chemistry - organic chemistry

What is a homologous series?

A group of compounds that can all be represented by the same general formula

What is a hydrocarbon?

A compound that contains hydrogen and carbon atoms only

What is fuel?

A substance that releases energy when burned

What is combustion?

Burning in air (specifically oxygen)

What is a functional group?

An atom or group of atoms that determine the chemical properties of a compound.

What are structural isomers?

Molecules with the same molecular formula but different structural formulae.

What are polymers?

Large molecules that are made of repeated monomers joined by covalent bonds.

What is cracking?

The process in which long chain alkanes are converted into lake es and smaller chain alkanes.

What is cracking an example of?

Thermal decomposition

What are shorter chain alkanes used for?

To make Petronio, to meet demand

That are alkenes used for?

To make polymers (plastics)

What conditions are needed for cracking?

600-700°C and a Cary list of silicon dioxide and aluminium oxide

Why is carbon monoxide dangerous?

Colourless, odourless gas, poisonous

Binds to the haemoglobin, reducing the ability of the blood to carry oxygen around the body.

How is carbon monoxide formed?

Incomplete combustion.

What is carbon monoxide?

CO + H2O

As the carbon chain increases, hydrocarbons become

____ viscous

____ flammable

____ volatile

____ boiling points

____ in colour

• More viscous

• Less flammable

• Less volatile

• Higher boiling points

• Darker in colour

Explain how crude oil is fractionalised:

• Crude oil is heated up and vaporised. The vapours run un the column.

• The column has a temperature gradient. Hot at the bottom, cool at the top.

• As the vapours rise, they condense when they reach the temperature just below their boiling point.

• Longer hydrocarbons have higher boiling points so they condense near the bottom of the column.

Describe the temperature gradient of the fractional column!

Hot at the bottom, cool at the top.

What is a saturated hydrocarbon?

Hydrocarbons that only contain single bonds.

What is an unsaturated hydrocarbon?

Hydrocarbons that contain one or more double bonds.

When does incomplete combustion happen?

When there is not enough oxygen around for complete combustion.

Describe the disposal of addition polymers:

Addition polymers are non bio-degradable (cannot be broken down by bacteria in the environment).

This is because they have seeing bonds and are unreactive.

It is best to recycle them.

What are the two ways to dispose of addition polymers?

Landfill and incineration

What are the pros and cons of landfill?

Pros: no greenhouse gases produces, cheap

Cons: ugly, smelly, uses lots of land, waste can be there for many years.

Discuss the pros and cons of incineration:

Pros: require little space, can produce heat and electricity.

Cons: expensive to build and maintain plant, produces greenhouse gases, ash produces still has to go to landfill.

What is polymerisation?

The joining of lots of small molecules (monomers) to make one big molecule (polymers)

How do you test for unsaturated hydrocarbons and describe the colour change?

Add bromine water. Is there are unsaturated molecules, the bromine water will turn from orange to colourless.

What is an isomer?

Molecules with the same molecular formula but a different structural formula.

Describe the reaction of ethane + bromine:

Substitution reaction

Only works in uv light

Orange bromine solution slowly looses colour

Describe the reaction of ethene + bromine

Addition reaction

Works without uv light

Orange bromine solution quickly looses its colour.

What is the alkane formula?

What is the alkene formula?