Crude Oil, Fuels and Organic Chemistry

What is crude oil?

A mixture of hydrocarbons

What is a hydrocarbon?

A compound made of hydrogen and carbon only

How is crude oil separated?

Fractional distillation: vaporised, then condensed at different points in column.

How does carbon chain length affect viscosity and colour?

The longer the chain the more viscous the compound is, also the darker in colour it becomes

How does carbon chain length affect boiling point?Why?

The longer the chain the higher the boiling point as there are stronger forces between molecules.

How does carbon chain length ignition?

The shorter the chain length, the easier it is to ignite

Describe combustion of fuels

Burning in oxygen to produce carbon dioxide and water.

Give 2 advantages of using hydrogen as a fuel

Water is the only product of combustion so doesn’t contribute to global warming. Made from water so is renewable

Give two disadvantages of using hydrogen as a fuel.

Lots of energy needed to produce it, storage requires bulky and heavy pressurized containers.

Which three things make up the fire triangle?

Fuel, Oxygen and heat

What is cracking?

heating hydrocarbons at high temperatures with a catalyst to make them break down into smaller molecules.

What is the general formula for an alkene?

𝐶𝑛𝐻2

Describe how you would prepare crystals of salt from an acid and an insoluble base

Add excess base to use up all the acid, filter to remove excess base, evaporate water to form crystals

Name the first five alkanes

methane, ethane, propane, butane, pentane

How would you test for alkenes?

Add bromine water, will change from orange brown to colourless

What is a monomer?

A small reactive molecule that can be joined together to make a polymer.

State the uses of polythene and poly(propene)?

polythene = bags, plastic bottles

poly(propene) = ropes and crates

State the uses of poly(vinylchloride) and poly(tetrafluoroethene)

PVC = drain pipes window frames

PTFE = non - stick pans

What are the environmental issues with using plastics?

take up space in landfill, don’t bio-degrade, made from crude oil (a non-renewable resource)

Give the equation for calculating the number of moles in a solutions

Moles = Volume (dm³) x Concentration (moldm^-3)

What is the difference between a strong and weak acid?

Stronger acids have a lower pH (pH1-2), weaker acids have a higher pH (3-4)

What is the difference between a dilute and a concentrated acid?

Concentrated acids don’t contain much water wheres dilute acids do.

How would you identify Fe2+, Fe3+ and Cu2+ ions with sodium hydroxide solution?

Fe2+- green precipitate

Fe3+- brown precipitate

Cu2+- blue precipitate.

Give the ionic equation for Fe2+ reaction with OH-

𝐹𝑒^2+(𝑎𝑞) + 𝑂𝐻-(𝑎𝑞) − + 𝐹𝑒(𝑂𝐻)2(𝑠)

What are the products of electrolysis of water?

Hydrogen and Oxygen

What happens during electrolysis if there are more than one positive and negative ion?

When there are competing ions it is the least reactive ion that will form at the electrode.

What are the products of electrolysis of slt water?

Chlorine gas, hydrogen gas and sodium hydroxide solution.

Give two other uses of electrolysis.

electroplating, purification of copper.

How is ethanol made from sugar?

fermentation of sugar using an enzyme found in yeast. Carbon dioxide is produced as a waste product.

How can you test for alcohols?

Use acidified potassium dichromate, a colour change from orange to green is seen

What issues arise from the use of ethanol in alcoholic drinks?

anti social behaviour, health issues such as liver damage

Give two others uses of ethanol

Solvent and fuel

What are the benefits of using bioethanol as a fuel?

Renewable and Carbon neutral

What happens during oxidation of ethanol?

Ethanoic acid is made, this is slow process and leads to beer and wine going 'off'

What is infrared spectroscopy used for?

Identify the presence of certain bonds in organic molecules