3A - Intro to organic

What does homologous series mean?

A series of compounds with the same General molecular formula and same functional group

What does saturated mean?

Single carbon carbon bonds only

What's a hydrocarbon?

Only contains hydrogen and carbon

What does aliphatic mean?

Compounds that do not contain a benzene ring

What does structural isomerism mean?

Molecules with the same molecular formula but a different structural formula

What happens to the number of isomers as the number of carbon atoms increase?

Increase

What are the three types of structural isomers?

Chain, position and functional group

What does chain isomerism mean?

The functional groups are the same but there are different arrangements of the carbon skeleton

What does position isomerism mean?

Same skeleton and same groups attached but the groups are attached to diff carbon atoms. Functional groups are in different positiojs

What does functional group isomerism mean?

The same atoms arranged into different functional groups

What are stereoisomers?

Compounds with the same structural formula but with a different arrangement of the atoms in space

What is E/Z isomerism?

A type of stereoisomerism that occurs in molecules that contain carbon-carbon double bonds

Why can only alkenes have E/Z isomers?

Lack of rotation around the carbon-carbon double bond

Where do Z isomers appear?

Groups on the (Z)same (z)side

Where do E isomers appear?

Groups on the opposite side

What are the Cahn-Ingold-Prelog (CIP) priority rules?

The atom with the highest atomic number has the highest priority

How does crude oil form?

It's made from the remains of plants and animals, mainly plankton, that died millions of years ago and were buried in mud. Over millions of years, due to high pressure and temperature, the remains turned to crude oil.

How does fractional distillation work?

The crude oil is vaporised at about 350 degrees Celsius and it rises up through the trays. The largest hydrocarbons don't vapourise at all, because their boiling points are too high. As the crude oil vapour goes up the fractional column, it gets cooler creating a temperature gradient. As the alkanes get bigger their boiling point increases so each fraction condenses at a different temperature. The hydrocarbons with the lowest boiling points don't condense, they're drawn off as gases at the top of the column.

What does cracking do?

Converts long chain alkanes into shorter alkanes and alkenes (more useful fractions)

What is the test for alkenes?

decolourisation of bromine water

What are the conditions for thermal cracking?

High temperature 1000 degrees and High pressure 70atm

What are the products of thermal cracking?

Lots of alkenes are produced

What are the uses of the alkenes formed by cracking?

Used to make polymers

What are the conditions for catalytic cracking?

zeolite catalyst, high temperature (500degrees), slight pressure

What are the products of catalytic cracking?

Aromatic hydrocarbons and motor fuels

Advantages of catalytic cracking?

Catalyst cuts costs and increases rate of reqactions

What is the origin of particulates?

Incomplete combustion

What are the effects of particulates?

Global dimming and health problems for humans

What is the problem with unburned hydrocarbons?

React with nitrogen oxides in sunlight to form ground-level ozone

What are the effects of unburnt hydrocarbons?

Smog

What pollutants can be minimised with catalytic converters?

Unburned hydrocarbons, carbon monoxide and nitrogen oxides

What's the origin of carbon monoxide?

Not enough O2 for fuel burning

What major polluting affect does CO lead to?

Carbon monoxide poisoning

What's the origin of carbon dioxide?

Burning of fossil fuels

What major polluting affect does carbon dioxide lead to?

Global warming

What are the origins of nitrogen oxides?

In car engines when N2 and O2 react in high temps

What major polluting effect does nitrogen oxides lead to?

Acid rain and global dimming

What's the origin of sulphur dioxide?

Combustion of coal as sulphur is oxidised

What are the major polluting effects of sulphur dioxide?

Acid rain (destroys vegetation, aquatic life and corrodes buildings)

How can sulfur dioxide be minimised?

Reacted with powdered limestone to form calcium sulfate

What is a free radical?

A species with a free unpaired electron

What is free radical substitution?

Alkanes react with halogens in the presence of UV light to produce a halogenoalkane and a halogen halide

What are the three steps of free radical substitution?

initiation, propagation, termination

What happens in the initiation stage?

The halogen bond is broken in the presence of UV light

What does homolytically mean?

Both atoms are the same

What does hetrolytically mean?

Both atoms are different

What kind of reaction is free radical substitution?

A chain reaction

What does ozone absorb?

A lot of UV radiation from the suns rays

How is ozone naturally produced?

Oxygen is broken down by homolytic fission to produce free radicals

What do chlorofluorocarbons do to the ozone?

Destroy it