GCSE Chemistry: Organic chemistry 1

What is an organic molecule?

a carbon-based molecule

What is a homologous series?

A family of organic compounds that have the same functional group, similar chemical properties and the same general formula

What is a functional group?

a group of atoms responsible for the characteristic reactions of a particular compound.

How was crude oil formed?

Remains of plankton deposited in mud on the seabed. These remains were covered by sediments that became layers of rock when compressed over millions of years - the crude oil and natural gas were trapped in the layers of rock

How are fuels extracted from crude oil?

Fractional distillation

Describe the fractional distillation of crude oil

1. Crude oil is heated to 350 C in a furnace and the vapours enter the fractionating column.

2. The column is hottest at the bottom and cooler at the top

3. These vapours are hydrocarbons of different lengths and boiling points. The small chain hydrocarbons condense at the top. These hydrocarbons are of low viscosity and high volatility

4. When the hydrocarbon reaches the boiling point the fraction condenses and is collected into trays

5. Heavy droplets of bitumen do not boil and are collected from the bottom and methane gas is collected at the top

What is a fraction?

A mixture of hydrocarbons with a narrow range of boiling points

What are products of complete combustion of a fuel?

Carbon dioxide (CO2) and Water (H20)

What are products of incomplete combustion?

Water, Soot (C) and/or Carbon monoxide (CO)

What do greenhouse gases cause?

Global warming and CO is toxic

What causes acid rain?

Sulfur dioxide (from oxidation of sulfur) and Nitrogen oxides (formed at high temperature reactions between oxygen and nitrogen in air)

What are alkanes?

saturated hydrocarbons

What is a saturated molecule?

A molecule that only contains single covalent bonds

What is the general formula for an alkane?

CnH2n+2

What are uses for alkanes?

fuels

What is cracking?

The breaking down of long-chain alkanes into alkenes and shorter-chain alkanes

What are the two types of cracking?

Catalytic and steam cracking

What are alkenes?

Hydrocarbons with a double carbon-carbon bond

What is the general formula for alkenes?

CnH2n

What is the functional group for alkenes?

carbon-carbon double bond

What reactions do alkenes have?

Addition reactions

What is the product of addition with halogens?

Haloalkanes

What is the product of addition with hydrogen? (nickel catalyst)

Alkanes

What is the product of addition with steam? (conc. H3PO4 catalyst)

Primary Alcohols

How can you distinguish between an alkane and an alkene?

Add both to a solution of bromine water. If it is an alkene the bromine water with go from orange to colourless.