomic Structure
1.2Amount of Substance
1.3Bonding
1.3.1Ionic Bonding
1.3.2Covalent & Dative Bonding
1.3.3Carbon Structures
1.3.4Metallic Bonding
1.3.5Physical Properties
1.3.6Shapes of Molecules
1.3.7Polarity
1.3.8Intermolecular Forces
1.3.9Intermolecular Forces 2
1.3.10End of Topic Test - Bonding
1.3.11Exam-Style Question - Shape of Molecules
1.3.12A-A* (AO3/4) - Bonding
1.4Energetics
1.5Kinetics
1.6Equilibria
2Physical Chemistry 2 (A2 Only)
2.1Thermodynamics (A2 Only)
2.2Rate Equations (A2 Only)
2.3The Equilibrium Constant Kp (A2 Only)
2.4Electrochemical Cells (A2 Only)
2.5Acids & Bases (A2 Only)
2.5.1Brønsted-Lowry Acids & Bases (A2 Only)
2.5.2pH (A2 Only)
2.5.3The Ionic Product of Water (A2 Only)
2.5.4Weak Acids & Bases (A2 Only)
2.5.5pH Curves & Titrations (A2 Only)
2.5.6pH Curves & Titrations 2 (A2 Only)
2.5.7Buffer Solutions (A2 Only)
2.5.8End of Topic Test - Acids & Bases
2.5.9Exam-Style Question - Weak Acids
2.5.10A-A* (AO3/4) - Acids & Bases
3Inorganic Chemistry
3.1Periodicity & Trends
4Inorganic Chemistry 2 (A2 Only)
4.1Period 3 (A2 Only)
4.2Transition Metals (A2 Only)
4.2.1General Properties (A2 Only)
4.2.2Substitution Reactions (A2 Only)
4.2.3Shapes of Complex Ions (A2 Only)
4.2.4Colours of Ions (A2 Only)
4.2.5Variable Oxidation States (A2 Only)
4.2.6Titrations (A2 Only)
4.2.7Homogeneous Catalysts (A2 Only)
4.2.8Heterogeneous Catalysts (A2 Only)
4.2.9End of Topic Test - Transition Metals
4.2.10A-A* (AO3/4) - Transition Metals
4.3Reactions of Ions in Aqueous Solutions (A2 Only)
5Organic Chemistry 1
5.1Introduction
5.2Alkanes
5.3Halogenoalkanes
5.4Alkenes
5.5Alcohols
5.6Organic Analysis
5.7A-A* (AO3/4) - Organic 1
6Organic Chemistry 2 (A2 Only)
6.1Optical Isomerism (A2 Only)
6.2Aldehydes & Ketones (A2 Only)
6.3Carboxylic Acids & Esters (A2 Only)
6.4Aromatic Chemistry (A2 Only)
6.5Amines (A2 Only)
6.6Polymers (A2 Only)
6.7Biological Organic (A2 Only)
6.8Organic Synthesis (A2 Only)
6.9NMR Spectroscopy (A2 Only)
6.10Chromatography (A2 Only)
6.11A-A* (AO3/4) - Organic 2
Jump to other topics
1Physical Chemistry
1.1Atomic Structure
1.1.1Fundamental Particles
1.1.2Isotopes & Mass Number
1.1.3Mass Spectrometry
1.1.4Electron Shells, Sub-Shells & Orbitals
1.1.5Electron Configuration
1.1.6Ionisation Energy
1.1.7Factors Affecting Ionisation Energies
1.1.8Trends of Ionisation
1.1.9Specific Impacts on Ionisation Energies
1.1.10End of Topic Test - Atomic Structure
1.1.11A-A* (AO3/4) - Atomic Structure
1.2Amount of Substance
1.3Bonding
1.3.1Ionic Bonding
1.3.2Covalent & Dative Bonding
1.3.3Carbon Structures
1.3.4Metallic Bonding
1.3.5Physical Properties
1.3.6Shapes of Molecules
1.3.7Polarity
1.3.8Intermolecular Forces
1.3.9Intermolecular Forces 2
1.3.10End of Topic Test - Bonding
1.3.11Exam-Style Question - Shape of Molecules
1.3.12A-A* (AO3/4) - Bonding
1.4Energetics
1.5Kinetics
1.6Equilibria
2Physical Chemistry 2 (A2 Only)
2.1Thermodynamics (A2 Only)
2.2Rate Equations (A2 Only)
2.3The Equilibrium Constant Kp (A2 Only)
2.4Electrochemical Cells (A2 Only)
2.5Acids & Bases (A2 Only)
2.5.1Brønsted-Lowry Acids & Bases (A2 Only)
2.5.2pH (A2 Only)
2.5.3The Ionic Product of Water (A2 Only)
2.5.4Weak Acids & Bases (A2 Only)
2.5.5pH Curves & Titrations (A2 Only)
2.5.6pH Curves & Titrations 2 (A2 Only)
2.5.7Buffer Solutions (A2 Only)
2.5.8End of Topic Test - Acids & Bases
2.5.9Exam-Style Question - Weak Acids
2.5.10A-A* (AO3/4) - Acids & Bases
3Inorganic Chemistry
3.1Periodicity & Trends
4Inorganic Chemistry 2 (A2 Only)
4.1Period 3 (A2 Only)
4.2Transition Metals (A2 Only)
4.2.1General Properties (A2 Only)
4.2.2Substitution Reactions (A2 Only)
4.2.3Shapes of Complex Ions (A2 Only)
4.2.4Colours of Ions (A2 Only)
4.2.5Variable Oxidation States (A2 Only)
4.2.6Titrations (A2 Only)
4.2.7Homogeneous Catalysts (A2 Only)
4.2.8Heterogeneous Catalysts (A2 Only)
4.2.9End of Topic Test - Transition Metals
4.2.10A-A* (AO3/4) - Transition Metals
4.3Reactions of Ions in Aqueous Solutions (A2 Only)
5Organic Chemistry 1
5.1Introduction
5.2Alkanes
5.3Halogenoalkanes
5.4Alkenes
5.5Alcohols
5.6Organic Analysis
5.7A-A* (AO3/4) - Organic 1
6Organic Chemistry 2 (A2 Only)
6.1Optical Isomerism (A2 Only)
6.2Aldehydes & Ketones (A2 Only)
6.3Carboxylic Acids & Esters (A2 Only)
6.4Aromatic Chemistry (A2 Only)
6.5Amines (A2 Only)
6.6Polymers (A2 Only)
6.7Biological Organic (A2 Only)
6.8Organic Synthesis (A2 Only)
6.9NMR Spectroscopy (A2 Only)
6.10Chromatography (A2 Only)
6.11A-A* (AO3/4) - Organic 2
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