ALKANES

Created by: samsh
Created on: 01-06-16 12:04

explain why as the carbon chain gets longer the boiling increases...

Alkanes are simple molecular structures. van der waals forces between molecules as chain length increases - bigger molecules means more electrons. van der waals forces increase in strength so more energy needed to separate.

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explain why for chain isomers, as the amount of branching increases the boiling point decreases...

alkanes are simple molecular structures. The moe branching means less contact surface area between molecules. the van der waals forces are weaker , so less energy is required to separate molecules.

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What conditions are needed for thermal cracking?

* 700 to 1200K *high pressure of 7000kPa *one of the products must be an alkane

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What conditions are needed for catalytic cracking?

* Zeolite catalyst *High temperature of 720K *pressure slightly above atomospheric

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equation for complete combustion

ALKANE + OXYGEN -> CARBON DIOXIDE + WATER

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Equation for incomplete combustion (1)

ALKANE +OXYGEN -> CARBON MONOXIDE + WATER

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Equation for incomplete combustion (2)

ALKANE + OXYGEN -> CARBON + WATER

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Explain the use of a catalyst converter

they contain a honeycomb of ceramic material which gives a large surface area. the metals such as platinum, rhodium catalyse reactions between pollutant gases to form less harmful ones.

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how are carbon monoxide and nitrogen monoxide removed?

2CO + 2NO -> N2 + 2CO2

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what is a free radical?

a species with a single unpaired electron.

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What is a substitution reaction?

a reaction in which an atom or a group of atoms is replaced with a different atom or group of atoms.

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what are the 3 stages in free radical suibstituion?

1- initiation 2-propagation 3- termination

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Other cards in this set

Card 2

Front

explain why for chain isomers, as the amount of branching increases the boiling point decreases...

Back

alkanes are simple molecular structures. The moe branching means less contact surface area between molecules. the van der waals forces are weaker , so less energy is required to separate molecules.